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2020 | Buch

Simulation Science

Second International Workshop, SimScience 2019, Clausthal-Zellerfeld, May 8-10, 2019, Revised Selected Papers

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Über dieses Buch

This book constitutes the refereed proceedings of the Second International Workshop on Simulation Science, held in Clausthal-Zellerfeld, in May 2019.
The 12 full papers were carefully reviewed and selected from 47 submissions. The papers are organized according to the following topics: optimization and distributed simulations; simulation of materials; self-organized and porous structures; simulation of materials: finite element and multiscale methods.

Inhaltsverzeichnis

Frontmatter

Optimization and Distributed Simulations

Frontmatter
Privacy-Preserving Human-Machine Co-existence on Smart Factory Shop Floors
Abstract
Smart factories are characterized by the presence of both human actors and Automated Guided Vehicles (AGVs) for the transport of materials. To avoid collisions between workers and AGVs, the latter must be aware of the workers’ location on the shop floor. Wearable devices like smart watches are a viable solution to determine and wirelessly transmit workers’ current location. However, when these locations are sent at regular intervals, workers’ locations and trajectories can be tracked, thus potentially reducing the acceptance of these devices by workers and staff councils. Deliberately obfuscating location information (spatial cloaking) is a widely applied solution to minimize the resulting location privacy implications. However, a number of configuration parameters need to be determined for the safe, yet privacy-preserving, operation of spatial cloaking. We comprehensively analyze the parameter space and derive suitable settings to make smart factories safe and cater to an adequate privacy protection workers.
Alexander Richter, Andreas Reinhardt, Delphine Reinhardt
Dynamic Management of Multi-level-simulation Workflows in the Cloud
Abstract
Executing dynamic simulations in a distributed environment allows saving resources and time which is a desired goal in research and industry. One example dynamic simulation is the multi-level-simulation. Here, specific parts of the simulation can be inspected on different levels of detail at runtime. To cope with the changing simulation requirements an elastic and scalable infrastructure is required, as well as an approach adjusting the infrastructure to the simulation needs. In this paper, we enhance a former approach coupling workflows with architectural needs to utilize monitored runtime information and support decision making. Moreover, we demonstrate the concept of executing dynamic simulations over a workflow based approach by dynamically choosing the levels of detail within a supply chain multi-level-simulation.
Johannes Erbel, Stefan Wittek, Jens Grabowski, Andreas Rausch
On Approximate Bayesian Computation Methods for Multiple Object Tracking
Abstract
In this article, we present further results on the use of Approximate Bayesian Computation (ABC) particle filters for multiple object tracking (MOT). Based on our previous work that uses the OSPA distance to select the k-nearest simulated measurements with respect to the actual measurements, we present and evaluate two further ABC variants. The first variant replaces the OSPA distance with a kernel distance, reducing the computational complexity significantly, while the second version exchanges our previous k-nearest-neighbour approach for a distance-based approach, commonly used in ABC algorithms. The algorithms are compared to conventional multiple object tracking algorithms in simulated scenarios with multiple objects.
Fabian Sigges, Marcus Baum
Investigating the Role of Pedestrian Groups in Shared Spaces through Simulation Modeling
Abstract
In shared space environments, urban space is shared among different types of road users, who frequently interact with each other to negotiate priority and coordinate their trajectories. Instead of traffic rules, interactions among them are conducted by informal rules like speed limitations and by social protocols e.g., courtesy behavior. Social groups (socially related road users who walk together) are an essential phenomenon in shared spaces and affect the safety and efficiency of such environments. To replicate group phenomena and systematically study their influence in shared spaces; realistic models of social groups and the integration of these models into shared space simulations are required. In this work, we focus on pedestrian groups and adopt an extended version of the social force model in conjunction with a game-theoretic model to simulate their movements. The novelty of our paper is in the modeling of interactions between social groups and vehicles. We validate our model by simulating scenarios involving interaction between social groups and also group-to-vehicle interaction.
Suhair Ahmed, Fatema T. Johora, Jörg P. Müller
ANNO: A Time Series Annotation Tool to Evaluate Event Detection Algorithms
Abstract
The research field of energy analytics is concerned with the collection and processing of data related to electrical power generation and consumption. Electricity consumption data can reveal information pertaining to the nature of underlying appliances, their mode of operation, and many other aspects. Sudden load changes, so-called events, constitute the principal source of information in such time series data, thus their reliable detection and interpretation is a prerequisite for accurate energy analytics. The development of event detection algorithms is, however, hampered due to the unavailability of comprehensive data sets that feature energy consumption time series with corresponding event annotations. We hence present ANNO, a tool to provide annotations to time series consumption data in a supervised fashion and use them for the development of energy analytics algorithms, in this work.
Jana Huchtkoetter, Andreas Reinhardt, Sakif Hossain

Simulation of Materials: Self-Organized and Porous Structures

Frontmatter
Vibration Frequency Spectrum of Water-Filled Porous Silica Investigated by Molecular Dynamics Simulation
Abstract
Using Molecular Dynamics (MD) method we evaluated the vibration characteristics of nanoporous silica material. The purpose of this work is to observe the effect of water filling inside the nanopores to the vibration property of silica-water compound system. The vibration frequency spectrum was obtained through the calculation of the velocity auto-correlation function during MD simulation execution. The interaction of atoms in the target was modeled using Reax Force Field. We varied the water density in the pore to observe the transition of the frequency spectrum as the effect of water molecule concentration. The result of our simulation demonstrates that water content in the nanopore modifies significantly the spectral profile of porous silica system. The deviation from pure silica vibration spectrum is a direct consequence from the interaction between silicate based material with the fluid.
Yudi Rosandi, Gheo R. Fauzi
Numerical Study of Dispersive Mass Transport in Homogeneous and Heterogeneous Porous Media
Abstract
A modular simulation approach is used to compute the flow of a fluid and the mass transport of tracers in the void space of computer-generated porous packings. Effective transport properties such as the diffusive tortuosity and the dispersion tensor are determined. First, we present and compare two different approaches to model mass transport in homogeneous porous media. Subsequently, heterogeneous porous media are considered, where we investigate the effect of walls on the structure of confined random sphere packings and how it affects the mass transport properties of a sphere packing. In addition, the hydraulic tortuosity is computed and its performance as a descriptor of porous media is compared with that of the diffusive tortuosity.
Hector Rusinque, Eugenia Barthelmie, Gunther Brenner
Generative Design Solutions for Free-Form Structures Based on Biomimicry
Abstract
Conventional engineering design approach is to solve a structure for its strength. On the other hand, natural shapes and structures are more free-form, using stiffness and flexibility whenever and wherever necessary. Form-finding approaches for structural design draws inspiration from different trades of nature. In this work, an attempt is made to generate free-form structures using biological forms like growth of a plant. Generative design strategy within constrained design space was developed, and behavior of such solutions under different loading are discussed. Thus a structure is evolved (and adapted) via bottom-up approach, and not constructed (and optimized) as top-down process.
Selected examples show the robustness and flexibility of the structures depending on the application. The testing examples also enable the designer to improve the problem statement along with the solution sets. A smooth back and forth parametric modeling process facilitates a smooth interaction between design and analysis, which is essential in form-finding approaches. A free-form self-organized shape would enable the algorithm to directly interact with printing techniques, easing manufacturing.
Gaurab Sundar Dutta, Leif Steuernagel, Dieter Meiners
Accelerating the Visualization of Gaps and Overlaps for Large and Dynamic Sphere Packings with Bounding Volume Hierarchies
Abstract
The Collective Rearrangement (CR) algorithm is widely used for simulating packings of spheres to gain insight into many properties of granular matter. The quality of a CR simulation can be judged with a visualization technique by directly visualizing the gaps and overlaps of the spheres with pixel precision in each iteration. This visualization technique is based on an Graphic Processing Unit (GPU) linked list, which requires that information for each pixel of each sphere to be stored in advance and then be sorted for each pixel independently. Such requirements impose restrictions on the scale of sphere packings that can be visualized. Instead, one can use ray tracing to resolve such problems. However, there is no available practical ray traversal algorithm for visualizing overlaps and gaps based on acceleration structures for ray tracing. This paper provides traversal algorithms based on Bounding Volume Hierarchies (BVH) to address this problem and can generally make the visualization process much faster than before and reduce the global memory requirement on the GPU to render larger scenes.
Feng Gu, Zhixing Yang, Michael Kolonko, Thorsten Grosch

Simulation of Materials: Finite Element and Multiscale Methods

Frontmatter
A Novel Approach to Multiscale MD/FE Simulations of Frictional Contacts
Abstract
In most applications, frictional contacts lead to a noticeable amount of wear, which influences the further frictional behavior. Thus, friction and wear have to be analyzed as a whole to gain powerful models. In such models the interactions of macroscopic and microscopic aspects have to be taken into account. Finite element (FE) simulations are the standard method to simulate macroscopic solid body mechanics. However, they are not suitable to represent microscopic behavior of bodies, especially abrasive friction depending on the roughness of the contact. In these applications, molecular dynamics (MD) simulations using explicit time integration schemes are a much better tool. The combination of both methods is an established approach for the solution of friction problems, which has been pursued by several authors. The usual way of linking both methods is to use MD domains for the boundary of contacting bodies modeled in FE instead of conventional contact elements. The interface between FE and MD domain is generally implemented by defining MD particles and FE nodes as coincident. With this approach, every time step of the MD simulation requires solving a linear equation system for the whole FE modeled solid. The computational cost of solving a sparse linear equation system is superlinearly dependent on its degrees of freedom. Furthermore, MD simulations use explicit time integration, which requires very small time steps to assure stability. Thus, it is disadvantageous to apply the current coupling method to large geometries, since large linear equation systems would have to be solved very often. In consequence, a different approach is required to apply multiscale MD/FE methods to complex geometries.
This paper introduces a novel approach to integrate multiscale capabilities into FE that allows solving large models at reasonable computational cost. The proposed approach integrates MD coupling into FE contact elements characterized by a nonlinear, history dependent friction law, which is trained with MD simulations. The roughness profile of sliding surfaces is modeled with elasto-plastic spherical caps serving as a mesoscopic level. The Hertzian contact between two spherical caps is handled at the microscopic level using an improved variant of the conventional node particle coincidence technique.
Henrik-Johannes Stromberg, Nina Gunkelmann, Armin Lohrengel
Numerical Investigation of Tri-Axial Braid Composite Structures as Crush Specimens Using the VPS-Solver
Abstract
This paper describes a new modelling approach for numerical investigations on the crushing behavior of tri-axial braid composite structures using the Virtual Performance Solution (VPS)-solver (also known as PamCrash; [1]) by way of its application to automotive related specimens.
In current VPS software, the crushing mechanism is modelled by a special crushing ply (PLY100), which is capable to model the mentioned mechanism phenomenologically but not able to behave as a splaying material which can possibly interact with other materials or itself [4]. With the presented novel approach, the visual structural behavior of a fiber reinforced plastic (FRP) sample and the shape of the corresponding load-displacement-curve can be simulated quiet accurately, especially for plane and oblique impactors. It is based on shell elements which are arranged in stacked order and implies a developed modelling strategy. In addition, a cohesive interface is defined to join the shell layers with each other. This interface acts as a matrix phase mixed with characteristics of braid yarns and contains a model for delamination. For experimental validation, a small extract was resorted of a large experimental study using a drop-weight-tower [8].
Sven Hennemann, Volker Hohm, Peter Horst, Lasse Twardy, Philip Zimmermann
Reinforcement the Seismic Interaction of Soil-Damaged Piles-Bridge by Using Micropiles
Abstract
This paper presents Three-dimensional numerical modeling of Soil-damaged Piles-Bridge interaction under seismic loading. This study focuses on the effect of developing plastic hinges in piles foundation on the seismic behavior of the system. In particular, this study is interested in evaluating the proposed approach for strengthening the system of soil-damaged piles-bridge. The proposed approach is based on using the micropiles whose significantly promoting the flexibility and the ductility of the system. This study was carried out using a Three-dimensional finite differences modeling program (FLAC 3D). The results confirmed the considerable effect of the developing of concrete plasticity in the pile’s foundation, which reflects in changing the distribution of internal forces between the piles, also, they show the efficiency of using the micropiles as a reinforcement system. The detailed analysis of the micropiles parameters shows a slight effect of pile-micropile spacing, while the use of inclined micropiles leads to attenuation of the internal forces induced in the piles and the micropiles themselves.
Mohanad Talal Alfach
Backmatter
Metadaten
Titel
Simulation Science
herausgegeben von
Nina Gunkelmann
Prof. Dr. Marcus Baum
Copyright-Jahr
2020
Electronic ISBN
978-3-030-45718-1
Print ISBN
978-3-030-45717-4
DOI
https://doi.org/10.1007/978-3-030-45718-1