Advances in Material Science and Engineering

Table of Contents

1. Frontmatter

2. Tig Welding of Dissimilar Steel: A Review

   N. Echezona, S. A. Akinlabi, T. C. Jen, O. S. Fatoba, S. Hassan, E. T. Akinlabi

   Abstract

   Dissimilar welding of metals has gained lots of interest from researchers worldwide due to its numerous benefits. The fact that dissimilar weld joints are projected to give more versatility in the production and design of industrial and commercial components cannot be disputed. This paper presents a review of the recent works done on TIG welding of dissimilar steel with the focus on properties, structure, and performance relationships. It also includes the influence of welding parameters on the quality of joints. The papers for investigation in this work were considered from 2012 to date. A total of 29 research papers were chosen for our consideration after an in-depth examination of several such papers. There is a growing need for dissimilar welding of steel due to its various benefits such as the production of lightweight machine parts, production of less expensive engineering components with acceptable corrosion resistance, high strength, and recyclability in the power generation, chemical, petrochemical, and automotive industries. Welding of dissimilar steels is very challenging due to the dissimilarities in their chemical, physical, and metallurgical properties. Although other welding processes such as solid-state welding processes and some fusion welding techniques such as laser welding and electron beam welding have produced high-quality dissimilar steel joints, their application has been limited due to their high cost. Consequently, the TIG welding technique has been widely employed for welding of dissimilar materials because of its low cost, stability, and high quality of weld produced. In TIG welding, process parameters such as the current, gas flow rate, voltage, welding speed play a vital role in the standard of the weld produced. Several types of research have proved successful TIG welding of dissimilar steel with reliable joint performance as illustrated in this study. The review concluded that TIG welding of dissimilar steel is capable of producing joints with acceptable properties in the production and manufacturing industry.

3. Development of a Parabolic Trough Solar Water Heater for Domestic Houses in Ongwediva

   Sam Shaanika, Mutiu Erinosho, Fillemon Nangolo, Ester Angula

   Abstract

   In this paper, the existing solar water heating systems were studied with their applications in order to find better design approaches. Solar energy is free, environmentally clean, and therefore it is accepted as one of the most promising alternative energy sources. Nowadays, plenty of hot water is used for domestic, commercial and industrial purposes. Various resources such as coal, diesel and gas are used to heat water and sometimes for steam production. Solar energy is the main alternative to replace the conventional energy sources. Namibia have enough solar energy that can be captured and used in domestic water heating and rural areas. A design of a “Parabolic Trough Solar Water Heater” (PTSWH) that incorporates a solar tracker was designed since it is a better system that can concentrate solar energy on water pipes compared to the flat solar water heater. The size of the system depends on the availability of solar radiation, the temperature requirement of customers, the geographical condition and the arrangement of the solar system. The PTSWH system was designed using the above parameters.

4. Design of Specimen Table for Laser Deposition Operation

   Mutiu Erinosho, Ester Angula, Fillemon Nangolo, Sam Shaanika

   Abstract

   The KUKA robotic arm is used for laser cladding, repair and maintenance of parts or engine components. The KUKA robot sprays metal powders on the testing substrate or component to be repaired or cladded and solidified after melting. However, during this process, not all metallic powders is utilized and as such, some were wasted. About 40% approximately are wasted for a given operation. Due to the wastage and cost of these powders, four tables were developed to recover the wasted powders, but only one was selected due to the convenience and ease of powder retrieval. The selected concept which is Concave Hollow Table was put through a stress analysis with MSST and MDET failure criteria and the maximum displacement analysis obtained was 1.91902 mm on a high load of 200 kg that was used.

5. Design of a Stacking System for a Small-Scale Warehouse

   Mutiu Erinosho, Fillemon Nangolo, Ester Angula, Ignatius Shahonya

   Abstract

   Material handling system is the art and science of conveying, elevating, positioning, transporting, packaging and storing of materials. It’s not today that stacking rack systems have been in use in the warehouses. However, in some warehouses, the stacking racks available needs the use of forklift for the retrieval of goods. This paper is focused on the design of a mini warehouse stacking system that allows the retrieval of goods and equipped with features that allows easy flow of material from the loading end and without the use of forklift with the aisles. A 3D CAD model was developed and analysis was carried out and the results showed that material could easily and efficiently be moved from the loading end to the receiving end and be retrieved with the help of a lifting mechanism with ease. This design will improve the safety of the workers, goods and the efficiency of the general warehouse.

6. The Prospective Direction of Solar Energy in Namibia

   Mutiu Erinosho, Ester Angula, Fillemon Nangolo, Sam Shaanika

   Abstract

   The fluctuating output of the hydropower station, which is the main generating plant of the country due to drought, the ageing of coal fired power station, and the increase in demand of electricity have caused a gap between the energy demand and supply. To mitigate the problem, inexhaustible and sustainable energy sources should be implemented. Thus, solar energy, due to its abundance in nature is one the ways chosen to meet the demand and fill this gap. This study examines the internal strengths and weaknesses, and external opportunities and threats to expand domestic solar technologies usage. Hence, the strengths in terms of solar potential, low population density of the country, the dependence on biomass, the government support were explored whereas the high upfront cost of solar technologies, expensive off-grid solar off-grid plants, and the lack of human capital were found to be the weaknesses that need to be addressed and fixed. Suggestions were further revealed on the ways to enhance solar technologies based on the strengths discussed.

7. Development of a Refrigeration System Test Rig

   Ester Angula, Fillemon Nangolo, Mutiu Erinosho, Sam Shaanika

   Abstract

   Thermodynamics is an important aspect of mechanical engineering, and the fundamental part of it is refrigeration. It is often beneficial for students of mechanical engineering to observe practically at the working principle of a refrigeration system. Thus, this paper presents the development of a vapour compression refrigeration system test rig to be used for student’s practical work in the mechanical engineering laboratory at engineering campus, University of Namibia. The refrigeration system was designed to have a refrigeration capacity of 25 kW and to provide cooling at a desired temperature of 16 °C. The calculations for the refrigeration system were based on a thermodynamic analysis of the components, which makes use of the principles of conservation of energy. The system’s theoretical Coefficient of Performance (COP) was found to be 9.19. A 3D CAD model of the test rig was developed and the layout of the test rig was kept simple with all components clearly identified.

8. Scaling and Fouling of Reverse Osmosis (RO) Membrane: Technical Review

   Ignatius Shahonya, Fillemon Nangolo, Mutiu Erinosho, Ester Angula

   Abstract

   An estimated 1.2 billion inhabitants are still faced with the water crises worldwide and the number keeps increasing. The population growth, rising standards of living, industrial proliferation, water source contamination and climate change remains one of the contributing factors to water scarcity. The use of reverse osmosis technology to desalinate brackish and sea water is one of the key reliable sources of alternatives water supply. However, the technology is subjected to scaling and fouling challenges. Fouling and scaling are regarded as major cost intensive trials in the RO desalination industry. Scaling is mostly stirred by the precipitation of calcium carbonates, calcium sulphates, barium sulphate and silicates on the RO membranes which clogs the membrane pores whereas, fouling is by the deposition of suspended matters, colloids and micro-organisms on the membrane. Even though there are several methodologies developed to control scaling and fouling, the feed water composition, pre-treatment, temperature, chemical composition and filtration process prior to RO membrane filtration remains different from plant to plant, making it almost impossible to predict, mitigate or control fouling and scaling.

9. Design of a Fan Motor Lifting Mechanism for an Air-Cooled Condenser

   Ester Angula, Fillemon Nangolo, Mutiu Erinosho, Jean Habiyaremye

   Abstract

   The Van Eck power plant is generating electricity based on the Rankine cycle in which the steam expanded in the turbine is condensed back to liquid. During this process, the plant uses the forced convection type of air-cooled condensers where the axil fans are used to maintain the air flow at a certain rated speed. The axil fan’s motors and gearboxes sometimes experience mechanical and electrical failures, thus has to be replaced or repaired. However, there are challenges of delivering the motors and gearboxes as well as safely conveying them into the condenser house. Currently, there is no proper mechanism to deliver the motors and gearboxes into the condenser house. Therefore, during motors and gearboxes repair or replacement, more time is spent, and maintenance workers are vulnerable to risks of injuries, while the equipment is vulnerable to damages. To solve these problems, several concepts were generated from which the most effective and reliable concept was selected. The manual stress analysis was conducted on the selected concept in order to determine the required sectional properties. Then, the CAD model was developed in Solidworks, and simulated to analyze the stress distribution on the model, thus verifying the manual stress analysis calculations conducted in order to ensure that the design is capable to lift the intended load safely.

10. Technical Review on Severe Plastic Deformation of Aluminium Series

    Mutiu Erinosho, Ester Angula, Fillemon Nangolo, Bolanle Ikotun, Oluwagbenga Johnson

    Abstract

    Severe plastic deformation (SPD) of Aluminium alloys has been of great interest to many researchers due to the improved properties that the alloy has exhibited from grain refinement up to micro and nanoscale structure. In this review, various processes of deformation have been presented such as high-pressure torsion, equal channel angular pressing, planar twist extrusion process, tube channel pressing and other deformation means. The research results from the application of various techniques of severe plastic deformation on different types of Aluminium alloys are presented in this review. This includes the final microstructural analyses after deformation, grain sizes, strength improvement, and electrical conductivity and other mechanical properties.

11. Microstructural and Mechanical Properties of Friction Stir Welding of AZ91D

    O. Kayode, E. T. Akinlabi

    Abstract

    In this study, a relatively new manufacturing process - friction stir welding (FSW) was used to join 3 mm thick AZ91D plates. The process was conducted at a traverse speed of 50 mm/min and rotational speed of 1000 rpm; and the weld sample’s microstructural and mechanical properties were evaluated. The microstructural analysis was conducted with an optical microscope. The mechanical properties evaluation includes tensile and microhardness tests. The microstructural analysis shows a defect-free sound joint of the materials with absence of voids and wormholes. The tensile strength of the weld was enhanced significantly and a joint efficiency of 109% was achieved. However, there was no substantial effect on the ductility and hardness properties of the weld sample. In conclusion, the FSW process is an efficient and sustainable technique to join and enhance the tensile properties of similar AZ91D alloys.

12. Microstructural and Mechanical Properties of Friction Stir Welding of AA1050

    O. Kayode, E. T. Akinlabi

    Abstract

    In this study, a sustainable manufacturing process – friction stir welding (FSW) was used to join 3 mm thick AA1050 plates in butt joint configuration. The process was conducted at a traverse speed of 50 mm/min and rotational speed of 800 rpm. The weld sample’s microstructural and mechanical properties were evaluated. The microstructural analysis was conducted with an optical microscope. The mechanical properties investigation includes tensile and microhardness tests. The microstructural analysis show a defect-free sound joint of the materials with absence of kissing bond. The mechanical evaluations revealed that the hardness property of the weld sample was not significantly affected by the welding process, but the tensile properties were slightly reduced. However, an acceptable joint efficiency of 94% was obtained, showing that FSW is a suitable sustainable welding process for joining of similar AA1050 alloys.

13. Total Productive Maintenance in Small and Medium-Sized Enterprises

    Literature Review T. X. Zhang, J. F. Chin

    Abstract

    The purpose of the paper is to review literatures related to total productive maintenance (TPM) in small and medium-sized enterprises (SMEs). The first part of paper presents the research background to underline the importance for SMEs to integrate holistic maintenance strategies in their productions. The second part of the paper briefly covers the history of equipment maintenance, followed by systematic discussion of TPM, including the definition of TPM, the eight pillars, the objective of TPM, and the benefits of TPM. Next, the paper summarizes the influencing factors and analyzes case studies to seek research gaps in TPM. As findings, the paper revealed that the suitability of TPM in SMEs and the need in research to pay attention to the implementation method by fully considering the changing characteristics of SMEs.

14. Spark Plasma Sintering of Ceramic Matrix Composite of TiC: Microstructure, Densification, and Mechanical Properties: A Review

    Samson Dare Oguntuyi, Oluwagbenga Johnson, Mxolisi Brendon Shongwe

    Abstract

    The application of monolithic/un-doped/single-phase ceramics has been limited due to their difficulty in sintering and low fracture toughness. Ceramic matrix composites have gained predominant attention in the past decades in comparison to monolithic/un-doped/single phase ceramics, this is as a result of the high fracture toughness, good wear resistance, and high hardness that they (ceramic matrix composite) possess. Also, the use of sintering additives in collaboration with the application of modern consolidation viz spark plasma sintering (SPS) has gained high prominence to nullify these challenges faced by ceramics. Although, previous review has highlighted the use of diverse techniques (hot press, hot isostatic, pressureless sintering, and SPS) on the consolidation of ceramics and its composites. Amidst all these techniques, SPS has stood to be an effective powder metallurgy route for achieving good microstructure and excellent mechanical properties. This review takes a research on the effects of nitrides based sintering additives on the microstructure, densification, and mechanical properties of titanium carbides ceramic matrix by SPS. The review finally concludes on the potential research importance on the types of sintering additives inclusion that should be in further research processes for improvement in material properties of titanium carbides.

15. Thermal Performance Modelling of a Flat Bare Tube Bundle Under Deluging Cooling Conditions

    Ester Angula, Paul Chisale, Fillemon N. Nangolo

    Abstract

    This work focuses on developing and improving a one-dimensional analytical, thermal model to be employed in predicting and optimizing of the performance of a flat bare tube bundle, under deluging cooling condition, commonly found the literatures. The flat bare tube bundle to be incorporated into the second stage of an induced draft Hybrid (Dry/Wet) Dephlegmator (HDWD) for a Direct Air-Cooled Steam Condenser (ACSC). The developed model is validated theoretically and evaluated analytically by using three approaches, which are: Poppe, Merkel, and heat and mass transfer analogy. The present model was also validated against the models for flat bare tube bundles from the literatures. The geometric orientation of the tubes (flat and round ends sections) was taken into account when modelling was performed. For the flat section of the tube, the governing differential equations were conducted in Cartesian coordinates. The cylindrical coordinates were employed, to derive the governing differential equations, for round ends tube. Heat transfer rate obtained by Poppe method is found to be 2.8% and 9.2% higher than that of Merkel, and heat and mass transfer analogy methods, respectively. By comparing the present model to that of flat bare tube bundle in the literatures, the heat transfer rate and air-side pressure drop were found to be 11% and 88% higher, respectively for both methods. Furthermore, the heat transfer rate for the model of delugeable round bare tube bundle (DRBTB) was found to be higher than that of the present model at both smaller and larger tube pitch, while the air-side pressure drop for the model of DRBTB was found to be lower and higher than that of the present model at smaller and larger tube pitch, respectively.

16. Investigation of the Mechanical and Microstructural Properties of TIG Welded Ti6Al4V Alloy

    P. O. Omoniyi, R. M. Mahamood, N. Arthur, S. Pityana, S. A. Akinlabi, S. Hassan, Y. Okamoto, M. R. Maina, E. T. Akinlabi

    Abstract

    The joint integrity of 1 mm thick sheets of Ti6Al4V alloy welded autogenously using TIG welding was investigated in this article. The current and gas flow rate were varied and their effects on the mechanical properties and microstructure of the weld were analyzed. Results show that the microstructure within the weld zone consists of α’martensitic phase and are coarse, which results in higher microhardness within the weld zone compared to the base metal. The samples with a higher gas flow rate were observed to also improve the tensile strength, while samples with a lower gas flow rate resulted in tensile strength below that of the base metal.

17. Prediction of the Temperature Behaviour During Friction Stir Welding (FSW) Using Hyperworks®

    Bahman Meyghani, Mokhtar B. Awang, Reza Teimouri

    Abstract

    Fundamentally, heat is needed during friction stir welding (FSW) for joining materials together. This heat is usually produced by friction force and material deformation. Therefore, friction coefficient is a significant factor and in order to increase the efficiency and the quality of the simulated model, there is a need to explore it accurately. However, previous studies used constant values of the friction coefficient resulting in inaccuracy of the model. This paper proposes, a mathematical formulation for predicting temperature dependent values of the friction coefficient using coulomb friction and von Mises yield laws. Then, the friction coefficient values are used to simulate a finite element model. HyperMesh® and HyperView® solvers have been employed from Altair Hyperworks® to simulate the process. The results of the model showed that, the temperature at the shoulder surface is always higher than the pin area, thus the heat generated by shoulder is found to be higher around 60 ℃. Furthermore, higher temperature at the advancing side (around 30 ℃) was obtained. Finally, the model is verified to show the accuracy of the predicted friction coefficient values and the results of the finite element model.

18. Investigation on Hybrid Geometric Modelling Construction for Core and Cavity of Injection Mould via CAD System

    Noor Atikah Abdul Malek, Mohd Salman Abu Mansor

    Abstract

    The use of injection moulding process is becoming more popular recently due to its profitable returns in plastic manufacturing industry. Its flexibility in changing the product type have made injection-moulding process widely used. Time consuming and complexity in designing the injection mould has led to developing a hybrid geometric modelling construction that can be used in designing a mould with CAD system for injection moulding process. A system that consist of a combination of two representation schemes will produce a mould design from the product part model. The algorithm for the two representation schemes are integrated to produce a hybrid scheme that later can generate mould design without a complex way. This research aims to study the existing methods in creating the core and cavity for the mould by developing algorithm. At the end of this study, the developed algorithm able to detect the topology for the part model. It able to recognise the characteristic of the model and interpret it in form of topology data. Then, it can develop a design for pair of core and cavity for injection mould.