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15th International LS-DYNA Conference

Detroit, 2018

Material Models for Thermoplastics in LS-DYNA® from Deformation to Failure
P. Reithofer, A. Fertschej, B. Hirschmann, B. Jilka, M. Rollant, 4a engineering GmbH
In the last years the demands of the automotive industry have led to a strong interest for a more detailed description of the behavior of thermoplastic materials and thus for more complex material cards including damage and failure. Also, the importance of gaining material data quickly has risen. Currently material and failure modeling in crash simulations typically deal with simple von Mises visco-plasticity (*MAT_024) and equivalent strain ...
Maximizing LS-DYNA® Performance and Scalability with In-Network Computing Acceleration Engines
Ophir Maor, Gerardo Cisneros, David Cho, Yong Qin, Gilad Shainer, HPC Advisory Council
The Co-Design Collaboration is a collaborative effort among industry leaders, academia and manufacturers, whose mission is to reach the next level of application performance by exploiting system efficiency and optimizing performance. The above is achieved through creating a synergy between the hardware and the software. One of the major outcomes of this collaboration is In-Network Computing technology. This technology enables data algorithms, ...
Mesh Sensitivity of Blast Wave Propagation
David A. Powell, David Bogosian, Baker Engineering and Risk Consultants;
Len Schwer, Schwer Engineering & Consulting Services
Calculation of blast propagation in air from a high explosive detonation is an often-used feature of LS-DYNA®’s Eulerian capabilities. To obtain credible results, a suitably fine mesh is needed, particularly in the vicinity of the explosive, to represent the nearly instantaneous rise of shock pressure and its gradual decay. In this paper, we aim to present a set of generally applicable guidelines for mesh refinement, using both 2-D axisymmetric ...
Meso-scale Modeling of Carbon Fiber Composites for Crash Simulation
Dennis Lam, Omar Faruque, James Cheng, Saeed Barbat, Guowei Zhou, Xuming Su, Alex Akkerman, Steve Schaller,
Ford Motor Company, Research and Innovation Center, Dearborn, Michigan
Typical compression molded laminated carbon fiber composites are made of stacked UD, woven and/or braided carbon fiber pre-pregs oriented differently through the thickness. Resulting micro-structure (layering, anisotropy, inhomogeneity, etc.) is quite complex and greatly affects their mechanical responses. In particular, crash characteristics of CF composites are quite complex and are dominated by both intra-laminar and inter-laminar failure ...
MLS-based SPH in LS-DYNA® for Increased Accuracy and Tensile Stability
Edouard Yreux, Livermore Software Technology Corporation
Two important limitations of the Smoothed Particle Hydrodynamics are low accuracy and tensile instability. While the former can be somewhat alleviated by employing very fine discretizations and renormalized formulations, the latter can only be slightly mitigated with heavy use of artificial viscosity. In addition, renormalized formulations can be unsuitable for extreme deformations and impact simulations, and excessive artificial viscosity can ...
Model Set up, Analysis and Results of the Inverse Forming Tool in ANSA
Evlalia Iordanidou, Georgios Mokios, BETA CAE Systems SA
With an ongoing aim to reduce the time a model requires to be prepared, the sheet metal forming studies have evolved to catch up. This affects initially the die designers, who are requested to decide the manufacturing processes early in the design process as well as process engineers who aim to incorporate stamping results in further studies. Feasibility analyses are one kind of such studies, performed to check whether a part can be created ...
Modeling and Simulation of PCB Cover Plate for Large Open Joints
Sagheer A. Ranjha, Robert W. Bielenberg, Ronald Faller, Scott Rosenbaugh, John D. Reid, Cody Stolle, Midwest Roadside Safety Facility Mechanical and Materials Engineering University of Nebraska-Lincoln
An improved LS-DYNA® model of steel cover plate for accommodating variable gaps in roadside portable concrete barrier (PCB) installations has been developed. A two-piece cover plate model was evaluated using non-linear finite element analysis program LS-DYNA. Baseline model of F-shape PCB validated with full-scale crash testing is presented. Baseline modeling and simulation details are discussed, including the range of numerical problems and ...
Modeling Bolts in LS-DYNA© Using Explicit and Implicit Time Integration
Nils Karajan, Alexander Gromer, DYNAmore Corporation;
Thomas Borrvall, DYNAmore Nordic;
Kishore Pydimarry, Honda R&D Americas, Inc.
When setting up models for analysis using the explicit solver in LS-DYNA, the method of how to model bolted connections is usually well known. However, when this model or even just certain substructures of the model are used for load cases to be solved using the implicit solver in LS-DYNA, problems might arise that you might have not been aware of before. Typical automotive load cases for LS-DYNA implicit involve roof crush, door sag, misuse and ...
Modeling of a Cross-Ply Thermoplastic for Thermoforming of Composite Sheets in LS-DYNA®
Kari D. White, James A. Sherwood, Department of Mechanical Engineering, University of Massachusetts Lowell One University Ave., Lowell, MA 01854, USA
Thermoforming is a very attractive process for the cost-effective high-volume production of high-performance composite parts. The process starts with an open-punch tool to produce a set of preforms. The preforms are then consolidated into a part using matched-tooling high-pressure compression molding. However, this process is prone to the formation of defects such as wrinkling of the plies as they conform to the compound-curvature geometries of ...
Modeling of Carbon-Fiber-Reinforced Polymer (CFRP) Composites in LS-DYNA® with Optimization of Material and Failure Parameters in LS-OPT®
Sheng Dong, The Ohio State University;
Allen Sheldon, Honda R&D Americas, Inc;
Kelly Carney, George Mason University
Carbon-fiber-reinforced polymer (CFRP) composite material has gained increasing popularity in aerospace, defense, automotive, and civil engineering. Its high strength-weight-ratio makes it efficient as a structural component. However, the structure of the layers of fibers oriented in different directions, together with the bonding matrix polymers, create challenges in crashworthiness modeling of CFRP parts as a standalone piece, not to mention ...
Modeling of Crazing in Rubber-toughened Polymers with LS-DYNA®
M. Helbig, A. Haufe, DYNAmore GmbH, Industriestrasse 2, 70569 Stuttgart, Germany
Rubber-toughened polymers such as acrylonitrile butadiene styrene (ABS) or high-impact polystyrene (HIPS) are composed of a thermoplastic matrix and small rubber particles, e.g. [1]. The enhanced fracture toughness and ductility, compared to the neat matrix material, are the advantages of rubber-toughened polymers [2]. These macroscopic effects are caused by mechanisms on the micro scale such as shear yielding, void growth and crazing. Crazing ...
Modeling the Axial Crush Response of CFRP Tubes using MAT054, MAT058 and MAT262 in LS-DYNA®
leksandr Cherniaev, John Montesano, Clifford Butcher, Department of Mechanical & Mechatronics Engineering, University of Waterloo, 200 University Ave. West, Waterloo N2L 3G1, Canada
Predictive capabilities of three LS-DYNA composite material models – MAT054, MAT058 and MAT262 – were investigated and compared with respect to modeling of axial crushing of CFRP energy absorbers. Results of crush simulations with non-calibrated material models were compared with available experimental data, and then parameter tuning was conducted to improve correlation with experiments. Furthermore, calibrated material models were used to ...
Modeling the Post-Peak Behavior for Crashworthiness Prediction of Composite Structures
Xinran Xiao and Danghe Shi, Composite Vehicle Research Center, Michigan State University
Composite structures exhibit superior specific energy absorption (SEA) than metallic structures. However, the application of composites in primary energy absorbing (EA) structures is still limited. The lack of reliable predictions for composite EA structures is considered to be one of the key factors. This paper discusses the importance of modeling the post-peak behavior in material models for crashworthiness prediction of composite EA ...
Multi-disciplinary Optimization using LS-DYNA®
Mr. Azhar rehmani A. Saiyed, MS, B.Eng., Wayne State University;
Dr. Bijan Khatib Shahidi, PhD, MBA, US Army, TARDEC;
Mr. Madan Vunnam, MS, PMP®, US Army, TARDEC
Crashworthiness, NVH (Noise Vibration & Harshness) are two distinct as well as very inter-connected attributes/disciplines of vehicle development process. As objectives of both are very differing, it is a challenge to design a vehicle equally performing in both with the global objectives of mass reduction and comfort. LS-OPT® is the tool, which can perform a multi-disciplinary optimization. Here we will perform a frontal crash of the vehicle ...
Multi-Layer Aluminum Formability Assessment Using Composite Shells in LS-DYNA® with the Linear Fracture Line Approach
Dr. Richard Burrows, Novelis Global RD&T Center, Kennesaw GA, USA
Multi-layer aluminum sheet offers exciting design possibilities for automotive applications due to the outer layer having a ductility that suppresses fracture in drawing processes involving a high degree of bending. Formability assessment of multi-layer aluminum products such as AF200 thus offer a challenge to traditional techniques used in the industry such as Forming Limit Diagrams, owing to this large resistance to bending dominated fracture. ...
Multi-scale Material Modeling Applied from Specimen to Full Car Level using LS-DYNA®
Sylvain Calmels, e-Xstream Engineering
Tomorrow’s vehicles architectures will involve an increasing number of materials. Within this worldwide shared status, fiber reinforced materials are finding their way into not only aesthetic components but also semi-structural and structural components. Today, the question of how to accurately model such parts is not a topic of discussion anymore. All solutions dedicated to these materials proposed on the CAE market are based on multi-scale ...
Multi-scale Validation of a Butyl Rubber Neck Model for an Anthropomorphic Testing Device Designed for Underbody Blast
Alexander M Baker, Jeremy M Schap, F. Scott Gayzik, Wake Forest School of Medicine, Dept of Biomedical Engineering, Center for Injury Biomechanics;
Nicholas A Vavalle, Robert S Arminger2, Mark M Angelos, Johns Hopkins Applied Physics Laboratory;
Randolph S Coates, WIAMan Engineering Office, U.S. Army Research Lab
Underbody blast is a significant injury risk for the modern warfighter, and a well-validated human surrogate for underbody loading environments can assist in preventing or mitigating injury. We present a selection methodology and hierarchical validation of the neck material model for the Warrior Injury Assessment Manikin (WIAMan) LS-DYNA® model focusing on accuracy, consistency, and robustness. All simulations were run with LS-DYNA R 8.0.0
Multiscale Model Analysis of the Effects of Martensite Morphology and Martensite Volume Fraction on the Mechanical Property of Dual-Phase (DP) Steels: Parametric Study
Tarek Belgasam, PhD, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99163 (USA) Mechanical Engineering Department, Faculty of Engineering, University of Benghazi, Benghazi, Libya
Multiscale material modeling is important for directing the material design of heterogeneous materials with concurrent improvements in mechanical properties. In this study, the plastic deformation of DP steels with different microstructures features namely martensite aspect ratio, and martensite volume fraction was investigated. A new methodology that studies the effects and interactions of martensite aspect ratio (equiaxed versus elongated) and ...
Multiscale Simulations of Material with Heterogeneous Structures Based on Representative Volume Element Techniques
Zeliang Liu1, C. T Wu1, Bo Ren1, Roger Grimes, Livermore Software Technology Corporation, Livermore, CA 94551
Wing Kam Liu, Northwestern University, Evanston, IL 60208
This paper presents a concurrent multiscale simulation framework for materials with heterogeneous structures (e.g. composite). This avoids the burdens of finding the macroscale phenomenological models and tedious calibration processes by directly establishing the connection between the microstructure and macro-response through computational homogenization. In the homogenization process, the model links every macroscopic integration point to a ...
Numerical Investigation of a Glider Seat Cushion Under Shock Loading Using LS-DYNA®
Devon Downes, Manouchehr Nejad Ensan, Eric Chen, Andrew Price, SilinYang, National Research Council Canada
The objective of this study was to numerically simulate the shock mitigation capability of a glider seat cushion structure, at attenuating impact loading on the human pelvis. The cushion structure was comprised of two dissimilar 1” foam layers, T-41 and HS-70 foam, each colloquially known as Temper foam and Ethafoam, respectively. The Low Density Foam (Mat_57) constitutive material model was used to model the behavior of each cushion layer. The ...
Numerical Ricochet Model of a 7.62 mm Projectile Penetrating an Armor Steel Plate
Marvin Becker, Marina Seidl, Jean-François Legendre, French-German Research Institute of Saint-Louis;
Miriam Mehl, University of Stuttgart (Institute for Parallel and Distributed Systems);
M’hamed Souli, University of Lille (Mechanical Department)
Armored vehicles are designed to favor projectile ricochet and thus avoid perforation while providing a certain surface obliquity for the most probable threat direction. In the latest development not only new materials but also new design approaches are investigated using computer simulations. These simulations allow us to study quantitative dependencies of certain parameters which are difficult to determine experimentally, e.g. the influence of ...
Numerical Simulation of Aircraft Seat Compliance Test using LS-DYNA® Implicit Solver
Satish Pathy, LSTC, Livermore, CA;
Thomas Borrvall, DYNAmore Nordic AB, Linköping, Sweden
With the possibility of using numerical simulation results in place of dynamic tests for aircraft seat compliance, use of LS-DYNA for this purpose is gaining traction and visibility. This test is done in two parts – In the first part which is quasi-static, the seat undergoes “roll” and “pitch” at the attachment mounts, which preloads the seat structure, and, in the second part an acceleration pulse of 16g’s is applied to the seat system and ...
Numerical Simulation Transcatheter Aortic Valve Implantation and Mechanics of Valve Function
M.S. Hamid, Ph.D., Advanced Computational Systems LLC, Rochester, MI 48306
As the older population increases, age-related diseases such as aortic stenosis is a common heart condition in which there is a thickening and calcium deposition in the aortic root and aortic valve leaflets. This results in a host of symptoms like angina, embolism, stroke and sudden death. Current default treatment for severe aortic stenosis is surgical aortic valve replacement. Mechanical and bioprosthetic heart valves are common choice for ...
Numerical Simulations of Vehicle Restraint Systems
M. Šebík, M. Popovič, SVS FEM s.r.o., Czech Republic
This paper provides an overview of the progress that has been achieved so far in the investigation of restraint abilities of portable road barriers with integrated anti-noise wall. The aim of this project is to develop finite element models that would be able to faithfully describe actual crash tests of several categories. Numerical simulations using these models could significantly reduce financial and time costs connected with the development ...
Occupant Injury Criteria, a Complete Solution for the Evaluation of Occupant and Structural, Simulation and Physical Test Results in META
Claes Ljungqvist, Jacob Wass, Nikos Tzolas, Peter Appelgren, Volvo Car Corporation, Volvo Car Corporation, BETA CAE Systems SA, BETA CAE Nordic AB
For any type of simulation and after each solver run, the vast majority of the post processing actions for the evaluation of results and report generation are always the same. Particularly for Occupant Safety tests the increasing number of regulations, the use of different dummy types per regulation-test as well as the different vehicle variants that may exist and have to be tested, significantly increase the number of simulations and ...
Occupant Response in Rollover Crashworthiness Assessment of Cutaway Bus
MohammadReza Seyedi, Grzegorz Dolzyk, Sungmoon Jung, Jerzy Wekezer,
FAMU-FSU College of Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046
The objective of this study is to assess the injury risk and rollover mechanism of cutaway bus during two rollover crash tests using finite element method. Based on two well-established test procedures, ECE-R66 and SAEJ2114, different rollover scenarios were conducted. The full finite element (FE) model of cutaway bus which was verified by pervious studies, and Hybrid III 50th male Anthropomorphic Test Device (ATD) were deployed to conduct the ...
Optimisation of Fixturing Clamps to Improve Panel Measurement Robustness
Ben Crone, Arup;
Michael Buckley, aguar Land Rover;
Amelia Agnew, Arup
Tolerance measurement of sheet metal parts – such as those used in body in white assembly – is a critical task for the automotive industry that can lead to significant financial losses as a result of poor gauge R&R design and data misinterpretation. Current measurement systems use clamps to load panels onto fixtures. However, since non-rigid parts deflect with clamping pressure and under their own self-weight, measurement reproducibility and ...
Optimizing the Biofidelity of the Warrior Injury Assessment Manikin through Design of Experiments
M.P. Boyle, A.M. Lennon, N.A. Vavalle, M.T. Shanaman, C.W. Lomicka, C.O. Pyles, R.S. Armiger, The Johns Hopkins University Applied Physics Laboratory;
J.P. Schap, A.M. Baker, F.S. Gayzik, Wake Forest University Center for Injury Biomechanics;
M.R. Chowdhury, Army Research Laboratory, Adelphi
With improvised explosive devices beneath military vehicles causing an increasing number of casualties amongst warfighters, the United States Army requires a method by which to evaluate injury mitigation technologies in vehicles, including seat designs and other safety systems. In response to complications associated with the use of Post Mortem Human Subjects (PMHS), the United States Army Research Laboratory initiated an endeavor to develop a ...
Parametric and Convergence Studies of the Smoothed Particle Galerkin (SPG) Method in Semi-brittle and Ductile Material Failure Analyses
Youcai Wu, C.T. Wu, Wei Hu, Livermore Software Technology Corporation
This work presents the state-of-the-art status of the Smoothed Particle Galerkin (SPG) method [1, 2] in LS-DYNA®. The SPG method is a new generation meshfree method developed for modeling the semi-brittle and ductile material failure [3-5]. Different from the conventional finite element method (FEM) where the element erosion technique is utilized to mimic the material separation, the SPG method introduces a bond-based material failure ...
Performance Analysis of LS-DYNA® in Huawei HPC Environment
Pak Lui, Zhanxian Chen, Xiangxu Fu, Yaoguo Hu, Jingsong Huang, Huawei Technologies
LS-DYNA is a general-purpose finite element analysis application from LSTC. LS-DYNA is capable of simulating and solving complex real-world structural mechanics problems in an HPC cluster environment. In this paper, we are analyzing different areas that can impact on the performance of LS-DYNA by comparing different hardware components in Huawei HPC cluster environment. By evaluating the components, such as CPUs, network interconnects, system ...
Phase Change Equation of State for FSI Applications
Mhamed Souli, Ramzi Messahel, Lille University France;
Cyril Regan, Camille Ruiuc, Ingeliance Technologies, Agence de Bordeaux, France;
Bernard Cohen, Romain Ceyrolle, Sylvain Durel, EDF – Direction Production Ingénierie Marne la Vallée France
To simulate fast transient phenomena, one must consider realistic compressible fluid models that take into consideration phase change, shock wave generation and its propagation. In an industrial framework, such phenomena occur mostly near industrial apparatuses such as pumps, propellers, impellers and control valves. The rapid collapse of cavitation produces strong shock waves that may harm the interacting structure. In this paper, we present ...
Plasticity and Damage Modeling of the AA7075 Aluminium Alloy for Hot Stamping
G. D’Amours, National Research Council Canada, Aluminium Technology Centre, Saguenay, Canada;
A. Ilinich, Ford Research and Innovation Center, Dearborn, Michigan, USA
LS-DYNA® has several plane stress material models available for isothermal aluminum sheet stamping, most notably *MAT_3-PARAMETER_BARLAT, *MAT_BARLAT_YLD2000, and *MAT_KINEMATIC_HARDENING_BARLAT89. Recent models such as *MAT_BARLAT_YLD2000 based on Barlat’s YLD2000 yield surface accurately capture plastic flow and yield anisotropy of most aluminum sheet alloys. Some of these models are also applicable for non-isothermal forming. However, there ...
Preliminary Validation of a Detailed Finite Element Model of a 50th Percentile Male Pedestrian
Wansoo Pak, Costin D. Untaroiu, Virginia Tech, Blacksburg, VA, USA;
Berkan Guleyupoglu, Bharath Koya, Scott Gayzik, Berkan Guleyupoglu2, Bharath Koya2, Scott Gayzik
The pedestrian is one of the most vulnerable road users and comprised about 22% of the road crash-related fatalities in the world. While pedestrian protection regulations involving subsystem impact tests have been proposed, they cannot capture the whole vehicle-pedestrian interaction during car-to-pedestrian collisions (CPC). A few pedestrian finite element (FE) models representing 50th percentile male (M50) have been developed and validated ...
process2product simulation: Closing Incompatibilities in Constitutive Modeling and Spatial Discretization with envyo®
Christian Liebold, Dr. André Haufe, DYNAmore GmbH, Industriestrasse 2, D-70565 Stuttgart, GER
Within the automotive sector but also other industries, closing the simulation process chain from manufacturing towards the final crushing analysis becomes more and more important since it is well understood that the manufacturing process influences material properties such as initial damage, pre-stresses, induced plastic strains, differing thicknesses, or locally varying engineering constants. In LS-DYNA®, it is possible to consider such ...
Productivity and Quality of LS-DYNA® Analyses: Implementing a Tailor-made Software Solution for the Transport and Storage of Radioactive Materials
Gilles Marchaud, Valérie Saint-Jean, ORANO TN, Montigny-le-Bretonneux, France
For more than 50 years, ORANO TN (formerly AREVA TN) has been supplying customer-focused, innovative transportation and storage solutions for radioactive material with the highest levels of safety and security. Within a context of stringent regulations, ORANO TN performs LS-DYNA analyses to evaluate the crashworthiness of casks and to reduce the number of costly real tests. Continuous effort is being made to improve these analyses. Part of the ...
qd – Build your own LS-DYNA® Tools Quickly in Python
C. Diez, Lasso GmbH Germany
CAE is a large field with many different use cases. This high diversity yielded a large variety of tools, which help us engineers to achieve a high working performance every day. Unfortunately the situation arises, where engineers need to solve an additional, sometimes client or company-specific tasks, where no tool yet exists. Many of these tasks require usually only one key element: comfortable and fast data access.
Qualification of Launcher Tank Dynamic Behaviour through Vibratory Experiments using Discrete Element Spheres
Tess Legaud, Vincent Lapoujade, DynaS+;
Pierre-Louis Chiambaretto, Sinh Khoa Nguyen, Yves Gourinat, Université de Toulouse;
Valia Fascio, ATECA
Liquid hydrogen associated to liquid oxygen is one of the highest specific impulse propellant widely used for launchers propulsion. However, due to the fluid high explosiveness, full scale vibratory tests on tanks filled with liquid hydrogen is not advisable. The EASYNOV TANKYOU project, financed by the French Occitanie region aims at finding a safe substitute metamaterial that should be able to represent the liquid hydrogen vibratory ...
Randles Circuit Parameters Set Up for Battery Simulations in LS-DYNA®
Sarah Bateau-Meyer, Pierre L’Eplattenier, Livermore Software Technology Corporation, Livermore, CA;
Jie Deng, Min Zhu, Chulheung Bae, Theodore Miller, Ford Motor Company, Research and Innovation Center, Dearborn, MI
A multi physics model for battery abuse was recently introduced in LS-DYNA. This model predicts coupled mechanical, thermal, electrical and electro-chemical responses. The complex electro-chemical behavior is described by simple equivalent circuits, called “Randles” circuits. Each Randles circuit connects two vis-à-vis nodes of the positive and negative current collector layers and consists in a State-Of-Charge (SOC) dependent voltage source, an ...
Random Vibration Fatigue Life Simulation of Bolt-on Metal Brackets using LS-DYNA®
Jong S. Park, Ramakrishna Dospati, Ye-Chen Pan, General Motors;
Amit Nair, Livermore Software Technology Corporation
Prediction of Vibration Fatigue Life is an important milestone during product design and development of Vehicle Brackets. Bracket in Vehicle is defined as a simple structure fastened to foundation structure or other brackets supporting mass of various modules. CAE simulation for Fatigue Life prediction gives useful information early in design cycle, and saves considerable time and cost compared with physical Shaker Table tests. LS-DYNA Implicit ...
Rapid Simulations of Welding and AM using LS-DYNA® and LS-PrePost®
Mikael Schill, Anders Jernberg, Anders Bernhardsson, DYNAmore Nordic AB, Linköping, Sweden;
Simulation of the welding process in LS-DYNA has been continuously improving the recent years. The functionality in terms of solvers, materials, heat source and preprocessing GUI have been continuously expanded. One of the issues that remains to be solved is the sometimes quite long simulation times. The solution time of a welding simulation depends largely on the length and speed of the weld. This is especially true in Additive Manufacturing ...
Re-Using Crash Models for Static Load Cases with Minimal Effort
Anders Jonsson, DYNAmore Nordic AB
To demonstrate the implicit capabilities in LS-DYNA®, some examples of load cases typical for automotive applications are presented. A public FE-model of a mid-size passenger car (including interior, tires, suspension, exhaust system etc.) originally intended for explicit road-side safety analyses was, by minimal modifications, converted for implicit analyses. Some recommendations on how to go from an explicit (crash) model to an implicit model ...
Realistic Stochastic Virtual Microstructure Generation for Woven Fabrics and Textile Composites: The Thermal Growth Approach
Gaurav Nilakantan, Teledyne Scientific & Imaging, Thousand Oaks, CA 91360, USA
Generating realistic 3D yarn-level finite element models of textile weaves and impregnated textile composites poses a challenge because of the complexity of the 3D architecture and the need for achieving high quality finite elements and non-intersecting yarn volumes. A common approach is to sweep a constant yarn cross-sectional shape along a smooth and continuous centerline that repeats over a unit cell length. This approach breaks down with ...
Recent Developments in *DEFINE_PRESSURE_TUBE for Simulating Pressure Tube Sensors in Pedestrian Crash
Jesper Karlsson, DYNAmore Nordic
This paper presents recent developments of the new keyword *DEFINE_PRESSURE_TUBE, designed to efficiently simulate pressure waves in thin air-filled tubes. The primary application is a new crash detection system for pedestrian impact, where a thin air-filled tube is embedded in the front bumper and fitted with pressure sensors at the ends. On impact, the tube is compressed and a pressure wave travels to the sensors, enabling localization and ...
Recent Developments in Isogeometric Analysis for LS-DYNA®
David Benson, Attila Nagy, Liping Li, LSTC, Livermore, CA, USA;
Stefan Hartmann, Dynamore GmbH
Isogeometric analysis (IGA) uses the spline functions from CAD (computer-aided design) for analysis with the objectives of 1) reducing the effort of moving from design to analysis, 2) using the actual geometry of the parts from CAD instead of approximating them with polynomials, and 3) obtaining higher order accuracy through the higher order basis functions of CAD. LS-DYNA is the first commercial code to support IGA through the implementation of ...
Recent Developments in Isogeometric Analysis with Solid Elements in LS-DYNA®
Liping Li, David Benson, Attila Nagy, Livermore Software Technology Corporation, Livermore, CA, USA;
Mattia Montanari Nik Petrinic, Department of Engineering Science, University of Oxford Parks Road, OX1 3PJ
Oxford, UK;
Stefan Hartmann, Dynamore GmbH, Stuttgart, Germany
Isogeometric analysis (IGA), which uses the same geometry from CAD (computer-aided design) for numerical analysis, has been studied more and more in the past few years. The continuous development of IGA with shell and solid element has been added to LS-DYNA. Many of the standard analysis capabilities in LS-DYNA are now available for IGA such as explicit and implicit analysis. In this paper, we will provide updates on IGA: dynamics analysis using ...
Recent Developments in LS-DYNA® S-ALE
Hao Chen, Ian Do, Livermore Software Technology Corporation
The LS-DYNA ALE/FSI package is widely used in studying structures under blast loading. Generally, the ALE mesh is necessarily unstructured to accommodate complex geometries; however, for simple rectilinear geometries, a structured, logically regular, mesh can be utilized. Recognition of this latter case leads to algorithmic simplifications, memory reductions, and performance enhancements, which are impossible in unstructured mesh geometries.
Recent Improvements in LS-DYNA® Metal Forming Material Models
Jinglin Zheng, Xinhai Zhu, Livermore Software Technology Corporation
This paper solves two numerical issues arising from the return mapping scheme when simulating metal forming processes with LS-DYNA: (1) the returning mapping process fails to converge in cases where the effective plastic strain increment is small; (2) even when full convergence is accomplished at each time step, the global solution may diverge under small time step settings. For the first issue, a stable iterative scheme with global convergence ...
Recent Updates to the Structural Conjugate Heat Transfer Solver
Thomas Kloeppel, Peter Vogel, DYNAmore GmbH, Stuttgart, Germany
In this contribution recent developments in the structural conjugate heat transfer solver in LS-DYNA® are presented and discussed. The motivation for new implementations results from the specific needs in complex manufacturing processes such as for example hot forming, heat treatment and welding or multi-physics problems such as battery modelling. The paper first addresses two new options for the thermal contact. First of all, heat transfer ...
Robust FEM-BEM Coupling for LS-DYNA®'s EM module
Lars Kielhorn, Thomas Rüberg, Jürgen Zechner, TAILSIT GmbH
The electromagnetic (EM) solver module of LS-DYNA targets coupled mechanical/thermal/electromagnetic problems as they occur, for instance, in the simulation of metal forming, welding, and induction heating. The EM solver incorporates the coupling of Finite Element and Boundary Element Methods. The main advantage of this approach is that the volume discretization of the surrounding air region is avoided. This approach significantly reduces the ...
Safety Modeling of Lithium-ion Batteries under Mechanical Abuse
Jie Deng, Min Zhu, Chulheung Bae, Theodore Miller, Ford Motor Company, Research and Innovation Center, Dearborn, Michigan 48124;
Pierre L’Eplattenier, Sarah Bateau-Meyer, Livermore Software Technology Corporation, Livermore, California 94551
Lithium-ion batteries are one of the main energy storage devices in electrified vehicles. As their capacity and energy keep growing to meet the demand of longer driving range, their safety has become a primary concern due to their high energy and power density nature. Previously, abuse tests have been conducted to detect the failure conditions of lithium-ion batteries, but these tests can be expensive and time consuming. As such, computational ...