Advances on Mechanics, Design Engineering and Manufacturing

This paper seeks to establish the foundations of a methodology offering practical guidance to aid the innovative design of Engineered Object functionality. The methodology is set in a P-To-V framework. The concept of the framework is borrowed from an earlier work, but constituent elements are new. Much recent work focuses on different aspects of innovation. However, there seems to be a gap for an overarching framework guiding the process of innovative design but with a clear focus on the technical aspects of the object to be engineered. In other words, ‘A Systematic Methodology For Engineered Object Design’. The term ‘Engineered Object’ rather than ‘Product’ has been used, to make the scope as wide as possible. Three Innovation Groups are proposed – Elemental, Application and Combination. From a case study review, factors are identified which provided a ‘spark of imagination’ leading to technical problem resolution. The term Influencing Factor is defined along with the concept of Innovation Groups. The Influencing Factor Matrix is generated to highlight patterns linking Innovation Group and Influencing Factor(s). The final step in the construction of the P-To-V Model is the generation of an overarching Model Operating Chart, which aggregates the various elements of the model.

Topological optimization can be considered as one of the most general types of structural optimization. Between all known topological optimization techniques, the Evolutionary Structural Optimization represents one of the most efficient and easy to implement approaches. Evolutionary topological optimization is based on a heuristic general principle which states that, by gradually removing portions of inefficient material from an assigned domain, the resulting structure will evolve towards an optimal configuration. Usually, the initial continuum domain is divided into finite elements that may or may not be removed according to the chosen efficiency criteria and other parameters like the speed of the evolutionary process, the constraints on displacements and/or stresses, the desired volume reduction, etc. All these variables may influence significantly the final topology. The main goal of this work is to study the influence of both the different optimization parameters and the used efficiency criteria on the optimized topology. In particular, two different evolutionary approaches, based on the von Mises stress and the Strain Energy criteria, have been implemented and analyzed. Both approaches have been deeply investigated by means of a systematic simulation campaign aimed to better understand how the final topology can be influenced by different optimization parameters (e.g. rejection ratio, evolutionary rate, convergence criterion, etc..). A simple case study (a clamped beam) has been developed and simulated and the related results have been compared. Despite the object simplicity, it can be observed that the evolved topology is strictly related to the selected parameters and criteria.

The racing solar cars are characterized by the constant pursuit of energy efficiency. The tight balance between energy inputs and consumption is the main reason to seek optimization in different areas. The vehicle weight is directly related to the energy consumption via rolling resistance of the tires. The relation between weight and energy consumption is quantified. The structural optimization techniques are studied and a series of rules is obtained to iteratively improve the shape of structural parts reducing its weight. The implementation is done in a practical case and satisfactory results are achieved.

The paper discusses the problem of the correct identification of the Objective Function and the associated SNR function that designers must choose when employing the Taguchi method in product design, considering this step as the basic element to quantify the uncertainty of the device performance prediction. During product design, when many design aspects must still be understood by the design team, it is important to identify the most suitable “loss function” that can be associated with the characteristic function. The second step considers the variability of the characteristic function. The Taguchi method considers many Signal to Noise Ratio functions whereas in the paper the use of a unique function is suggested for all kinds of loss function. The discussion is argued in the context of so-called parameter design, with the perspective of identifying the best ranges of variation of the parameters that designers have identified as influential on the characteristic function, and also to adjust those ranges in order to obtain twofold results: reduce Bias between the mean value of the characteristic function response and the target value; obtain less variability of the characteristic function. The discussion of a case of study will point out the approach and the use of a unique Noise Reduction function.

The complexity of flow inside cylinder leads to develop new accurate and specific models. Influencing the 2-stroke engine efficiency, the scavenging process is particularly dependent to the cylinder design. To improve the engine performances, the enhancement of the chamber geometry is necessary. The development of a new neuro-separated meta-model is required to represent the scavenging process depending on the cylinder configuration. Two general approaches were used to establish the meta-model: neural networks and NTF (Non-negative Tensor Factorization) separation of variables. To fully describe the scavenging process, the meta-model is composed by four static neural models (representing the Heywood parameters), two dynamic neural models (representing the evolution of gases composition through the ports) and one separated model (the mapping of the flow path during the process). With low reduction errors, these two methods ensure the accuracy and the relevance of the meta-model results. The establishment of this new meta-model is presented step by step in this article.

Seen the significant number of parts constituting a mechanism, assembly or disassembly sequence planning became a very hard problem. The subassembly identification concept can constitutes the most original way to solve this problem particularly for complex product. This concept aims to break down the multipart assembly product into particular number of subassemblies, and each subassembly is constituted by a small number of parts. Consequently the generation of assembly or disassembly sequence planning between parts can be determined relatively easily because it becomes between the subassemblies constituting the product. Then, each subassembly is assembled or disassembled using the same approach. In literature subassemblies identification approach from CAD model is not very developed and still a relevant research subject to be improved. In this paper, a novel subassemblies identification approach is presented. This proposed approach starts with the exploration of the CAD assembly data to get an adjacency matrix. Then, the extracted matrix is enriched by adding the contact in all directions in order to determine and to classify the base parts initiator of each subassembly. The next step is to identify subassemblies using a new matrix called sum matrix obtained from contact all direction matrix and fit matrix. For better discussing and explaining the stages of the proposed approach an example of CAD assembly product is presented in all sections of this paper.

Conceptual design is a central phase for the generation of the best product configurations. The design freedom suggests optimal solutions in terms of assembly, manufacturing, cost and material selection but a guided decision making approach based on multi-objective criteria is missing. The goal of this approach is to define a framework and a detailed approach for the definition of feasible design options and for the selection of the best one considering the combination of several production constrains and attributes. The approach is grounded on the concept of functional basis and the module heuristics used for the definition of product modules and the theory of Multi Criteria Decision Making approach (MCDM) for a mathematical assessment of the best design option. A complex product (tool-holder carousel of a machine tool) is used as a case study to validate the approach. Product modules have been re-designed and prototyped to efficiently assess the gain in terms of assembly time, manufacturability and costs.

The present paper is focused on the theoretical and experimental analysis of a three-axes MEMS gyroscope, developed by ST Microelectronics, implementing an innovative feedforward PI quadrature compensation architecture. The gyroscopes structure is explained and equations of motion are written; modal shapes and frequencies are obtained by finite element simulations. Electrostatic quadrature compensation strategy is explained focusing on the design of quadrature cancellation electrodes. A new quadrature compensation strategy based on feedforward PI architecture is introduced in this device to take into account variations of device parameters during lifetime. Obtained results show a significant reduction of the quadrature error resulting in a improved performance of the device. Fabrication and test results conclude the work.

In recent years, more and more research has been conducted in close collaboration with manufacturers to design robust and profitable dismantling systems. Thus, engineers and designers of new products have to consider constraints and disassembly specifications during the design phase of products not only in the context of the end of life but more precisely in the product life cycle. Consequently, optimization of disassembly process of complex products is essential in the case of preventive maintenance. In Fact, Disassembly Sequence Plan (DSP), which is among the combinatorial problems with hard constraints in practical engineering, becomes an NP-hard problem. In this research work, an automated DSP process based on a metaheuristic method named “Ant Colony Optimization” is developed. Beginning with a Computer Aided Design (CAD) model, a collision analysis is performed to identify all possible interferences during the components’ motion and then an interference matrix is generated to identify dynamically the disassembly parts and to ensure the feasibility of disassembly operations. The novelty of the developed approach is presented in the introduction of new criteria such as the maintainability of the usury component with several other criteria as volume, tools change and disassembly directions change. Finally, to highlight the performance of the developed approach, an implemented tool is developed and an industrial case is studied. The obtained results prove the satisfactory side of these criteria to identify a feasible DSP in a record time.

In the production of utility poles, used for transmission, telephony, telecommunications or lighting support, for many years, the steel has almost entirely replaced wood. In recent years, however, new composite materials are a great alternative to steel. The questions are: is the production of composite better in terms of environmental impact? Is the lifecycle of composite pole more eco-sustainable than lifecycle of steel pole? Where is the peak of pollution inside the lifecycle of both of technologies? In the last years, in order to deal with new European polices in environmental field, a new approach for the impact assessment has been developed: the Life Cycle Assessment. It involves a cradle-to-grave consideration of all stages of a product system. Stages include the extraction of raw material, the provision of energy for transportation and process, material processing and fabrication, product manufacture and distribution, use, recycling and disposal of the wastes and the product itself. A great potentiality of the Life Cycle assessment approach is to compare two different technologies designed for the same purpose, with the same functional unit, for understanding which of these two is better in terms of environmental impact. In this study, the goal is to evaluate the difference in environmental terms between two different technologies used for the production of poles for illumination support.

In this paper, we propose a methodology to define a predictive model of complex systems’ quality. This methodology is based on a definition of system’s quality through factors and allows taking into account the specificities of the company. The model obtained with this methodology helps quality practitioners to have an objective view of system’s quality and predict the future quality of the system all along its lifecycle. This approach is illustrated through its application to design a model for compliance prediction, in an aeronautic and defense group, MBDA.

The concept of mobile manufacturing systems is presented in the literature as an enabler for improving company competitiveness by cost reduction, delay respect and quality control. In comparison with classical sedentary systems, added characteristics should be taken into consideration, such as the system life phases, the dependency to the production location, human qualification as well as means supply constraints. Such considerations might be addressed as soon as possible in the design process. This paper aims at presenting a contribution for the design of mobile manufacturing systems based on three analysis: (1) an analysis of the mobile manufacturing system features (2) an identification of the attributes enabling the system mobility assessment, and (3) the proposal of a framework for mobile production system design considering new context-specific decision criteria.

In this paper a new methodology of automated demoldability analysis for parts manufactured via plastic injection molding is presented. The proposed algorithm uses as geometric input the faceted surface mesh of the plastic part and the parting direction. Demoldability analysis is based on a sequential model to catalog nodes and facets of the given mesh. First, the demoldability of nodes is analyzed, subsequently, from results of previous nodes analysis, facets of the mesh are cataloged in: demoldable (facets belong cavity and core plate), semi-demoldable (plastic part manufactured by mobile mechanisms, side cores) and non-demoldable (plastic part not manufacturable). This methodology uses a discrete model of plastic part, which provides an additional advantage since the algorithm works independent of the modelling software and creates a new virtual geometry providing information on its manufacture, exactly like CAE software. All elements of the mesh (nodes and facets) are stored in arrays, according with their demoldability category, with information about their manufacture for possible uses in other CAD/CAE applications related to design, machining and costs analysis of injection molds.

Sustainable product development initiatives have been evolving for some time to support companies improve the efficiency of current production and the design of new products and services through supply chain management. This work aims at integrating environmental criteria in product development projects at the same time that traditional product criteria are fulfilled. The manufacturing process of an airbrush was studied. Different strategies focused on the optimization of raw materials and energy consumption along the manufacturing operations, the identification of the product components that could be modified according to a DFA analysis, the evaluation of the recyclability rate for the materials making up the product and the identification of those materials with the highest environmental impact, were applied. An approach based on two main strategies, optimization of materials and optimization of processes is proposed to be used by engineering designers for a progressive education to eco-design practice.

The main idea of this paper is to present a collaborative framework for PSS development process. Focused on the engineering phase, this research will use the modular ontology to support the management of the interfaces between various engineering knowledge involved in the PSS development process. The supporting platform is developed as a part of a collaborative framework that aims to manage the whole PSS lifecycle.

Over the last decades many efforts are being made into either both, creating better products or improving processes, yet, generating more information, and usually leaving behind how to manage whole information that already exist and using it to improve the decision making process. This article is centred into the development of an information model that allows to have a multilevel traceability in early design stages, by definition of tracelinks of information at the design stages, where information evolves between from linguistic requirements into design variables. Regarding of the information the should be analysed the research is focused into the setting up of a graphic environment that will allow to determine relationships between different variables that exist in conceptual design, granting designers teams the opportunity to use that information in decision making situations in terms of knowing how changing one variable upsets any requirement. Finally, this article presents a case study of a design of a portable cooler in order to clarify the usage and opportunities present by the usage of the traceability model.

The paper describes a user-centered design (UCD) approach that has been adopted in order to develop and build a virtual museum (VM) system for the “Museum of the Bruttians and the Sea” of Cetraro (Italy). The main goal of the system was to enrich the museum with a virtual exhibition able to make the visitors enjoy an immersive and attractive experience, allowing them to observe 3D archaeological finds, in their original context. The paper deals with several technical and technological issues commonly related to the design of virtual museum exhibits. The proposed solutions, based on an UCD approach, can be efficiently adopted as guidelines for the development of similar VM systems, especially when very low budget and little free space are unavoidable design requirements.

The shipment of heritage artefacts for restoration or temporary/travelling exhibition has been virtually lacking in customised packaging. Hitherto, packaging has been empirical and intuitive which has unnecessarily put the artefacts at risk. So, this research arises from the need to identify a way of designing and creating packaging for artefacts which takes into account structural criticalities to deal with deteriorating weather, special morphology, constituent materials and manufacturing techniques. The proposed methodology for semi-automatically designing packaging for heritage artefacts includes the integrated and interactive use of Reverse Engineering (RE), Finite Element Analysis (FEA) and Rapid Prototyping (RP). The methodology presented has been applied to create a customised packaging for a small C3rd BC bronze statue of Heracles (Museo Civico “F.L. Belgiorno” di Modica -Italy). This methodology has highlighted how the risk of damage to heritage artefacts can be reduced during shipping. Furthermore, this approach can identify each safety factor and the corresponding risk parameter to stipulate in the insurance policy.

The emergence of additive manufacturing (AM) techniques in the last 30 years allows to build complex part by adding material in a layer-based fashion or spraying the material directly into the part or a substrate. Taking into account performance of these techniques in a ‘new remanufacturing strategy’ can open new ways to transform an end-of-life (EoL) part into a new part intended for another product. The strategy might allow a considerable material proportion of existing parts to be reused directly for producing new parts without passing through the recycling stage. In this work, the strategy enable the transformation of existing parts into desired parts is first presented. The strategy uses an adequate sequence of additive and subtractive operations, as well as inspection operations to achieve the geometry and quality of final parts. This sequence will be designed from a set of AM features and machining features, which are extracted from available technical information and the CAD models of existing part, and final part. The core of the paper focuses on the feature extraction approach. The approach development is based on the knowledge of AM processes and machining process, as well as the specifications of final part.

Additive Manufacturing (AM), also known as 3D printing, has been introduced since mid 90’ but it begins to have a broader use along last ten years. The first uses of AM process were for rapid prototyping or for 3D sample illustration due to the weak performances of mechanical characteristics of the materials available. However, even if this technology can provide answers for mechanical requirements, it will be largely used only if geometrical and dimensional characteristics of generated parts are also at the required level. In this context, it is necessary to investigate and identify any common dimensional and/or geometrical specifications of the parts generated by AM process. Highlighting singularity of AM systems should be based on the fabrication and measurement of standardized artefacts. Even if those test parts allow assessing some important characteristics of AM systems, there are still some challenges to characterize the capacity of generating freeform surfaces and features. In the literature, none of existing test parts are proposing those kind of features even if the generation of free-form surfaces is a significant benefit of AM systems. In this context, the aim of this paper is to provide a metrological comparative study on the capacity of an AM system to generate freeform parts based on an artefact.

The purpose of this paper is to assess the main effects on the geometric errors in terms of flatness, circularity and cylindricity based on the size of the printed benchmarks and according to the position of the working plane of the 3D printer. Three benchmark models of different sizes, with a parallelepiped and cylinder shape placed in five different positions on the working plane are considered. The sizes of models are chosen from the Renard series R40. Benchmark models are fabricated in ABS (Acrylonitrile Butadiene Styrene) using Zortrax M200 3D printer. A sample of five parts for each geometric category, as defined from the R40 geometric series of numbers, is printed close to each corner of the plate, and in the plate center position. Absolute Digimatic Height Gauge 0-450mm with an accuracy of ±0.03mm by Mitutoyo is used to perform all measurements: flatness on box faces, and circularity/cylindricity on cylinders. Results show that the best performances, in terms of form accuracy, are reached in the area center printable while they decrease with the sample size. Being quality a critical factor for a successful industrial application of the AM processes, the results discussed in this paper can provide the AM community with additional scientific data useful to understand how to improve the quality of parts which may be obtained through new generations of 3D printer.

Additive manufacturing technologies enable the fabrication of parts characterized by shape complexity and therefore allow the design of optimized components based on minimal material usage and weight. In the literature two approaches are available to reach this goal: adoption of lattice structures and topology optimization. In a recent work a Computer-Aided method for generative design and optimization of regular lattice structures was proposed. The method was investigated in few configurations of a cantilever beam, considering six different cell types and two load conditions. In order to strengthen the method, in this paper a number of test cases have been carried out. Results explain the behavior of the method during the iterations, and the effects of the load and of the cell dimension. Moreover, a visual comparison between the proposed method and the results achieved by topology optimization is shown.

The work presented in this paper has focused on process planning and operations management of Additive Manufacturing (AM) through the hereafter mentioned standards such as ISO 10303 and ISO 14649, ISO 15531, ISO/CD 18828 and Unified Manufacturing Resource Model (UMRM). We have combined these standards to integrate process implementations, manufacturing management and control and information flows. The objective of this work is to standardize manufacturing process for AM. Similarly, the UMRM is introduced to develop a unified manufacturing resource service platform, which can provide the required information regarding machine tools to automate the decision making in process planning and operations management.

Topological optimization is often used in the design of light-weight structures. Additive manufacturing allows to manufacture complex shapes and exploits the full potential of this tool. However, topology optimization results is a discrete representation of the optimal topology, requiring the designers to ‘manually’ create a CAD model. This process can be very time consuming, and hardly penalizes the design process efficiency. In this paper, several possible approaches to get a CAD model from the topological optimization results are proposed. From case studies, benefits and drawbacks of these approaches are discussed in order to help engineers in the choice of their approach.

Additive Manufacturing (AM) is becoming a promising technology capable of building complex customized parts with internal geometries and graded material by stacking up thin individual layers. However, a comprehensive geometric model for Additive Manufacturing is not mature yet. Dimensional and form accuracy and surface finish are still a bottleneck for AM regarding quality control. In this paper, an up-to-date review is drawn on methods and approaches that have been developed to model and predict shape deviations in AM and to improve geometric quality of AM processes. A number of concluding remarks are made and the Skin Model Shapes Paradigm is introduced to be a promising framework for integration of shape deviations in product development, and the digital thread in AM.

The growing potential of additive manufacturing technologies is currently being boosted by their introduction in directly manufacturing of ready-to-use products or components, regardless of their shape complexity. Taking advantage from this capability, a full set of new solutions to be explored is related to the possibility to directly manufacture joints or mechanisms as a unibody structure. In this paper, the preliminary design of a robotic mechanism is presented. The component is designed in order to be manufactured as a unibody structure by means of an Additive Manufacturing technology. Fused Deposition Modelling technique is used to print the mechanic arm as a single component, composed by different functional parts already assembled in the CAD model. Soluble support material is commonly used to support undercuts: in this case it is also deposited in the space between two adjacent parts of the same component, in order to allow the relative motion and the kinematic connection between them. The design process considers component optimization in relation to both the specific manufacturing technique and both the interaction between the different parts of the same component, in order to guarantee the proper relative motions. The conceived mechanism consists in a robotic structure in which the mechanical arm is bounded to a base and connected to a plier on the opposite side. The effect of clearance between all the kinematic parts is evaluated in order to assess mechanism degree of mobility in relation to the manufacturing process and components tolerances and geometry.

Additive manufacturing is a rapidly expanding technology. It allows the creation of very complex 3D objects by adding layers of material, in spite of the traditional production systems based on the removal of material. The development of additive technology has produced initially a generation of additive manufacturing techniques restricted to industrial applications, but their extraordinary degree of innovation has allowed the spreading of household systems. Nowadays, the most common domestic systems produce 3D parts through a fused deposition modeling process. Such systems have low productivity and make, usually, objects with no high accuracy and with unreliable mechanical properties. These side effects can depend on the process parameters. Aim of this work is to study the influence of some typical parameters of the additive manufacturing process on the prototypes characteristics. In particular, it has been studied the influence of the layer thickness on the shape and dimensional accuracy. Cylindrical specimens have been created with a 3D printer, the Da Vinci 1.0A by XYZprinting, using ABS filaments. Dimensional and shape inspection of the printed components has been performed following a typical reverse engineering approach. In particular, the point clouds of the surfaces of the different specimens have been acquired through a 3D laser scanner. After, the acquired point clouds have been post-processed, converted into 3D models and analysed to detect any shape or dimensional difference from the initial CAD models. The obtained results may constitute a useful guideline to choose the best set of the process parameters to obtain printed components of good quality in a reasonable time and minimizing the waste of material.

In additive manufacturing, the part geometry, including its internal structure, can be optimized to answer functional requirements by optimizing process parameters. This can be performed by linking process parameters to the resulting manufactured geometry. This paper deals with an original method for surface geometry characterization of printed parts (using Fused Filament Fabrication FFF) based on 3D Computer Tomography (CT) measurements. From 3D measured data, surface extraction is performed, giving a set of skin voxels corresponding to the internal and external part surface. A multi-scale analysis method is proposed to analyse the relative internal area of the total surface obtained at different scales (from sub-voxel to super-voxel scales) with different process parameters. This analysis turns out to be relevant for filling strategy discrimination.

Additive manufacturing (AM) has enabled the building of parts with new shapes and geometrical features. As this technology modifies the practices, new knowledge is required for designing and manufacturing properly. To help experts create and share this knowledge through formalization, our paper focusses on testing three knowledge elicitation techniques. After defining knowledge concepts we present the State of Art in knowledge elicitation and a methodology. A case study about support creation for AM points out: the assets and limits of the techniques; the different types of knowledge elements per technique; some contradictions between experts. We finally propose collective tools for a better elicitation and formalization of AM knowledge.

Nowadays, the most updated CAE systems include structural optimization toolbox. This demonstrates that topological optimization is a mature technique, although it is not a well-established design practice. It can be applied to increase performance in lightweight design, but also to explore new topological arrangements. It is done through a proper definition of the problem domain, which means defining functional surfaces (interface surfaces with specific contact conditions), preliminary external lengths and geometrical conditions related to possible manufacturing constraints. In this sense, its applicability is possible for all kind of manufacturing, although, in Additive Manufacturing, its extreme solutions can be obtained. In this paper, we aim to present the general applicability of topological optimization in the design workflow together with a case study, exploited according to two design intents: the lightweight criterion and the conceptual definition of an enhanced topology. It demonstrates that this method may help to decrease the design efforts, which, especially in the case of additive manufacturing, can be reallocated for other kind of product optimization.

Integrating measurement operations for on-machine inspection in a 5-axis machine tool is a complex activity requiring a significant limitation of measurement time in order not to penalize the production time. When using a laser-plane sensor, time optimization must be done while keeping the quality of the acquired data. In this paper, a simulation tool is proposed to assess a given digitizing trajectory. This tool is based on the analysis of sensor configurations relatively to the geometry of the studied part.

Vibration-assisted drilling is a critical process applied on high-value products such as aeronautic parts. This process performs discontinuous cutting and improves the drilling behavior of some materials, including chip evacuation, heat generation, mean cutting force. Several research papers illustrated the differences between vibration-assisted and conventional drilling, hence demonstrating that conventional drilling models may not apply. In this process, the cutting conditions evolve drastically along the trajectory and the tool radius. The tool/material interferences (back-cutting and indentation) proved to significantly contribute to the thrust force. A method properly describing all rigid interferences is detailed. A local analysis of the influence of the tool geometry and process parameters over interferences is presented. Interferences distribution on the tool surfaces are highlighted, and the presence of back-cutting far away from the cutting edge is confirmed. A comparison is performed in conventional drilling between the predicted shape of the interferences on the tool surfaces and the real shape of a used tool. The most interfering areas of the tool surfaces are slightly altered to simulate a tool grind, the interference results are compared with the original tool geometry, and significant interference reduction is observed.

Composite materials nowadays are used in a wide range of applications in aerospace, marine, automotive, surface transport and sports equipment markets. For example, all aircraft’s composite parts have the potential to incur damage and therefore require repairs. These shocks can impact the mechanical behavior of the structure in a different ways: adversely, irretrievable and, in some cases, in a scalable damage. It is therefore essential to intervene quickly on these parts to make the appropriate repairs without immobilizing the aircraft for too long.The scarfing repair operation involves machining or grinding away successive ply layers from the skin to create a tapered or stepped dish scarf profile around the damaged area. After the scarf profile is machined, the composite part is restored by applying multiple ply layers with the correct thickness and orientation to replace the damaged area. Once all the ply layers are replaced, the surface is heated under a vacuum to bond the new material. The final skin is ground smoothed to retrieve the original design of the part. Currently, the scarfing operations are performed manually. These operations involve high costs due to the precision, heath precautions and a lack of repeatability. In these circumstances, the use of automated solutions for the composite repair process could bring accuracy, repeatability and reduce the repair’s time. The objective of this study is to provide a methodology for an automated repair process of composite parts, representative of primary aircraft structures.

Hybrid Manufacturing (HM) is oriented to combine the advantages of additive manufacturing, such as few limits in shape reproduction, good customization of parts, distributive production, minimization of production costs and minimization of waste materials, with the advantages of subtractive manufacturing, in terms of finishing properties and accuracy of dimensional tolerances. In this context, our research group presents a design technique that aims to data processing that switches between additive and subtractive procedures, to the costs and time of product-manufacturing optimization. The component prototyping may be performed combining different stages (addiction, gross milling, fine milling, deposition…) with different parameters and head/nozzles and is able to work with different materials either in addictive, either in milling. The present paper is dedicated to introduce different strategies, or in other terms, different combinations of machining features (addictive or deductive) and different materials to complete a prototype model or mold. The optimization/analysis piece of software is fully integrated in classic CAD/CAM environment for better supporting the design and engineering processes.

The automotive steering system inevitably presents internal friction that affects its response. This is why internal friction phenomena are carefully monitored either by OEMs and by vehicle manufacturers. An algorithm to predict the mechanical efficiency and the internal friction of a steering gear system has been developed by the ZF-TRW Technical Centre of Gardone Val Trompia and the University of Brescia, Italy. It is focused on mechanical steering gear of the rack and pinion type. The main contributions to the overall friction have been identified and modelled. The work is based on theoretical calculation as well as on experimental measurements carried out on a purpose-built test rig. The model takes into account the materials used and the gear mesh characteristics and enables the prediction of the steering gear friction performance before the very first prototypes are built.

This paper describes a part of the contribution of the CoMAS project (“In situ conservation planning of Underwater Archaeological Artifacts”), funded by the Italian Ministry of Education, Universities and Research (MIUR), and run by a partnership of private companies and public research centers. The CoMAS project aims at the development of new materials, techniques and tools for the documentation, conservation and restoration of underwater archaeological sites in their natural environment. This paper details the results achieved during the project in the development of an innovative electric tool, which can efficiently support the restorers’ work in their activities aimed to preserve the underwater cultural heritage in its original location on the seafloor. In particular, the paper describes the different steps to develop an underwater electric cleaning brush, which is able to perform a first rough cleaning of the submerged archaeological structures by removing the loose deposits and the various marine organisms that reside on their surface. The peculiarity of this work consists in a user centred design approach that tries to overcome the lack of detailed users’ requirements and the lack of norms and guidelines for the ergonomic assessment of such kind of underwater tools. The proposed approach makes a wide use of additive manufacturing techniques for the realization and modification of prototypes to be employed for in-situ experimentation conducted with the final users. The user tests have been addressed to collect data for supporting the iterative development of the prototype.

Complexity in cities is expected to become even higher in the short term, which implies the need to face new challenges. The Smart City (SC) model and its associate initiatives have become very popular for undertaking them but it is not often very clear what it really means. Starting with a previous classification of the initiatives developed under the SC model into two big categories, according to their approach to citizens, this paper aims to make a critical analysis of this model of city, and to propose the development of new initiatives for it based on Citizen-Centered Design methodologies. Living Labs, both as methodology and as organization, appear in this context as an interesting choice for developing initiatives with real citizen involvement along the entire design process, which it is expected to arise in later stages of research.

This research aims at moving from design for disabled people to design led by disabled people. This is achieved by defining a roadmap suggesting how to involve people affected by Autism Spectrum Disorder (ASD) in design. These people could represent an added value given their uncommon reasoning mechanisms. The core of the roadmap consists of tests involving groups of ASD and neurotypical people. These tests are performed using shapes; the testers are asked for interacting with these shapes and highlighting aroused functions, meanings and emotions. The outcomes are analyzed in terms of variety, quality, frequency and originality, and elaborated in order to pursue unforeseen, innovative design solutions.

Cardiovascular diagnosis, surgical planning and intervention are among the most interested in recent developments in the field of 3D acquisition, modelling and rapid prototyping techniques. In case of complex heart disease, to provide an accurate planning of the intervention and to support surgical planning and intervention, an increasing number of Hospitals make use of physical 3D models of the cardiac structure, including heart, obtained using additive manufacturing starting from the 3D model retrieved with medical imagery. The present work aims in providing an overview on most recent approaches and methodologies for creating physical prototypes of patient-specific heart and cardiac structures, with particular reference to most critical phases such as segmentation and aspects concerning converting digital models into physical replicas through rapid prototyping techniques. First, recent techniques for image enhancement to highlight anatomical structures of interest are presented together with the current state of the art of semi-automatic image segmentation. Then, most suitable techniques for prototyping the retrieved 3D model are investigated so as to draft some hints for creating prototypes useful for planning the medical intervention.

In traditional dentistry, orthodontics and maxillo-facial surgery, articulators are mainly used to simulate the dental occlusion. Dental implants and syndromes such as functional occlusion require instrumentation for the planning previous to the surgery. There are various mechanical articulators on the market. However, most of them only simulate the rotation of the jaw about an axis running through the virtual condyles. However, the real movement includes translation and rotation and differs from one patient to another. Surgeons and dentists require a comprehensive simulation system as a support for their work. This article describes the work carried out to develop a method to capture mandibular movement. Taking into consideration the market proposals and in comparison with them, this system is intended to be as cheap and simple as possible.

Orthodontic treatments based on removable thermoplastic aligners are becoming quite common in clinical practice. However, there is no technical literature explaining how the loads are transferred from the thermoformed aligner to the patient dentition. Moreover, the role of auxiliary elements used in combination with the aligner, such as attachments and divots, still needs to be thoroughly explained. This paper is focused on the development of a Finite Element (FE) model to be used in the design process of shape attributes of orthodontic aligners. Geometrical models of a maxillary dental arch, including crown and root shapes, were created by combining optical scanning and Cone Beam Computed Tomography (CBCT). Finite Element Analysis (FEA) was used to compare five different aligner’s configurations for the same tooth orthodontic tipping movement (rotation around the tooth’s center of resistance). The different scenarios were analyzed by comparing the moment along the mesio-distal direction of the tooth and the resulting moment-to-force ratio (M:F) delivered to the tooth on the plane of interest. Results evidenced the influence of the aligner’s configuration on the effectiveness of the planned orthodontic movement.

In the present work, the effect of Eruption Guidance Appliances (EGAs) on TemporoMandibular Joint (TMJ) disks stress level is studied. EGAs are orthodontic appliances used for early orthodontic treatments in order to prevent malocclusion problems. Commercially available EGAs are usually produced by using standard sizes. For this reason, they are not able to meet all the specific needs of each patient. In particular, EGAs are symmetric devices, while patient arches generally present asymmetric conditions. Thus, uneven stress levels may occur in TMJ disks, causing comfort reduction and potential damage to the most solicited disk. On the other hand, a customized EGA could overcome these issues, improving the treatment effectiveness. In this preliminary study, a Finite Element (FE) model was developed to investigate the effects of a symmetric EGA when applied to an asymmetric mouth. Different misalignment conditions were studied to compare the TMJ disks stress levels and to analyze the limitations of a symmetric EGA. The developed FE model can be used to design patient-specific EGAs, which could be manufactured by exploiting non-conventional techniques such as 3D printing.

The aim of regenerative medicine is replacing missing or damaged bone tissues with synthetic grafts based on porous interconnected scaffolds, which allow adhesion, growth, and proliferation of the human cells. The optimal design of such scaffolds, in the Bone Tissue Engineering field, should meet several geometrical requirements. First, they have to be customized to replicate the skeletal anatomy of the patient, and then they have to provide the proper trabecular structure to be successfully populated by the cells. Therefore, for modelling such scaffolds, specific design methods are needed to conceive extremely complex structures by controlling both macro and micro shapes. For this purpose, in the last years, the Computer Aided Design of Triply Periodic Minimal Surfaces has received considerable attention, since their presence in natural shapes and structures. In this work, we propose a method that exploit Triply Periodic Minimal Surfaces as unit cell for the development of customized trabecular scaffolds. The aim is to identify the mathematical parameters of these surfaces in order to obtain the target requirements of the bone grafts. For that reason, the method is implemented through a Generative Design tool that allow to interactively controlling both the porosity and the pores size of the scaffolds.

Clear thermoplastic aligners are nowadays widely used in orthodontics for the correction of malocclusion or teeth misalignment defects. The treatment is virtually designed with a planning software that allows for a definition of a sequence of little movement steps from the initial tooth position to the final desired one. Every single step is transformed into a physical device, the aligner, by the use of a 3D printed model on which a thin foil of plastic material is thermoformed. Manufactured aligners could have inherent limitations such as dimensional instability, low strength, and poor wear resistance. These issues could be associated with material characteristics and/or with the manufacturing processes. The present work aims at the characterization of the manufactured orthodontic devices. Firstly, mechanical properties of different materials have been assessed through a set of tensile tests under different experimental conditions. The tests have the purpose of analyzing the effect that the forming process and the normal use of the aligner may have on mechanical properties of the material. The manufacturing process could also introduce unexpected limitations in the resulting aligners. This would be a critical element to control in order to establish resulting forces on teeth. Several studies show that resulting forces could be greatly influenced by the aligner thickness. A method to easily measure the actual thickness of the manufactured aligner is proposed. The analysis of a number of real cases shows as the thickness is far to be uniform and could vary strongly along the surface of the tooth.

The purpose of this paper is to study two types of knee prosthesis that are based on the Finite Element Method (FEM). The process to generate the Finite Element (FE) models was conducted in several steps. A 3D geometric model of a healthy knee joint was created using 3D scanned data from an anatomical knee model. This healthy model comprises a portion of the long bones (femur, tibia and fibula) as well as by the lateral and medial meniscus, cartilage and ligaments. The digital model that was obtained was repaired and converted to an engineering drawing format using CATIA© software. Based on the foregoing format, two types of artificial knee prostheses were designed and assembled. Mentat Marc© software was used to model the healthy and artificial knee FE models. The healthy and artificial knee FE models were subjected to different loads. The an-thropometry of the human body that was studied and the combination of loads to apply to the knee were obtained by use of 3D Static Strength Prediction software (3DSSPP©). The Von Mises stresses, as well as all the relative displacements of the components of the healthy and artificial knee FE model, were obtained from the Mentat Marc© software. The Von Mises stresses for both the cortical and the trabecular bone of the artificial and healthy knee FE model were analyzed and compared. The stresses that were obtained from the two knee prosthesis that were studied based on the artificial FE models were very similar to those stresses that were obtained from healthy FE models.

A feasibility study was performed in order to demonstrate the benefits of designing and manufacturing a customized foot orthosis by means of digital technologies, such as Reverse Engineering (RE), Generative Design (GD) and Additive Manufacturing (AM). The aim of this work was to define the complete design-manufacturing process, starting from the 3D scanning of the human foot anatomy to the direct fabricating of the customized foot orthosis. Moreover, this first methodological study tries to combine a user-friendly semi-automatic modelling approach with the use of low-cost devices for the 3D laser scanning and the 3D printing processes. Finally, the result of this approach, based on digital technologies, was also compared with that achieved by means of conventional manual techniques.

Aim of this work is to investigate the behaviour of a new reverse shoulder prosthesis, characterized by a humeral metaphysis with a variable offset, designed to increase the range of movements and to reduce the impingement. In particular, by means of virtual prototypes of the prosthesis, different offset values of the humeral metaphysis have been analysed in order to find the best positioning able to maximize the range of movements of the shoulder joint. The abduction force of the deltoid, at different offset values, has been also estimated. The study has been organized as follows. In the first step, the point clouds of the surfaces of the different components of the prosthesis have been acquired by a 3D scanner. This kind of scanner allows to convert camera images into three-dimensional models by analysing the moiré fringes. In the second step, the acquired point clouds have been post-processed and converted into CAD models. In the third step, all the 3D reconstructed models have been imported and assembled through a CAD system. After, a collision analysis has been performed to detect the maximum angular positions of the arm at different metaphysis offset values. In the last step, FEM models of shoulder joint with the new prosthesis have been created. Different analyses have been performed to estimate how the deltoid abduction force varies depending on the offset of the humeral tray. The study allowed to understand how the offset of the metaphysis affects the performances of the shoulder. The obtained results can be effectively used to give surgeons useful guidelines for the installation of these kinds of implants.

This work explores the use of an industry-oriented digital human modelling tool for the estimation of the musculoskeletal loads corresponding to a simulated human activity. The error in using a static analysis tool for measuring articulations loads under not-static conditions is assessed with reference to an accurate dynamic model and data from real experiments. Results show that, for slow movements, static analysis tools provide good approximation of the actual loads affecting human musculoskeletal system during walking.

This study uses the Finite Element Method (FEM) to analyze the influence of age, height and weight on the vertebrae and ligaments of the human functional spinal unit (FSU). Two different artificial segments and the influence of the patient’s age, sex and height were considered. The FSU analyzed herein was based on standard human dimensions. It was fully parameterized first in engineering modelling format using CATIA© software. A combination of different elements (FE) were developed with Abaqus© software to model a healthy human FSU and the two different sizes of artificial segments. Healthy and artificial FSU Finite Element models (FE models) were subjected to compressive loads of differing values. Spinal compression forces, posture data and male/female anthropometry were obtained using 3DSSPP© software Heights ranging from 1.70 to 1.90 meters; ages, between 30 and 80 years and body weights between 75 and 90 kg were considered for both men and women. Artificial models were based on the Charité prosthesis. The artificial prosthesis consisted of two titanium alloy endplates and an ultra-high-molecular-weight polyethylene (UHMWPE) core. An analysis in which the contacts between the vertebrae and the intervertebral disc, as well as the behavior of the seven ligaments, were taken into consideration. The Von Mises stresses for both the cortical and trabecular bone of the upper and lower vertebrae, and the longitudinal stresses corresponding to the seven ligaments that connect the FSU were analyzed. The stresses obtained for the two geometries that were studied by means of the artificial FE models were very similar to the stresses that were obtained from healthy FE models.

The cold expansion process is a technology that is widely used to enhance the fatigue resistance of aircraft metallic parts. The issue analysed in this paper concerns the case when the expansion is carried out through an assembly composed of several sheets. The numerical work conducted was intended to understand the phenomenology of the process within a stiff assembly. In particular, it aimed to analyse the deformation of the sheets and the residual stress fields generated by the process. For this purpose, an axisymmetric finite element model of the split sleeve process was developed, simulating a single expansion performed through a stack of two titanium holes (Ti-6Al-4V). The sheets to be expanded were positioned between two steel plates to simulate the assembly. The model could predict the shape and intensities of the fields within the expanded sections and their global outer shapes. We particularly focused on the phenomena prevailing between sheets. The simulation showed that deformations at the interface were greatly reduced when the stack was stiffened axially. Moreover, high circumferential and axial residual stresses were generated in the sheets. Results were compared with a single hole expanded without axial stiffening.

Air-cavity ships (ACS) are advanced marine vehicles that use air injection under hull to improve the vessel’s hydrodynamic characteristics. Although the concept of drag reduction by supplying gas under the ship’s bottom was proposed in the 19th century by Froude and Laval, at this time there are not many systematic studies on this subject. This paper is a preliminary work with the purpose of being a basic tool for the design of the ACS with computational fluid dynamic methods. The study aims to conduct a series of computational tests to compare the numerical models of bubble with experimental data. The first step of this study was to investigate the behavior of free bubble in water, considering as parameters the critical mass of air, the rising speed and aspect ratio of the bubble. Then it is evaluated the interaction bubble-flat plate in order to obtain a reliable prediction of the behavior of air bubbles under the hull.

This article focuses on improving the design methods for simplified models of screwed connections (spring, beam or bar elements), especially for the space sector. A detailed 3D model of a generic screwed connection has been developed using industrial finite elements (FE) software. An approach based on multiscale numerical designs of experiments (DOE) was used to obtain metamodels of stiffness and slip depending on geometric, material and contact parameters. In order to improve the integration of friction, an existing contact model was adapted and used to supply a modified Coulomb model. Metamodels from these numerical works were compared and correlated with experimental double shear tests on a specimen loaded by an imposed transverse displacement.

A 4.60 m sailing yacht, made with a flax fiber composite and wood, has been refitted with the aim of hull weight reduction and performance improvement during regattas. The first objective was obtained with a lightening of internal hull reinforcements while the second one with a reduction of the maximum beam, in order to minimize the longitudinal moment of inertia. The refitting was first simulated via CAD-FEM interaction to establish the feasibility of the procedure and to verify the structural integrity. The resulting hull was then instrumented with strain gauges and tested under typical rigging and sailing conditions. Results obtained by the numerical modeling and measured from experiments were compared.

Mesh morphing is one of the most promising approach for problems in which numerical analyses, based on discretised domains, involve shape parameterization. Some of the benefits associated to its adoption are the reduction of the computational meshing costs and the remeshing noise prevention, guaranteeing at the same time the continuum shape parameterization and consistency of mesh topology. One of the best mathematical tool to drive the mesh morphing (smoothing) task is recognized to be Radial Basis Functions. This paper introduce the RBF Morph tool and lists a set of applications in which the RBF shape parameterization is used to face problems ranging from aerodynamic optimization to Fluid Structure Interaction analyses.

A geometric tool for a catamarans sail plan and appendages optimization procedure is descripted. The method integrates a parametric CAD model, an automatic computational domain generator and a Velocity Prediction Program (VPP) based on a combination of sail RANS computations and analytical models. The boat performance is obtained, in an iterative process, solving the forces and moment equilibrium system of equations. Hull and appendages forces are modelled by analytical formulations. The closure of the equilibrium system is provided by the CFD solution of the sail plan. The procedure permits to find the combination of appendages configuration, rudders setting, sail planform, shape and trim that maximize the VMG (Velocity Made Good). A significant effort was addressed to the selection and evaluation of open-source tools to be adopted in the implementation of the method. The geometric parametric model, which is the core of the procedure, was object of particular attention. The FreeCAD geometric modeller was selected for this task. The sail shapes candidates are automatically generated, within the optimization procedure, by Python scripts that drive FreeCAD to update the geometry according to the variables combination. A very flexible model, able to offer a very wide space of variables, was implemented. This paper describes the implemented geometric model and the environment in which is included.

In this work, a multidisciplinary experience, aimed to study the permanent deformations of the hull of a regatta sailing yacht is described. In particular, a procedure to compare two different surfaces of the hull of a small sailing yacht, designed and manufactured at the University of Palermo, has been developed. The first one represents the original CAD model while the second one has been obtained by means of a reverse engineering approach. The reverse engineering process was performed through an automatic close-range photogrammetry survey, that has allowed to obtain very accurate measures of the hull, and a 3D modelling step by the well-known 3D computer graphics software Rhinoceros. The reverse engineering model was checked through two different procedures implemented by the graphical algorithm editor Grasshopper. The first procedure has allowed to compare the photogrammetric measurements with the rebuilt surface, in order to verify if the reverse engineering process has led to reliable results. The second has been implement to measure the deviations between the original CAD model and the rebuilt surface of the hull. This procedure has given the possibility to highlight any permanent deformation of the hull due to errors during the production phase or to excessive loads during its use. The obtained results have demonstrated that the developed procedure is very efficient and able to give detailed information on the deviation values of the two compared surfaces.

Mitigation of unwanted vibration is an important issue in aeronautics and space area. Since the emergence of innovative absorber Nonlinear Energy Sink (NES), more attentions were paid to this promising technique. This absorber is characterized by a secondary mass highly coupled via a nonlinear stiffness to the main structure that needs to be protected. The mastery of the nonlinearity is a key element for obtaining optimum performance for NES. However, it is difficult to implement cubic stiffness without linear part. In this paper, a novel design NES of cubic stiffnes without linear part is presented. For this, the two conical springs are specially sized to provide the polynomial components only with linear and cubic term. To counterbalance the linear term, a concept of negative stiffness mechanism is implemented by two cylindrical compression spring. A small sized NES system is developed. To validate the concept, the load-displacement relation test is performed, and simulation under period excitation and transient loading is studied. Future developments will aim experimental validation and application of the prototype.

In this paper, the main causes of technical malfunction of a hydrofoil was analyzed. In particular, a preliminary analysis evaluates the economic impact for the navigation company of the periodical maintenance related to the keeping of the vessel in dry dock. The study demonstrated that the main critical points are focused on the fragility of the stabilization control system. The increasing of operating costs has motivated the realization of a study aimed at redesigning the stabilization system. The continuing failure of the stabilization system (usually in water-immersed) severely limits the use of the high-speed craft. The proposed design solution considers the positioning of the control actuators of the flaps inside the hull. Therefore, a kinematic system constituted by a slider-crank mechanism that is driven by a double-acting hydraulic cylinder positioned above the waterline was studied and developed. In order to design the mechanical system, it was necessary to take into account of the critical factors related to the transmission of high torque loads with limited space available for the placement of the system components. In fact, in order to reduce the motion resistance and to optimize the hydrodynamic flows in the connection area of the wings to the central strut, it was necessary to design a double cardan joint of reduced radial dimension. Several numerical analyses conducted in ANSYS environment allowed to validate the proposed solution. Fatigue tests on an experimental prototype of the stabilization system allowed to ensure the integrity of the solution during the navigation.

Sail manufacture has undergone significant development due to sailing races like the America’s Cup and the Volvo around the World Race. These competitions require advanced technologies to help increase sail performance. Hull design is fundamentally important but the sails (the only propulsion instrument) play a key role in dynamic of sailboats. Under aerodynamic loads, sail cloth deforms, the aerodynamic interaction is modified and the pressure on the sails is variously distributed resulting in performance inconsistencies. The interaction between fluid and structure necessitates a solution which combines aerodynamic and structural numerical simulations. Furthermore, in numerical simulations the aeroelastic sail characteristics must be known accurately. In this paper, the dynamic performance of a Spinnaker was studied. Digital photogrammetry was used to acquire the images, make the 3D reconstruction of the sail and validate the models in Computational Fluid Dynamics (CFD) analysis. Orthotropic constitutive characteristics of ten different sail cloths were measured by experimental test. The methodology allowed to compare dynamic performance in terms of forces, pressure and vibration for the different sail cloths and different fiber orientations.

This paper introduces a Montecarlo Genetic Algorithm, hierarchical, multi-objective optimization of a Vertical Take Off landing Unmanned Aerial Vehicle having a tail sitter configuration. An optimization of the hierarchical type is introduced in place of the methods generally used multi-objective optimization, such as Pareto and “arbitrary” weighted sums. A Montecarlo method optimizes the weights of the final objective function used by the Genetic Algorithm. A very simple “spreadsheet based” algorithm defines the CAD model of the Genetic Algorithm individuals in order to evaluate the performance of the candidates. The optimization method described in this study appears to be very effective. Then experimental tests were conducted with scaled-down prototypes. Four flight tests were performed: Take Off, Cruise, Slow flight, Landing. A Taguchi matrix was defined for each experiment. The tests started from a prototype that comes directly from the Montecarlo Genetic Algorithm optimization and led to the final prototype shown along the paper (page 7, right figure). Unfortunately, the tail sitter approach proved poor control authority in the final phase of the vertical landing. Even the “final” prototype showed unsatisfactory behavior in case of erratic wind gusts. This unsolved problem is common to the tail sitter configuration that requires a power control by air jets or additional propeller to control the aircraft in the final phase of landing. Unfortunately, this necessity renders the tail sitter configuration inconvenient for small Unmanned Aerial Vehicles.

In the present work, by means of an integrated approach, a new rear suspension for motorcycles, able to achieve the required progressiveness in terms of rigidity by using a constant-stiffness spring and a compact mechanism, has been studied. The key component is an eccentric system inserted in the shock absorber head. As reference, we analyzed the rear suspension of the Ducati Multistrada MY 2010, characterized by the use of a variable-stiffness spring. The aim of the paper is to prove that the new proposed solution can obtain a response, in terms of load to the wheel, similar to that of the actual system. At first, a mathematical model to simulate the kinematics of the new suspension is presented. This model is able to evaluate the influence of geometric dimensions of the components, checking successfully the ability to reproduce the behavior of the original suspension. After the preliminary design, the kinematic and static models are included within an optimization algorithm ad-hoc created to calculate the exact dimensions of each component. Two Matlab/Simulink® lumped mass models, respectively referred to the novel and reference suspension, are used to compare the dynamic responses during the travelling of a particular road profile used in Ducati’s experimental tests. Finally, an accurate modeling of the components, considering also the production processes to be used for their creation, is provided.

Active noise control (ANC) methods have been successfully studied and tested for the cancellation of stationary noise. In the last decade, some adaptive solutions for the case of impulsive noise have been proposed in the literature. Nevertheless, such a model fits a limited class of impulsive disturbances that characterize practical scenarios. In this paper a preliminary study on the design of a non-adaptive deterministic ANC system for pulse signals that relies on no statistical assumptions is developed. The spatial audio rendering framework of Wave Field Synthesis is formally adopted in order to synthesize the cancelling sound field by means of an array of secondary sources. A set of preliminary simulations in free field environment, as well as the impact of array geometry and extension, has been carried out in view of forthcoming geometry and shape optimization of the system.

Integration of disassembly operations simulation during product design is an important issue today. A method for ergonomic evaluation of disassembly operations is presented here. It is based on three new criteria, presented by dimensionless coefficients: visibility score, neck score and bending score. The method is integrated in a Virtual Reality Disassembly Environment (VRDE) based on Python programming language using mixed VTK (Visualization Toolkit) and ODE (Open Dynamics Engine) libraries. The framework is based on STEP, WRL and STL exchange formats. The proposed method is tested and an example for disassembly sequences evaluation is presented. The results of the analysis and findings demonstrate the feasibility of the proposed approach thus providing significant improvement in Product Development Process (PDP).

This paper deals with a new simulation tool for the improvement of multi-robot pick & place applications performance combining behavioral simulation of multiple robots and products flows. A novelty of the proposed work is to take into account in the simulation not only the scheduling rules of each robot, but also the robots collaborative aspect to ensure the desired overall performance for a given task. The transition from simulation to implementation of pick & place strategies is also an issue tackled in this paper. By using a typical example consisting of comparing techniques to optimize the workflow, the utility of the simulation tool is proven. First experimental results validate the simulation results.

Along the cutting edge, the geometric and kinematic parameters vary greatly and the velocity vector at each point is very sensitive to the current position of the point considered on the cutting edge. The proposed study includes, for each of the three shear zones, the effect of velocity gradients on the strain fields and strain rates. These velocity gradients generate additional displacements of the chip, in three dimensions and, therefore, new force components and cutting moments. This study presents the overall approach for calculating cutting action starting with a detailed description of each feature area. The wrench of action is determined at the tip of the tool based on the elementary forces along the edge.

According to recent researches, it is desirable to extend Industrial Robots (IR) applicability to strategic fields such as heavy and/or fine deburring of customized parts with complex geometry. In fact, from a conceptual point of view, anthropomorphic manipulators could effectively provide an excellent alternative to dedicated machine tools (lathes, milling machines, etc.), by being both flexible (due to their lay-out) and cost efficient (20-50% cost reduction as compared to traditional CNC machining). Nonetheless, in order to successfully enable high-quality Robotic Deburring (RD), it is necessary to overcome the intrinsic robot limitations (e.g. reduced structural stiffness, backlash, time-consuming process planning/optimization) by means of suitable design strategies and additional engineering tools. Within this context, the purpose of this paper is to present recent advances in design methods and software platforms for RD effective exploitation. Focusing on offline methods for robot programming, two novel approaches are described. On one hand, practical design guidelines (devised via a DOE method) for optimal IR positioning within the robotic workcell are presented. Secondly, a virtual prototyping technique for simulating a class of passively compliant spindles is introduced, which allows for the offline tuning of the RD process parameters (e.g. feed rate and tool compliance). Both approaches are applied in the design of a robotic workcell for high-accuracy deburring of aerospace turbine blades.

Indirect estimation of the stiffening effect caused by the fitting process of an automotive wheel is hereby presented to detect optimal interference of automotive steel wheels. The effects are related to components and assembly characteristics, such as masses and natural frequencies. Both the components of the wheel, which are disc and rim, are subject to generalised tolerances and uncertainties, mainly related to elasto-plastic material properties, dimensional and geometrical tolerances and manufacturing process parameters. Taking into account the theoretical change in the dynamic properties of a pre-stressed structure with respect to its non-stressed condition, the stiffening effect caused by the fitting process is expected to bring consequences on the natural frequencies of particular and representative modes of the assembly. Moreover, the dynamic behaviour of the assembly can be related to the one of the two separate components, in order to improve the indirect estimation of the pre-stressed condition. The methodology is developed starting from numerical and experimental modal analysis, building a meta-model based on these training data, then evaluating the performance of that on a production wheel case. The optimal interference fit estimations are tested on a standard steel wheel for the Iveco Ducato commercial vehicle. Then to evaluate the robustness of the method, the meta-model is used for a compact spare tyre of a saloon car.

This work describes an integrated method of 3D modelling algorithms with a modal approach in a multibody environment which provides a slimmer and more efficient simulation of flexible component contacts realistically reproducing system impacts and vibrations. A non-linear numerical model of the impulse contact forces based on the continuity approach of Lankarani and Nikravesh is developed. The model developed can evaluate deformation energy taking into account the material’s characteristics, surface geometries and the velocity variations of the bodies in contact. ADAMS®-type modelling is applied to the sliding contacts of the links of a chain and its mechanical tensioner (“blade”) in the timing of an internal combustion engine. The blade was discretized by subdividing it into smaller components inter-connected with corresponding centres of gravity through 3D General Forces. Static and dynamic tests were performed to evaluate the stiffness, damping and friction parameters for the multibody model and to validate the methodology.

The numerical technology for modelling and simulation, whose the rise in power has followed computer science evolution, has become increasingly used from the beginning of V-model in the field of systems engineering and product development. As a matter of fact, numerical simulation allows a reduction in costs and lead times by avoiding or limiting the physical prototyping. In this paper, the proposed work deals with the design aid to meet requirements, modelling, analysis and simulation of a component assembly constituting a hydraulic power transmission taking into account the fluid borne. This paper establishes first the aid for architecture design, their analysis and optimizations to meet the different requirements. Among the different kinds of requirements that a hydraulic circuit have to meet, this paper focuses especially on the fluid borne noise and the noise generated during the operation. Therefore, in the section 3 is presented a state-of-the-art on the fluid borne noise modelling in frequency domain applied in different hydraulic components and also on test rig which are used to adjust certain parameters of hydroacoustic laws. Finally, the last part of the paper focuses on the different computer tools and simulation software which are used to model hydraulic circuit taking into account hydroacoustic and vibroacoustic phenomena. Thus, this part also discusses how they are interfaced with each other and which kind of information has to be exchanged in order to obtain a relevant modelling and simulation for wave propagation in temporal domain.

This paper proposes a way to perform the study of an ancient machine from the viewpoint of the industrial archeology. The methodology is based on a number of steps and a schema to conduct the study, supported by a simulation of the machine. This approach is illustrated by its application to an ice-making machine of the nineteenth century. The ice-making machine is the one developed by Linde in 1880. Once it is finished, this type of studies and analysis may be very significant for any student or researcher that wants to understand the basis of this technology.

In the last decades the main focus for improvements in Power Electronics was mainly addressed on chip technology. Therefore, Power Electronic performance depends by a high ratio on package technologies and on their interconnections. In particular, the automotive industry has high requirements regarding cost efficiency, reliability and compactness. Increasing power densities, cost pressure and more stringent reliability target for modern power semiconductors are making thermal system optimization more and more important in relation to electrical optimization. This article will give an overview of the new methodological approach leaded by Finite Element (FE) simulation for new packages and interconnection solution ideas. A viscoplastic creep modelling is adopted for the solder taking into account time, temperature and stress dependences in Thermal Cycle. A parametric study is performed by changing geometrical solutions. The results obtained from the modelling has been used to form design guidelines that were also matched with experimental data.

Virtual reality techniques have been used since several decades ago to complement the three dimensional modelling in engineering and other disciplines. This technology allows engineers to view their projects into a 3D environment helping to better understand the different designs and bringing a new perspective of them, and also to simulate different states of the construction process. When assessing the visual impact of a wind farm, the use of virtual reality scenery can help the designer to integrate the visual aspects in the planning process and to show the changes produced in the different views. Also, it is a very powerful communication tool that provides an effective way of presenting the visual impact, as well as to understand and imagine the future landscape for the stakeholders.

The study of the methodologies useful to support the assembly of parts is a challenging engineering task which can benefit of the most recent innovations in computer graphics and visualization technologies. This paper presents a proposal for an innovative methodology based on Virtual and Augmented Reality useful to support the components’ assembly. The herein introduced strategy is based upon a four stages procedure: at first the designer conceives the assembly sequence using a CAD system, visualizing the scene wearing an immersive Virtual Reality device. In the second stage, the same sequence is developed by an unexperienced user using the same equipment: the differences between two assembly sequences are recorded and exploited to detect critical points in the assembly sequence and to develop a Knowledge Based System. Finally, a virtual user manual is produced in Augmented Reality. When the final user uses the tool, the position of the object to assemble is detected by tracking the finger position of the user itself. A series of symbols and writings is added to the external scene to help the end-user in the assembly procedure. A test case based on the assembly of a scale model has been developed to evaluate the methodology. After an evaluation process, the procedure seems to be feasible and presents some advantages over the state-of-the-art methodologies proposed by literature.

Spiral Bevel gears are used in power transmission systems with two crossed shafts. The topic of the paper is a model for helping the spiral bevel gear design, depending on meshing parameters. The global parameters of the gear are calculated with the standard ISO 23509 equations. A prediction of the profile modifications has also been performed to center the load pattern on the flank and to minimize the maximum contact pressure. A numerical simulation is achieved with the ASLAN software, developed by LaMCoS laboratory for calculating the quasi-static load sharing of spiral bevel gears.

3D face was recently investigated for various applications, including biometrics and diagnosis. Describing facial surface, i.e. how it bends and which kinds of patches is composed by, is the aim of studies in Face Analysis, whose ultimate goal is to identify which features could be extracted from three-dimensional faces depending on the application. In this study, we propose 54 novel geometrical descriptors for Face Analysis. They are generated by composing primary geometrical descriptors such as mean, Gaussian, principal curvatures, shape index, curvedness, and the coefficients of the fundamental forms. The new descriptors were mapped on 217 facial depth maps and analysed in terms of descriptiveness of facial shape and exploitability for localizing landmark points. Automatic landmark extraction stands as the final aim of this analysis. Results showed that the newly generated descriptors are suitable to 3D face description and to support landmark localization procedures.

A geometric modeling of Agustin de Betancourt’s plunger lock with the parametric Autodesk Inventor Professional 2016 software has been obtained, which has made it possible to get a simulation of movement, as well as perspectives and exploded views. The process of geometric modeling has followed several steps: First, the only available mapping has been only a couple of unscaled sheets found in several documents. These are accompanied by a report on which parts of the plunger are detailed, the dimensions of some parts and the purpose of the joint, allowing a first approach to the reconstruction of the plunger lock as conceived by Betancourt. Also, some dimensional hypothesis that the engineer does not specify while considering the design has been done, such as transmitting motion to the shaft which gives the counterweight raising and lowering the diver and the dimensions of shafts and gears (with the gearing for transmitting the motion of the crank shaft of the counterweight). The main contribution is that for the first time the sub-system of the counterweight (gears, pulleys, girder bridge, chains, mobile counterweight and tilting counterweights) has been dimensioned to always achieve the equilibrium position between the movable counterweight and the plunger, independent of the part which is outside the water. This unprecedented research values one of Betancourt´s main contributions to civil engineering which provided a real solution to the problems of navigation canals of the French rivers in the early nineteenth century and was highly valued by the French Academy of Sciences.

Stirling engines have become of great interest on the last decades due to their efficiency and sustainable energy production. This study develops one of the first phases of the design of a Stirling beta type engine - able to generate 1kW of power- including the specification of basic components of the engine and a thermodynamic simulation (by Computer Fluid Dynamic-CFD) with real parameters. The approach comprises thermodynamic improvements of the engine, which are the base for an improved design. The methodology consists of various consecutive steps such as design procedures, theoretical calculations, simulation process description and analysis of results obtained. The first phase defines the model geometry, specifying the volume occupied by the working gas, equations that define the power and shifter pistons movements and dimensions of all components that perform the engine. After defining the inner volume, the mass of gas inside the engine is calculated, and hypothetical contour conditions are established. Based on these data and following the theoretical ideal engine process, it is possible to obtain the theoretical P-V diagram, as well as the engine power and efficiency through a basic thermodynamic analysis. This procedure is repeated as many times as needed in order to get the desired results. By modifying different parameters, it is possible to find a suitable design that combines geometry and contour conditions, and therefore approach to the design power.

In orthopaedics, cellular structures can be used as three-dimensional porous biomaterials that try to mimic the characteristics and function of the bone. The progress in manufacturing techniques, mainly in the field of additive manufacturing, can potentially allow the production of highly controlled pore architectures and customized implants that, however, need more sophisticated design methodologies. In this paper, the design of porous biocompatible structures based on mathematically defined surfaces (triply periodic minimal surfaces) has been considered in respect of the approach that considers unit cells entirely modelled in CAD environment. Two types of unit cell have been here considered: the cubic and the P-cell. The cubic cell is created by a 3D CAD s/w from solid features that are combined together. The P-cell is modelled using an implicit function to describe the outer surface of the cell. Two are the design parameters of the P-cell: thickness and radius. The variation of these parameters allows modifying the architecture of the basic unit of the scaffold. The modification of the radius is carried out by a procedure, based on scaling and truncation operations. The thickness of the cell is modified by thickening and closure operations on the P-isosurface. The effect of these variations on the mechanical behaviour of the scaffold has been numerically evaluated by the estimation of the stiffness of each structure considered. The results demonstrated the huge potentiality of the method and stiffness values compatible with those required for biomechanical applications.

The complexity of the heterojunction organic solar cell stems from the delicate balance that exists between the different properties of the materials used and the geometric structure of the cell itself. Therefore several parameters affect the solar cell conversion efficiency. For this reason, in the literature there are a large variety of optimization techniques in order to improve the conversion efficiency of solar cells. Often these optimization techniques are complex and costly. In this paper, a back propagation neural network is used to disclose the link between length and the maximum power output of the device. The simulation results obtained show that the devices length has a great influence on the their efficiency and therefore must be taken into account in manufacturing processes.

This paper proposes a review of the methods to detect and represent the human symmetry line. In the last years, the development of 3D scanners has allowed to replace the traditional techniques (marking based methods) with modern methodologies that, starting from a 3D valid discrete geometric model of the back, perform the posture and vertebral column detection based on a complex processing of the acquired data. The purpose of the paper is a critical discussion of the state of the art in order to highlight the real potentialities and the limitations still present of the most important methodologies proposed for human symmetry line detection.

The reuse of damaged stamps or forgingc dies is a key aspect of the forging process. Whenever a forging die must be repaired the damaged zones are filled with welding material to be later machined. In this process, some phases can be optimized as the amount of welding material and moreover the machining tool paths and parameters. With the introduction of new digitization technologies new possibilities in the automatization of the machining are arisen. Thanks to the application of reverse engineering techniques, good and smoothed contours are extracted from the digitized geometry. The machining phase based on the obtained contours is considerably reduced in time and it does not involve any significant problem. The obtaining of these contours is the most complicated step of the proposed methodology. Some tests with diverse forging dies and mixed contours have been performed. The operations defined in this paper perform in an optimal way in all the cases. The repairs are analyzed and the required times in the actual and the proposed processes are compared.

Body scanning presents unique value in delivering the first digital asset of a human body thus resulting a fundamental device for a range of applications dealing with health, fashion and fitness. Despite several body scanners are in the market, recently depth cameras such as Microsoft Kinect® have attracted the 3D community; compared with conventional 3D scanning systems, these sensors are able to capture depth and RGB data at video rate and even if quality and depth resolution are not optimal for this kind of applications, the major benefit comes from the overall acquisition speed and from the IR pattern that allows poor lighting conditions optimal acquisition. When dealing with non-rigid bodies, unfortunately, the use of a single depth camera may lead to inconsistent results mainly caused by wrong surfaces registration. With the aim of improving existing systems based on low-resolution depth cameras, the present paper describes a novel scanning system for capturing 3D full human body models by using multiple Kinect® devices in a compact setup. The system consists of an instantaneous scanning system using eight depth cameras, appropriately arranged in a compact wireframe. To validate the effectiveness of the proposed architecture, a comparison of the obtained 3D body model with the one obtained using a professional Konica Minolta Range Seven 3D scanner is also presented and possible drawbacks are hinted at.

This paper aims to provide a road map for future works related to reverse engineering field of expertise. Reverse Engineering, in a mechanical context, relates to any process working in a bottom-up fashion, namely that it goes from a lower level concept or product (closer to the final product) to a higher level one (closer to the ideation step). Nowadays, the manufacturing industry is facing unprecedented increase in data exchange and data warehousing. This comes with new issues that our work will not explore, such as “how to store these data in an efficient manner?”, “what should be stored?” and so on. Nonetheless, this trend also creates new opportunities if we manage to integrate these data into the expertise workflows. In this paper we will cover the possibilities offered by machine learning to succeed in this challenge. We will also present a first and major step in our road map in order to achieve our research goals. We plan to design a metric to quantify how well and how precise can we perform some specific reverse engineering tasks such as detection, segmentation and classification of mechanical parts in imagery data. We aspire to open this metric, and make it freely and widely available to researchers and industry in order to compare the effectiveness, robustness and preciseness of the existing and future approaches.

This paper presents a brief review of recent methods and tools available to designers to perform reverse engineering of CAD models starting from 3D scanned data (mesh/points). Initially, the basic RE framework, shared by the vast majority of techniques, is sketched out. Two main RE strategies are subsequently identified and discussed: automatic approaches and user-guided ones.

Distributed systems spread widely in industrial environments. One of the key challenges is the exchange and the aggregation of data between these systems. Although standards play an important role to solve data interoperability issues between systems, these standards do not completely address existing industrial problems. In fact, it is not granted to have an industrial environment that complies with a unique standard; therefore, ad-hoc solutions are used to solve this issue. In this article, the authors propose a generic architecture to address the interoperability between systems. This architecture is developed based on model-based techniques and principles. Besides, it reduces the need for human intervention and time by developing once and reusing the building blocks of the architecture. Finally, the architecture is described in its application to a case study.

In New Product Design process, CAD Model is used in design meetings to help design actors in their collaboration. However, it is important to prepare digital mockups to be more effective in design meetings. Thus, we introduce in this paper an approach to prepare CAD model for collaborative design meetings supported by a self-developed CAD add-on. The proposed approach is based on parametric modelling of CAD model and involves two key steps: a) automatic transfer of Functional Requirements to CAD model and b) preparing design configurations and validation reports for collaborative design meetings. Our approach was implemented through the development of the CAD add-on in a commercial CAD system environment.

The medical sector is a wide and complex field that needs continuous improvements in its efficiency. This paper deals with the problem of collaboration and the data sharing in the medical field. The focus is on the case of treatment processes requiring prosthesis implant. Several actors from both medical and industrial sectors are involved in these processes. They need to collaborate during the whole process of prosthesis creation and implantation. From this perspective, this paper presents a discussion about the advantages of the current PLM-based approaches to deal with these issues. A first proposal of the conceptual approach is also proposed.

In the present study, the potential use of unmanned aerial vehicles (UAVs) as a platform to flexibly obtain sequence of images along coastal areas from which producing high quality SfM-MVS based geospatial data is tested. A flight campaign was conducted over a coastal test site covering an area of around 4 has near Malaga (Spain). Images were taken on 1st December 2015 at a height above the ground ranging from 113.5 to 118 meters by using a Sony α6000® consumer camera mounted on a UFOCAM XXL v2® octocopter. 40 RTK-GPS surveyed ground points were evenly distributed over the whole working area. Furthermore, a very dense and accurate point cloud was collected by using a FARO Focus 3D X-130 terrestrial laser scanner (TLS). The photogrammetric block was computed by using two widely known SfM-MVS commercial software implementations such as Inpho UASMaster® and PhotoScan Professional®. PhotoScan provided a highly accurate bundle adjustment with errors of 1.5 cm, 1.5 cm and 6.1 cm along X, Y and Z axis respectively. The triangulation errors computed from UASMaster turned out to be slightly poorer along Z axis. In this sense, the very high resolution Surface Model built up from the corresponding photogrammetric point cloud depicted higher Z-differences with respect to the reference TLS derived surface model in the case of the UASMaster workflow. Summing up, the high degree of automation and efficient data acquisition provided by UAV-based digital photogrammetry makes this approach competitive and useful to be applied in high resolution 3D coastal mapping.

Indoor path planning in a building means determining a short practicable route between two distant inner spaces, through other spaces and passages such as doors or stairs, while avoiding collisions against obstacles like walls or equipment. This paper presents an original indoor path planning method called BiMov, based on a BIM (Building Information Model). The analysis process involves several phases. First, all the possible indoor paths across the containers (spaces) are algorithmically determined based on a BIM represented by an IFC (Industry Foundation Classes) file, which characterizes a rather stable situation. In a second phase, the number of paths is potentially reduced depending on the kind of MOoP (Mobile Object or Person) considered, that can be a person, disabled or not, a handling machine, a mobile robot, or a bulky equipment. In a third phase, the paths within the spaces are possibly refined, depending on their contents, which may be affected by the presence of machinery or restricted areas. In a fourth phase, the number of paths is again optionally reduced, depending on the real-time or planned status of the building’s spaces and passages, i.e. whether they are conjuncturally accessible or not. The paper will emphasize phases one and two.

This work present some best practice cases in teaching technical drawing done by three Italian Universities: Brescia, Udine, and Cassino and Southern Lazio. The intention to innovate and improve the basic technical drawing courses offered by these three Universities started in 2014. The objective of this collaboration was the development of some tools to help the students in understanding the fundamental concepts of technical drawing. The first tool developed, in order of time, was the Technical Drawing Evaluation Grid – TDEG. Starting from this tool, other learning aids were developed for the undergraduate engineering students. Some of them are: an online test for students’ self-assessment of technical drawing knowledge; a questionnaire to collect students’ opinions on different technical drawing and engineering design topics; a method for the improvement of students’ motivation to study; and a self-learning tool for teaching manufacturing dimensioning. The preliminary results of these different practices are presented and discussed in the following, posing the basis of the definition of some best practice methods that can be used for the improvement of the teaching and learning of technical drawing basic concepts for engineering students.

Even though engineering is a vocational degree, students need to be stimulated so that they are more participative and active. New pedagogical methodologies have been proposed to inspire and motivate students while training to become professionals in the engineering field. One of them, gamification, is based on the use of game design elements in non-game contexts, like learning environments. Several studies have dealt with the use of gamification in engineering courses, 87% of them reporting that their implementation had some degree of positive outcome. This paper shows the experience of game-based learning applied to a Graphical Engineering course in the second year of the Mechanical Engineering curriculum at a Spanish university. Several activities were developed during the academic course, in which students had to face different kind of tasks: competitions, simulations, research tournaments, pokes, social forums, survey games, etc. As participation was voluntary in most cases, the current study is focused on the individual perception of the students, rather than on the overall learning outcomes of the group. The results of this experience based on “Learning by playing” have been positive, according to lecturers and students’ perception. The number of students considering the game-based activates as beneficial or entertaining is between 3 to 10 times higher than those who think the opposite. The main advantages of gamification have been, thus, increasing the attending ratio of the class, enhancing the interest for the topics of the lectures, bringing fun and joy to the classroom and giving more initiative to the students.

In Engineering Schools is a growing concern to offer its students the latest in 3D CAD modeling software that respond to advanced design needs. The latest software is increasingly comprehensive and complex. However, the time available for teaching such software is scarce and rarely get to know more than 20% of the potential of the software for a particular area. However, other 3D CAD solutions are on the market, low cost, very friendly, easy to learn interface, with much potential and you will get to have all the features of more advanced software, can fully meet the teaching requirements this area. Since the introduction of the EHEA (European Higher Education Area), the target level of teaching an engineering school in the field of 3D CAD modeling, should be to develop in students in the time available, the maximum capacities and skills three-dimensional geometric design. And this, when well planned, can be achieved with the proper use of low cost software. The authors have analyzed the potential of various freeware or shareware software, well suited to the typical subjects of Engineering Design, in the areas of CAD-3D design and rendering.

In the medical field, Assistive Technologies (AT) are one of the most dynamic due to the evolution of the population (elderly and disable people). Dedicated products are complex to design and to manufacture because of the end users’ specificities and particularities. The integration of multiples competencies in the design process are necessary to be able to define a complete list of requirements. This collaborative work with the involvement of the end user necessitate a reflection about the design method. Statistics of products abandonments illustrate the difficulty for companies to create a favorable working environment taken into account multiple parameters from various expertise. Based on these states of difficulties, the present study aims to develop an interdisciplinary experimented teaching situation focused on the use of Rapid Prototyping. The AT field has been chosen to develop this design process teaching. The favorable pedagogic context takes place in the Industrial Department of the Federal University of Paraiba. The proposal was to implicate several departments from this university to organize a complete course with the objective to teach Interdisciplinary in graduation level in the university: the initial idea was to give all necessary resources to the groups of students (two types of progressive workshop during the course); they choose the ones that are necessary to design and prototype something adapted to the user’s requirements.

The aim of this paper is to put across one of the work lines developed by the research group of Graphic Engineering and Design. A work oriented to rescue and recover our industrial past through heritage retrieval that might be achieved virtually or, physically when possible (buildings, machines, files, etc.), by students of Design and Mechanical Engineering. This retrieval is performed not only from the real state perspective but, as the National Plan of Industrial Heritage indicates, focusing as well in movable property such as devices, tools and files, and most especially in machines, without disregarding intangible assets such as testimonies and institutions that could help retrieve our magnificent industrial past. This work is understood as vital from a double perspective: Cultural heritage tourism and Engineering students practice. A study of movable properties such as machines, tools and files related to the ancient industries located in Malaga is presented here. Those movable properties that once made Malaga one of the first most industrialized cities in Spain and are now included in the project called REVIMAQU that drives Malaga’s industrial heritage revival.

In the present times companies demand professional skills from the candidates, desirable attitudes and values that go beyond knowledge and skills. In order to provide students with an experience that encourages the development of these kind of profiles, it has been proposed a service learning project in collaboration with public funded business incubators where the students could meet real customers whose businesses are within creation processes. This paper shows the experience of the students of Industrial Design and Product Development Engineering Degree at the University of Zaragoza challenged to fill a need (by social request), while studying Graphic Design and Communication. The students evaluation reveals that it has been a positive and enriching experience. Such initiative is transferable to other studies degree to increase student motivation and involvement and enhance the image of a socially committed university. Entrepreneurs have assessed the experience as helpful to show students the companies’ needs, facilitating the University to approach business’ environments as well as to provide an image of the Degree open to the society.

Industrial design is today, a key factor for business success, as well as an essential formula to compete in the market. This is one of the reasons why today, there is a great demand for professionals with knowledge in mechanical engineering and industrial design. By contrast, in engineering studies, much time is spent on training in CAD, in order to have an advanced knowledge of design tools, leaving aside the analysis of whether the designs will be good or not from the point of view of the customer. Many of these engineering students will be professional designers in the future designing their own products and being able to create a company that made designs that would have to be customer focused. In this context there has been carry out, several activities in the course of graphic engineering techniques in the degree of mechanical engineering in third year of this studies. The subject has been raised with an applied approach to the professional market, making creative products, including the functional aspect and customer focus, issues of vital importance but neglected by educational programs. In this research, a professor of marketing, with a great professional experience in patent pending, has taught several classes at the beginning of the subject related to how to conduct interviews with the client to identify their needs, with the aim to give the initial design requirements by the customer. The result of the experience has resulted in a set of designs of higher quality than those made in previous years.

In previous work on the axonometric perspective, the authors presented some graphic constructions that allowed a single and joint invariant description of the relations between an orthogonal axonometric system, its related orthogonal views, and oblique axonometric systems associated with it. Continuing this work and using only the items drawn on the frame plane, in this communication we start from the three segments, representing trirectangular unitary thriedra, joined in the origin and defining an axonometric perspective. Each is projected onto any direction and the square root of the summa of the squares of these projections is determined. We call this magnitude, orthoedro diagonal whose sides would be formed by the three projections axonometric unit segments. If the diagonal size is built from the origin of coordinates and onto the direction used, this describes a locus here called intrinsic curve associated with the ellipse. When the starting three segments represent an orthogonal axonometric perspective, the intrinsic curve associated with the ellipse is a circle.

It is known that the axonometric defined by Pohlke, is geometrically known as a means of representing the figures of space using a cylindrical projection and proportions. His theorem says that the three unit vectors orthogonal axes of the basis in the space can be transformed into three arbitrary vectors with common origin located in the frame plane. Another way of expressing this theorem is given in three segments mismatched and incidents at one point in a plane, there is a trirectangular unitary thriedra in the space that can be transformed in these three segments. This paper presents a graphical procedure to demonstrate a solution of Pohlke’s theorem. To do this, we start from previous work by the authors on the axonometric perspective. Graphic constructions that allow a single joint invariant description of relationships between an orthogonal axonometric oblique axonometric system and systems associated thereby. At a same time of the geometric locus generated by the diagonal magnitude positioned at any direction in the plane of the picture. This magnitude is the square root of the sum of the squares of the projection of the three segments representing axonometric on arbitrary magnitude.

The functional tolerancing of hyperstatic mechanisms provides contractual documents established following the ISO tolerancing. The tolerancing methodologies consider that the mechanism is infinitely rigid. These mechanisms impose tight clearances to ensure the functional requirements and parts fittability. The proposed methodology consists in developing a mechanical model relating the tolerances obtained by traditional methods of geometrical tolerancing and the parts deformability to define the tolerance values of the geometrical specifications. The first step is to define the geometrical specifications with ISO tolerancing. The fittability between two parts in contact requires maximum material conditions. The functional requirements employ least material condition. The second step consists in defining the capacity of parts to deform taking the tolerance values into account. A mechanical model is described relating the parts deformability to the tolerances to guaranty the conformity of the functional requirements and assembly parts fittability. As a validation example, the proposed methodology is used on a hyperstatic mechanism composed of two subassemblies: an outer tube and a shaft made of several assembled sections.

Our approach in tolerance analysis of a mechanical system is based on the use of sets of constraints. These operand sets model the geometrical variations between two surfaces of the same part or between two surfaces of distinct parts potentially in contact. They are 6-dimensional polyhedra, 3 variables modelling the translation and 3 others the rotation. In order to compute the cumulative stack-up deviations between any couple of surfaces, we need to bound these polyhedra making polytopes out of them to run 6d Minkowski sums. Checking the validity of the geometrical tolerances is the result of a process involving Minkowski sums (modelling the propagation of the geometrical defects in a series through the mechanical system) and intersections (simulating multiple contacts between different parts). However, adding artificial bounding facets or cap half-spaces, can turn out to be far too expensive because their number skyrockets as a consequence of the accumulation of the degrees of freedom. So we trace all the facets of the polytopes through the computation process to be able to distinguish between the relevant information, for the tolerance analysis, and the capped one. Keeping such a complexity under control results in a very significant saving of computation time and memory space. In the second part of the paper, we apply our approach to an industrial case to demonstrate its efficiency on a real-life mechanical system. As no restrictive assumption on the contacs between parts have to be made, our method is perfectly suitable for over-constrained mechanical systems.

The tolerances of welded chassis are usually defined and adjusted in very expensive trials and errors on the shop floor. Computer Aided Tolerancing (CAT) tools are capable to optimize the tolerances of given product and process. However, the optimization is limited since the manufacturing process is already mostly defined by the early choices of product design. Therefore, we propose an integrated design method that considers the assembly operations before the detail design of the chassis and the concept design of the fixture system. The method consists in four phases, namely functional analysis in the CAD environment, assembly sequence modelling in the CAT tool, Design Of Simulation Experiment on the stack of the tolerance ranges and finally optimization of the tolerances. A case study on a car chassis demonstrates the effectiveness of the method. The method enables to selectively assign tight tolerances only on the main contributors in the stack, while generally requiring cheaper assembly operations. Moreover, a virtual fixture system is the input for the assembly equipment design as on optimized set of specifications, thus potentially reducing the number of trials and errors on the shop floor.

Understanding geometrical specifications is becoming more and more difficult due to the latest developments in ISO GPS (Geometrical Product Specification) Standards, and at the same time, students’ learning habits are evolving and theoretical courses on standardized specifications are not attractive. Metrology laboratory work is much more appealing and highlights the difficulties encountered in interpreting specifications and the inherent method uncertainties. Nevertheless, metrology activities require an expensive metrology laboratory equipped with CMMs. In order to carry out real hands-on experiments, Bordeaux University is designing a virtual laboratory framework. It is integrated into Moodle (an L.M.S., Learning Management System) as a new activity to establish a link with other Moodle learning activities (courses, tests, etc.) and to ensure student tracking. A first prototype of the virtual laboratory is dedicated to dimensional and geometrical metrology with simulated traditional measuring devices (gauge, micrometer, dial indicator, etc.) and Coordinate Measuring Machines. Measurement simulation is in a three-dimensional environment and is based on models of parts with dimensions, orientation, position and form errors (skin model shapes) and on models of measuring devices with measurement uncertainties.

This paper presents a new methodology whose goals are on the one hand the formulation of a tolerance specification that is consistent with the functional, technological and control needs and, on the other, the automatic control of tolerance. The key aspect of the methodology is the digital model of the product, referred to as GMT (Geometric Model of Tolerancing), which gives a complete, consistent and efficient description of its geometrical and dimensional properties with the aim of being able to specify, simulate, manufacture and inspect them. By means a real test case, the potentialities of a first implementation of the proposed methodology are critically discussed.

A new method for secondary features segmentation, performed in high-density acquired geometric models, is proposed. Four types of secondary features are considered: fillets, rounds, grooves and sharp edges. The method is based on an algorithm that analyzes the principal curvatures. The nodes, potentially attributable to a fillet of given geometry, are those with a certain value for maximum principal curvature. Since the deterministic application of this simple working principle shows several problems due to the uncertainties in the curvature estimation, a fuzzy approach is proposed. In order to segment the nodes of a tessellated model that pertain to the same secondary features, proper membership functions are evaluated as function of some parameters, which affect the quality of the curvature estimation. A region growing algorithm connects the nodes pertaining to the same secondary feature. The method is applied and verified for some test cases.

Multiple modal decomposition of surfaces methods are increasingly used to analyse the typical geometric defects of manufactured surfaces. According to the context, this decomposition can either be done on a base which is known a priori (e.g. Discrete Cosine Transform, natural vibration modes etc.) or on a base that is identified from a set of measured surfaces (i.e. manufacturing dependent “technological modes” using the Principal Components Analysis or Independent components analysis). In this paper, a set of simulated surfaces are generated by linear combination of a given typical defect set in order to compare the efficiency the two different techniques. The compared techniques are, 1) methods founded on an a priori base and, 2) multivariate analysis methods (The key modes are identified for each method and compared to the technological modes used to generate the trial surfaces. From this study it may be concluded that while the first method does not allow the identification of the technological modes, the second does provide possible insight into the production technologies.

During sintering, porcelain changes its phase composition as well as its physical and mechanical properties. The most evident effect of these transformations is a significant change of shape, which is a combination of shrinkage and pyroplastic deformations, caused by softening. Both of these phenomena are induced by temperature, which is on its turn influenced by several variable factors that are difficult to predict. Especially for products manufactured in large scale, the resulting shape of artefacts may significantly vary even among the same batch. Consequently, for companies demanding high quality standard, this variability entails a high number of rejected products. For this reason, the present work aims at investigating the amount of variation introduced by firing process for an actual industrial product, independently from other (more or less) known variation sources such as the ones related to materials and forming processes. This could help process engineers to focus their attention when trying to improve the quality of final products.

The paper is intended to propose a method to characterize the adhesion of a thermoplastic matrix composite material that is reinforced with continuous fibers and over-injected vulcanized rubber. The behaviour of the material based on the thermoplastic matrix and the adhesive is studied. In addition, the combination of factors that provides the greatest possible adhesion of the rubber to the composite is analyzed. Test methods are also analysed and suggested to characterize the adhesion force of the vulcanized rubber to the thermoplastic composite.

The paper presents a study defining the geometry of product packaging and its graphics applications. This methodology is based on the analysis and segmentation of existing products present in the market. The case presented focuses on eye contour creams packaging present in the Spanish market, but the study methodology can be transferred to any other product packaging, both in the field of cosmetics and in any other sector. The segmentation has been made based on product range, and has led to detecting types of packaging, color, opacity, graphic applications with typographies etc. characteristic for each range. The results show that multiple variables differs products packaging belonging to different ranges and that it is possible to design packaging type characteristic for each price segment. The conclusions drawn from the application of this methodology could be used by cosmetic companies for adjusting the presentation of their products according to their market positioning.

During recent years the European Ecodesign Directive has introduced big changes in the design methodology of several energy-using products including consumer goods such as ovens, washing machines and kitchen hoods. Additionally, the introduction of the Energy Labelling Directive pushes manufacturers to implement new energy-saving features in many energy-related products sold in Europe. As a consequence, several companies have been encouraging the improvement of their energy using products paying attention to the related selling cost. Eco-driven products require eco-design tools to support the eco-innovation and the related sustainability improvement. The main scope of the proposed research is the reduction of the time-to-market for the energy-using products such as kitchen hoods. In this context, the paper aims to provide an approach to support a pre-evaluation of the energy labeling related to kitchen hoods. A prototypical software tool has been developed in order to simulate the energy performance of new kitchen hood configurations in term of energy efficiency. The approach also considers the introduction of virtual experiments in order to calculate the performance of virtual modules. This tool makes the product-engineer more aware in the decision-making about the energy-saving. As a test case, different product configurations have been compared analyzing the energy labelling and the overall energy performance.

Cost Estimation for offer generation in ETO companies is a critical and time-consuming activity that involves technical expertise and a knowledge base. This paper provides an approach to acquire and formalize the design and manufacturing knowledge of a company. The method has been described as a sequence of steps, which moves from the data acquisition of the past projects to the definition of a cost function based on dimensioning parameters. This approach has been experimented on a family of cranes for plants in collaboration with an industrial partner.

Nowadays, in customer/supplier relationship, suppliers have to define and evaluate some offers based on customers’ requirements and company’s skills. This offer definition implies more and more some design activities for both technical solution and its delivery process. In the context of Engineering-To-Order, design and engineering activities are more important, the uncertainties on offer characteristics is rather high and therefore, suppliers bid on the calls for tender depending on their feelings. In order to provide suppliers with metrics that enable him/her to know about the confidence level of an offer, we propose a knowledge-based model that includes four original metrics to characterize the confidence level of an offer. The offer overall confidence relies on four indicators: (i) two objectives ones based on Technology Readiness Level and Activity Risk Level, and (ii) two subjective ones based on the supplier’s skills and risks aversion. The knowledge-based model for offer definition, offer assessment and offer confidences is based on a constraint satisfaction problem.

Companies act today in a collaborative way, and have to master their product design and supervision processes to remain productive and reactive to the perpetual changes in the industrial context. To achieve this, authors propose a three-layers framework. In the first layer, the design process is modelled. In the second, the traces related to the decisional process are captured. In the third, both the collected traces and the design context model are used to support decision-making. In this paper, authors address the first two issues by proposing a meta-model that allows one to capture the process’ decisional knowledge. The proposal is presented and then illustrated in a case study.

An engineering design process consists of a sequence of creative, innovative and routine design tasks. Routine tasks address well-known procedures and add limited value to the technical improvement of a product, even if they may require a lot of work. In order to focus designers work on added value tasks, the present work aims at supporting a routine task with a Design Archetype (DA). A DA captures, stores and reuses the design knowledge with a tool embedded in a CAD software. The DA algorithms drive the designer in selecting the most effective design concept to deliver the project requirements and then embody the concept through configuring a CAD model. Finally, a case study on the definition of a DA tool for gear design demonstrates the effectiveness of the DA tool.

Digital design and manufacturing are critical drivers of competitiveness but only few companies and organizations have the capability to support digitalization across the whole Product Lifecycle. In several cases the information flow is discontinuous, the roles and the issues are not properly defined, the tools are heterogeneous and not integrated in the company organization. An approach that considers an appropriate data and information organization, an efficient internal organization and the availability of integrated software tools that are implementing the industrial best practices, could innovate important and critical aspect of the industrial processes. This paper gives an overview of the main themes related to Knowledge Management in industrial context, focusing on product configuration process. The current role of the knowledge in product configuration will be discussed. Then, a brief overview on Knowledge-based Engineering will be presented. Regarding Knowledge Based methodology, acquisition and formalization techniques and tools will be analyzed. Finally, an application focused on assembly lines configuration will be presented.

The aim of “integrated prevention” is to conduct a preliminary risk analysis in order to achieve a lower level of risk in the design of future work equipment. Despite the many safety documents that exist, many companies, particularly SME/SMIs, do not yet apply these safe design principles. Integration of safety in the design process is mainly based on the individual knowledge or experience of the designers and is not conducted in any formalized way. In order to answer to this problem, this paper presents a methodology to involve engaging stakeholders in dynamic dialogue and a framework so that they may together define the information necessary for implementing safe design principles during the functional specification. The proposed methodology has been validated to industrial case.

This paper discusses the need to identify the rule that can be used as a unified point of references to styling DNA in automotive design. Recently, there is no promising model or framework that can be used in design methodology for styling DNA. In reference to that, inquiry research activity was carried out among selected Malaysian public and styling designers in PROTON. Findings from the study indicated that the perception of designers positively correlate with preferences of Malaysian users. Furthermore, results showed that designers consistently tried to create a concept via sketches based on a specific area of the car. Consequently, the sequence maps or locus have been established in this research and the challenges revealed how it can be used as a starting point to build or create characters as embodied agents of character traits concerning brand and identity of a car design.

In order to improve product performance, this paper provides specific guidance for designers to take product usage information into account in the early design phase. Firstly, the influence of design modification on design process is presented. Secondly, by reviewing some helpful studies, the primary reasons of the design modification occur after prototyping phase is stated. Thirdly, we propose that a user manual can be created before prototyping stage to direct the design activities. We define the design process as 3 levels, function level, task level, and behavior level. At the function level, designers decompose the high-level function into sub-functions until elementary level that all elementary functions are arranged in a pre-determined order. At the task level, designers allocate each elementary function to machine, user, or interactive between the two. At the behavior level, Designers study the interrelationships between user’s behavior and structure’s behavior to examine whether the interactions meet the required performance or not. Finally, the simple case verifies the effectiveness and practicability of the proposed method in this paper.

Ergonomic design of automotive seat is a very challenging task whose results may directly influence driver’s comfort and safety. Seat comfort can be improved by identifying car-packaging solutions that allow an optimal driver’s posture. In order to reduce the time and cost for testing, ergonomic analysis is carried out in virtual reality (VR) environment with digital human models (DHM) that can be used to simulate the anthropometric variability of a target population of users and thus verify the robustness of design solutions with respect to the anthropometrical noise factor. In this paper we illustrate a case study concerning the comfort improvement of a minicar packaging set up via robust ergonomic design (RED) with digital human models. The aim is the identification of the optimum levels for the seat control parameters that minimize the driver’s comfort loss with respect to a preferred posture. The approach adopted for the analysis of data obtained from the virtual experiments is based on the joint generalized linear modeling of mean and dispersion of the driver’s postural comfort loss (i.e. the ergonomic response of interest).

Analysis of human-related aspects is fundamental to guarantee workers’ wellbeing, which directly limits errors and risks during task execution, increases productivity, and reduces cost [1]. In this context, virtual prototypes and Digital Human Models (DHMs) can be used to simulate and optimize human performances in advance, before the creation of the real machine, plant or facility. The research defines a human-centred methodology and advanced Virtual Reality (VR) technologies to support the design of ergonomic workstations. The methodology considers both physical and cognitive ergonomics and defines a proper set of metrics to assess human factors. The advanced virtual immersive environment creates highly realistic and interactive simulations where human performance can be anticipated and assessed from the early design stages. Experimentation is carried out on an industrial case study in pipe industry.

The application of ergonomic principles to the design of processes, workplaces and organizations is not only a way to respond to legal requirements but also an indispensable premise for any company seeking to pursue a business logic. This paper shows a cheap and effective method to perform the ergonomic analysis of worker postures in order to optimize productivity and obtain the highest ergonomic ratings. Evaluations were performed for the 5°, 50° and 95° percentiles according to OCRA and NIOSH methods of biomechanical risk assessment. The results highlighted the need for improvements. A virtual simulation using DELMIA® software and the use of workers’ checklists drew attention to problems causing significant physical stress, as identified by ergonomic tools. An ergonomic/comfort-driven redesign of the work cell was carried out, and CaMAN® software was used to conduct a final comfort-based analysis of the worst workstation in the work cell.

This work describes a simple, fast, and robust method for identifying, checking and managing the overlapping image keypoints for 3D reconstruction of large objects with numerous geometric singularities and multiple features at different lighting levels. In particular a precision 3D reconstruction of an extensive architecture captured by aerial digital photogrammetry using Unmanned Aerial Vehicles (UAV) is developed. The method was experimentally applied to survey and reconstruct the ‘Saraceni’ Bridge’ at Adrano (Sicily), a valuable example of Roman architecture in brick of historical/cultural interest. The variety of features and different lighting levels required robust self-correlation techniques which would recognise features sometimes even smaller than a pixel in the digital images so as to automatically identify the keypoints necessary for image overlapping and 3D reconstruction. Feature Based Matching (FBM) was used for the low lighting areas like the intrados and the inner arch surfaces, and Area Based Matching (ABM) was used in conjunction to capture the sides and upper surfaces of the bridge. Applying SIFT (Scale Invariant Feature Transform) algorithm during capture helped find distinct features invariant to position, scale and rotation as well as robust for the affinity transformations (changes in scale, rotation, size and position) and lighting variations which are particularly effective in image overlapping. Errors were compared with surveys by total station theodolites, GPS and laser systems. The method can facilitate reconstruction of the most difficult to access parts like the arch intrados and the bridge cavities with high correlation indices.

This paper describes a methodology for carrying out an accurate mechanical characterization of an amorphous hyperelastic rubber-like material (carbon black filled natural rubber) by a custom-made experimental setup for bulge testing. Generally, during sample testing the slight anisotropy of the internal polymer structures, primarily due to the calendering process is neglected. This methodology is able to evaluate these effects. A hydraulic circuit inflates a thin disk of rubber blocked between two clamping flanges with adjustable flow rate, thus controlling the speed of deformation of the sample. The device has a sliding crossbar, which moves proportionally as the membrane inflates. A stereoscopic technique is able to capture with pixel precision and identify the strain on a silk-screen grid printed on the upper surface of the sample. For each acquisition step, the epipolar geometry of the image pairs is represented in a single absolute reference system integral to the experimental setup. The acquired images are processed using geometrical algorithms and different filters. In this way an extremely precise 3D reconstruction of the sample is created during the bulge test. Slight anisotropic behaviors due to the rubber calendering process have been observed and measured since the first steps of the bulge test, where the strains are minimal and principal strain direction in equibiaxial tension test are determined.

Definition of size, shape and location of defects into a mechanical component is of extreme importance in the manufacturing industry in general and particularly in high-tech applications, and in applications that can become dangerous due to the structural failure of mechanical components. In this paper, a laser-UT system has been used to define position and shape of internal defects in aluminum plates. An infrared pulsed laser is used to generate ultrasonic waves in a point of the plate and a CW laser interferometer is used as receiver to acquire the out-of-plane displacements due to the ultrasonic waves in another point of the plate. The method consists of acquiring a B-Scan map on which some information on the defects in the mechanical component are visible. Storing the characteristics of the wave reflected by the defect and acquired in the B-Scan, the detection and the drawing of the defect is possible. The acquisition of the times of arrival of the waves reflected by the defect from the B-scan allows defining large parts of the shape of the defect. The times of arrival are acquired from the B-scan by analyzing the colour variations due to the wave reflected by the defect. The experiments operated from both sides of the plate allow drawing the defect in a virtual image of the plate section, from which the definition of defect shape and position can be determined.