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15th International LS-DYNA Conference

Detroit, 2018

*MAT_4A_MICROMEC – Theory and Application notes
P. Reithofer, A. Fertschej, B. Hirschmann, B. Jilka, 4a engineering GmbH;
A. Erhart, S. Hartmann, DYNAmore GmbH
Nowadays a great number of short and long fiber reinforced thermoplastics play a decisive role in the automotive industry to ensure affordable lightweight design and availability in large quantities. As seen in the last German LS-DYNA® Conference 2016, there is a strong industry interest to consider the manufacturing process induced local anisotropy in crash and general dynamic simulations.
A Comparison between two Methods of Head Impact Reconstruction
Arghavan Talebanpour, Lloyd Smith, School of mechanical and material engineering Washington State University
Reconstructing head impacts using computational models is an important tool in understanding brain injury mechanisms. Head impacts are often reconstructed by impacting an Anthropomorphic Test Device (ATD) with an object of interest. The head accelerations are measured and applied to a biofidelic finite element model. Little work has been done, however, to determine how the ATD accelerations applied to a numeric model approximate the brain ...
A Continuum Model of Deformation and Damage for API X70 Steel Based on the Theory of Strain Gradient
Mohammed Anazi, Hussein Zbib, Washington State University, School of Mechanical and Materials Engineering
This work shows the results of a continuum model of deformation and damage for API X70 steel based on the strain gradient theory. The model is developed according to the continuum mechanics of the elastic/viscoplastic framework. The constitutive equations of the model include the dislocation theory according to the roles of the statistically stored and geometrically necessary stored dislocation densities during plastic deformation. In addition, ...
A Customized Job Manager for Metal Forming Simulations with LS-DYNA®
Yuzhong Xiao, Xinhai Zhu, Li Zhang, Houfu Fan, Livermore Software Technology Corporation
In the metal forming analysis, the simulation time of each job is relatively short. However, due to the iterative modifications of the forming tools based on the simulation results, generally there would be several numerical tryouts. Also in addition to those with a single keyword file input, the number of simulation jobs consisting of several (e.g. the progressive die forming) or even dozens of sequential simulations (e.g. the iterative ...
A Non-linear Strain-rate Micro-mechanical Composite Material Model for Impact Problems
Ala Tabiei, Sandeep Medikonda, Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio 45221, USA
A micro-mechanical composite material model is developed to simulate the behavior of uni-directional composites under impact loading conditions in LS-DYNA®. The non-linear strain-rate and pressure dependency in the composite material model is accounted by the resin, which uses previously developed state-variable viscoplastic equations. These equations have been originally developed for metals, however are modified to account for the significant ...
A Non-orthogonal Material Model of Woven Composites in the Preforming Process
Weizhao Zhang, Huaqing Ren, Biao Liang, Jian Cao, Northwestern University, Evanston, IL, USA;
Danielle Zeng, Xuming Su, Jeffrey Dahl, Ford Motor Company, Dearborn, MI, USA;
Mansour Mirdamadi, Dow Chemical Company, Midland, MI, USA
dQiangsheng Zhao, Livermore Software Technology Corporation, Livermore, CA, USA
Woven composites are considered as a promising material choice for lightweight applications. The new LS-DYNA® material model MAT_COMPRM (MAT_293) that can decouple the strong tension and weak shear behavior of the woven composite under large shear deformation is developed for simulating the preforming of woven composites. The tension, shear and compression moduli in the model are calibrated using the tension, bias-extension and bending ...
A Peridynamic Model for Damage Prediction of Fiber-reinforced Composite Laminate
Bo Ren, C. T. Wu, Livermore Software Technology Corporation
This paper presents the keywords for a bond-based peridynamic model in LS-DYNA® to predict the damage of fiber reinforced composite laminates. To represent the anisotropy of a laminate by the peridynamic model, a lamina is simplified as a transversely isotropic media under the plane stress condition. The laminated structure is modeled by stacking the surface mesh layers along the thickness direction according to the laminate sequence. The bond ...
A Study in Mass Scaling for Sheet Metal Forming with LS-DYNA®
Jeanne He Du Bois and Paul Du Bois, Forming Simulation Technology LLC
Metal Forming simulation requires the deformed sheet metal to catch the tooling shapes precisely. With the limitation of lower order elements, mesh refinement is required to represent the key features of the geometry. In reality, the tooling travel speed is very low. Consequently, the physics of sheet metal forming involves a long termination time induced by the low Tool travel speed and a small timestep induced by the fine mesh. Many ...
A Study of Pedestrian Kinematics and Injury Outcomes Caused by a Traffic Accident with Respect to Pedestrian Anthropometry, Vehicle Shape, and Pre-Impact Conditions
Costin D. Untaroiu, Wansoo Pak, Yunzhu Meng, Virginia Tech, Blacksburg, VA, USA;
Berkan Guleyupoglu, Scott Gayzik, Wake Forest University, Winston-Salem, NC, USA
Pedestrians represent one of the most vulnerable road users. In the U.S., pedestrian fatalities show an increasing trend from 11% of total traffic fatalities in 2007 to about 15% in 2015. The rapid advancement in finite element (FE) technology, material testing, and computational power promotes FE car-to-pedestrian collision (CPC) simulations as a very useful component in the vehicle design process (e.g., in designing deployable devices for ...
A Study on Delamination Behavior between Aluminum and CFRTP
Masahiro Okamura, JSOL Corporation;
Shin Horiuchi, The National Institute of Advanced Industrial Science and Technology
In the near future, it is predicted that automobiles will use extensive amount of light weight material such as aluminum and CFRP. However, joining these material needs structural adhesive on the purpose of isolation and avoiding local stress concentration. In this paper, a simulation model has been built up using LS-DYNA® for DCB (double cantilever beam) test. Combination of various thicknesses in aluminum and CFRTP specimen has been studied to ...
A Study on Scatter during Production Process using Statistical Approach using LS-OPT®
Masahiro OKAMURA, JSOL Corporation
In recent years, robustness of car body structure has become more important than ever, as car manufacturers are required to achieve conflicting performance in high level such as light weight and crash performance. Major source of scatter in body structures are material scatter and production scatter. Since it is difficult to reduce scatter in material as certain range of scatter is allowed by industrial standard, tightening the quality control ...
A Survey of Eigen Solution Methods in LS-DYNA®
Roger Grimes, Liping Li, Eugene Vecharynski, Livermore Software Technology Corporation
LSTC has been adding several new methods for solving a variety of eigenvalue problems in LS-DYNA. This talk will give a survey of two new methods including MCMS (our implementation of the AMLS algorithm), and an iterative based method based on the Locally Optimal Block Pre-Conditioned Conjugate Gradients Method (LOBPCG). These methods will be contrasted with our standard method of Block Shift and Invert Lanczos. We will also describe our ...
A Temperature and Strain Rate Dependent Material Model with Tension-Compression Asymmetry for 0.25 inch Ti-6Al-4V Plate
Leyu Wang, Paul DuBois, Kelly Carney, Cing-Dao Kan, Center of Collision Safety and Analysis, George Mason University, USA
Tension-compression asymmetry observed in a 0.25" thick Titanium plate is modeled with *MAT_224_GYS, an isotropic elastic-thermo-viscous-plastic material model in LS-DYNA®. The input deck fits a series of tensile and compression tests at different strain rates and temperatures, conducted on samples cut from a 0.25" commercial off-the-shelf titanium plate. The rate and temperature dependent hardening law is separately defined for the tension ...
A Unified Environment for Collaborative CAE and Immersive Simulation Results Processing
Stavros Kleidarias, BETA CAE Systems S.A.
Ever since the first CAE simulations there has always been a need to examine digital models as close to reality as possible. Technology limitations meant that this was done on digital models with unrealistic graphics representation and on a PC monitor. Also, the evaluation of simulation results by engineering teams on different design centers was proven to be inefficient and time consuming, being based on exchanging tediously prepared images, ...
A Zero Thickness Cohesive Element Approach for Dynamic Crack Propagation using LS-DYNA®
Ala Tabiei, Wenlong Zhang, Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio 45221, USA
The zero thickness cohesive element approach for arbitrary crack propagation has a deficiency of introducing artificial compliance to the model, especially when cohesive elements are inserted into every element interfaces. For dynamic problems, the artificial compliance decreases the stress wave speed and makes the result less accurate. In this paper, the reason of the artificial compliance is examined, and the bilinear and exponential cohesive ...
ACP-OpDesign: Optimal Design Gateway: Reveal the Path to Optimized Products
A. Kaloudis, BETA CAE Systems International AG
ACP OpDesign is an intuitive and process-guided optimization desktop environment. With its optimization oriented and highly specialized user interface, based on the process depicted as a diagram in the tool, it offers the user the capability to take advantage of an efficient, direct interaction to: - ANSA’s powerful morphing and parametrization functionality - custom-designed META Post-processor tools - Topology and parametric optimization ...
Advanced Results Databases Compression Techniques to Allow their Efficient Use in Results Data Management Systems
Antonis Perifanis, Stelios Karapantazis, Dimitrios Krontsos, BETA CAE Systems S.A.
The usage of automated post processes is the rule nowadays. Simple scenarios include saving only specific LS-DYNA® results in post processing software native databases whereas in more sophisticated cases a series of report data are stored in data management systems. New challenges arose this way relevant to the need to download the report data from a data server as quickly as possible, display and compare them in the best way allowing in the ...
Advances in Fatigue Analysis with LS-DYNA
Yun Huang, Zhe Cui, Livermore Software Technology Corporation
Fatigue analysis is critical to the design and optimization of metal structures and components. This paper reviews the recent development in fatigue analysis with LS-DYNA. Both frequency domain and time domain fatigue solvers have been implemented to LS-DYNA. They can be used towards different simulation situations. Some examples are provided in this paper, to illustrate how to use these fatigue analysis methods. The plan on future development ...
Advances in LS-DYNA® for Metal Forming (I)
Xinhai Zhu, Li Zhang, Yuzhong Xiao, HouFu Fan, Livermore Software Technology Corporation
• Enhancements in *CONTROL_FORMING_ONESTEP • Smoothing of strain ratio (β) for failure prediction under nonlinear strain paths, with * CONTROL_ FORMING_TOLERANC • “Soft 6” contact improvement for gage pin contact • Weld line mapping with *INTERFACE_WELDLINE_DEVELOPMENT • Improvements in *BOUNDARY_SPC_SYMMETRY_PLANE (SET) • Improvements in springback compensation • Improvements in *ELEMENT_LANCING
Advances in LS-DYNA® for Metal Forming (II)
Li Zhang, Xinhai Zhu, Yuzhong Xiao, HouFu Fan, Livermore Software Technology Corporation
• New features in state output with *CONTROL_FORMING_OUTPUT • Automatic change from shell to thick shell elements with *CONTROL_FORMING_SHELL_TO_TSHELL • Define material hardening behavior in LS-DYNA with *DEFINE_CURVE_STRESS • Uniform mesh refinement inside a curve loop with *CONTROL_ADAPTIVE_CURVE • Vector option in *CONTROL_FORMING_BESTFI, and LS-PrePost® 4.5 Best-fit GUI • Sandwiched part mesh adaptivity • New capabilities in 2D and 3D ...
Airbag Folding with Generator4 and LS-DYNA® a Generic Process
Leyre Benito Cia, Christoph Kaulich, GNS-mbH (Gesellschaft für Numerische Simulation)
Generator4 is a pre-processor that helps users modeling the most complex CAE designs, from geometry handling and meshing to simulation definition. Characterized by its flexibility, this multi-platform software allows engineers to define calculations for the finite element solver LS-DYNA, as well as for multiple other solvers. Airbag modeling represents a great challenge for CAE Engineers, where complex processes with high accuracy demands ...
Airbag Folding with JFOLD Latest Developments and Case Studies
Richard Taylor, Ove Arup & Partners International Limited;
Toru Ishizuka, Mayumi Murase, Shinya Hayashi, JSOL Corporation
JFOLD is a software tool for simulation based airbag folding in LS-DYNA®. Today’s airbag deployment analysis demands accurate folding of complex designs, but this is often a very time consuming process requiring expert input. JFOLD’s continuous development focuses on making the process simpler and quicker and to give the non-expert access to complex folding techniques. This is achieved through three core elements: intuitive user interface, ...
Aircraft Seat Row-to-row Head Injury Criteria (HIC) Simulation Using LS-DYNA®
E-June Chen, PhD, Boeing Commercial, Seattle, Washington
Successful aircraft seat row-to-row HIC certification takes many test iterations and therefore is time intensive. Both developmental and certification tests are repeated to account for customized seat pitches, the range of occupant seated heights (from 5th percentile female to 95th percentile male), and several required impact zones. Row-to-row HIC prediction using simulation can help early design concept development (e.g., evaluating energy ...
Airdrop Sequence Simulation using LS-DYNA® ICFD Solver and FSI Coupling
Morgan Le Garrec, Matthieu Seulin, Vincent Lapoujade, DynaS+, Toulouse, France
In this framework, the payload freefall is considered for the present paper, from the airplane cargo bay up until the initiation of parachute deployment. The LS-DYNA simulations include multi-physics and fluid-structure interaction coupling. The currently developed ICFD solver is used in conjunction with the non-linear dynamic structural solver.
An Engineering Approach to Estimating Partially Saturated Soil Constitutive Properties Using LS-DYNA®
Len Schwer, Schwer Engineering & Consulting Services, 6122 Aaron Court, Windsor, California, 95492;
Matt Barsotti, Protection Engineering Consulting, 14144 Trautwein Road Austin, Texas 78737
Soil is perhaps the most common civil engineering material, and ironically one of the most difficult to model due to its variability. At any given site, soil samples taken at different depths and distances may show considerable variability. Even if such samples show relative uniformity, there is often the question of what happens if it rains and the soil saturation changes?
An Enhanced Assumed Strain (EAS) Solid Element for Nonlinear Implicit Analyses
Fredrik Bengzon, Thomas Borrvall, DYNAmore Nordic AB;
Ushnish Basu, Livermore Software Technology Corporation (LSTC)
Historically, the importance of computational efficiency in explicit analysis has driven the element development in LS-DYNA® [1,2] towards fast and sufficiently accurate formulations. Single point integrated elements with stabilization are well established techniques in this area. The recent growth of implicit analysis has led to a demand of increased accuracy of the element response, and consequently more sophisticated formulations have been ...
An Enhancement of LS-DYNA® XFEM Shells for Dynamic Ductile Failure Analysis
Y. Guo, C. T. Wu, W. Hu, Livermore Software Technology Corporation (LSTC), Livermore, CA 94551, USA;
K. Takada, H. Okada, utomobile R&D Center, Honda R&D Co., Ltd, Tochigi, 321-3393 Japan;
N. Ma, Center of Computational Welding Science (CCWS), Osaka University, Osaka, 567-0047 Japan;
K. Saito, Engineering Technology Division, JSOL Corporation, Tokyo, 104-0053, Japan
This paper presents an enhancement of LS-DYNA XFEM shell method [30] for dynamic ductile failure in shell structures. The XFEM shell formulation adopts the finite element continuous-discontinuous approach. The continuum damage model based on continuous displacements is used in the continuous stage to describe the diffuse micro-cracking in ductile failure before a macro-crack is formed. In the context of first-order shear deformable shell finite ...
Application of a Full-Field Calibration Concept for Parameter Identification of HS-Steel with LS-OPT®
Christian Ilg, André Haufe, David Koch, Katharina Witowski, DYNAmore GmbH;
Nielen Stander, Livermore Software Technology Corporation;
Åke Svedin, DYNAmore Nordic;
Mathias Liewald, Institut für Umformtechnik, Universität Stuttgart
In recent years results of digital image correlation (DIC) techniques have significantly improved in terms of accuracy, resolution as well as the speed of experimental strain measurement. The current availability of 2D or even 3D surface strain history during loading allows new approaches in constitutive parameter identification. In addition, localization (Fig 1.) exhibited in the numerical simulation can be integrated with DIC to identify ...
Bake-Hardening Effect in Dual-Phase Steels: Experimental and Numerical Investigation
David Koch, Filipe Andrade, André Haufe, DYNAmore GmbH, Stuttgart, Germany;
Markus Feucht, Daimler AG, Sindelfingen, Germany
Typically, the material characterization for the simulation is performed based on the virgin material which is used for the preparation of the corresponding component. However, due to the processing of the material, its mechanical properties may vary greatly. A typical example are materials subjected to forming operations. The work hardening during the forming process changes the local material properties such that the stress necessary for ...
Benchmarking Concrete Material Models Using the SPH Formulation in LS-DYNA®
Brian Terranova, Research Engineer, University at Buffalo;
Andrew Whittaker, Professor and MCEER Director, Department of Civil, Structural, and Environmental Engineering, University at Buffalo;
Len Schwer, Schwer Engineering & Consulting Services, 6122 Aaron Court, Windsor, California, 95492, U.S.
A model of a cylinder with a diameter and height of 400 mm was constructed in LS-DYNA using SPH particles to investigate the unconfined, quasi-static behavior of three concrete material models (i.e., MAT016, MAT072R3, and MAT159) in axial compression. Models were also prepared using Lagrangian solid elements and analyzed in axial compression to generate benchmark stress-strain data. Mesh refinement studies were conducted for the SPH cylinder to ...
Calculation of the Velocity and Shape of an Explosively Formed Projectile (EFP) Using Axisymmetric ALE
John Puryeara, Ben Harrison, ABS Group, 140 Heimer Rd. Suite 300, San Antonio, TX;
Lynsey Reesec, Michael Oesterle, NAVFAC Engineering and Expeditionary Warfare Center, Port Hueneme, CA
The symmetry common to most explosively formed projectiles (EFPs) permits their characterization using 2D axisymmetric analysis. Formation of an EFP entails volumetric expansion of the explosive and extensive plastic flow of the metal plate, both of which can be calculated using an Arbitrary Lagrangian Eulerian (ALE) method. Accordingly, the 2D axisymmetric ALE capability in LS-DYNA® was applied to calculate the velocity and shape of an EFP. The ...
Calibration of GISSMO Model for Fracture Prediction of A Super High Formable Advanced High Strength Steel
Xiaoming Chen, Guofei Chen, Lu Huang, Ming F. Shi, United States Steel Corporation
Advanced high strength steels (AHSS), due to their significantly higher strength than the conventional high strength steels, are increasingly used in the automotive industry to meet future safety and fuel economy requirements. Material failure that was rarely observed in crash tests a decade ago occurs more frequently in AHSS parts due to the relatively low ductility when compared to conventional steels. In computer aided engineering (CAE) ...
Cardiac Electrophysiology using LS-DYNA®
Pierre L’Eplattenier, Sarah Bateau-Meyer, Dave Benson, Livermore Software Technology Corporation, Livermore, California 94551;
Vikas Kaul, Carl Schu, Mark Palmer, Darrell Swenson, Joshua Blauer, Medtronic plc, Minneapolis, Minnesota 55432
Heart disease is among the leading causes of death in the Western world; hence, a deeper understanding of cardiac functioning will provide important insights for engineers and clinicians in treating cardiac pathologies. However, the heart also offers a significant set of unique challenges due to its extraordinary complexity. In this respect, some recent efforts have been made to be able to model the multiphysics of the heart using LS-DYNA.
CFD Validations with FDA Benchmarks of Medical Devices Flows
Chien-Jung Huang, Iñaki Çaldichoury, Facundo Del Pin, Rodrigo R. Paz, LSTC
Computational Fluid Dynamics (CFD) is a powerful tool and has been applied on various problems. In the biomedical application, CFD has been applied not only on the simulations of blood flow and airflow in lungs, but also on the designs and analysis of the medical devices. This study focuses on two benchmark problems proposed by FDA for the standardization of CFD simulation on the safety analysis on the blood-contacting medical devices, which is ...
Challenges of Predicting Impacts with Roadside Safety Hardware: Recent Case Studies
Akram Abu-Odeh, Texas A&M Transportation Institute, The Texas A&M University System College Station, Texas
As an integral part of engineering safer roads, road side safety devices passively interact with errant vehicles to redirect them safely back to the road or bring them to a safe and controlled stop. These devices take the form of crash cushions, cable barriers, concrete barriers, steel barriers, guardrails, guardrail terminals and others. Placement criteria and warrants are established in the AASHTO Road Side Design Guide (1). However, before ...
Characterization and Modeling of Spot-Weld Joints with *MAT_100_DA Parameter Optimization using LS-OPT®, and 3 Sheet Spot-weld Modeling Method Development in LS-DYNA®
Qaiser Khan, Hassan Ghassemi-Armaki, ArcelorMittal Global R&D, East Chicago, IN, USA;
Amandeep Singh Gill, Scott Zilincik, FCA Chrysler Technical Center, Auburn Hills, Michigan, USA;
Abhishek Gawade, Purdue University, Indianapolis, Formerly Intern at ArcelorMittal
Spot-weld strength is of crucial importance to the overall vehicle structural integrity and crash safety. With the innovation of Advanced High Strength Steels (AHSS), prediction of spot-weld fracture is of paramount importance in current and future vehicle designs. Spot-weld testing on AHSS intensive coupons was carried out in five different loading conditions, such as Tension-Shear, Coach-Peel, Cross-Tension and KSII configurations (30, 60 and ...
Classification-based Optimization and Probabilistic Analysis Using LS-OPT®
Anirban Basudhar, Imtiaz Gandikota, Livermore Software Technology Corporation, Livermore CA, USA;
Katharina Witowski, DYNAmore GmbH, Germany
LS-OPT is a standalone Design Optimization and Probabilistic Analysis package with an interface to LS-DYNA® that is capable of solving a variety of reliability assessment and single or multi-disciplinary design problems. It consists of a flexible framework with various methods that are suited to specific types of problems. The solution methods in LS-OPT are broadly categorized as direct or metamodel-based. Metamodel-based methods build ...
Cloud-based Pedestrian Protection App
Megha Seshadri, Naga Prasad Lagisetty, ESI Group
Democratize as the meaning says “make (something) accessible to everyone,” is the main objective of today’s industry to have simulations accessible to everyone to achieve significant improvements in development time and consistent outputs. In this paper we would like to present the workflow of a cloud-based Pedestrian Head Impact simulation. The Head Impact simulation will be executed through an embedded workflow, which internally executes ...
Combined Analysis of LS-DYNA® Crash-Simulations and Crash-Test Scans
Dominik Borsotto, Lennart Jansen, Clemens-August Thole, SIDACT GmbH
In robustness campaigns and optimization processes metamodels are created out of a set of crash-simulations. With the help of such analyses the models used for the simulations can be improved. For example, instabilities can be found and explained or the needed material can be minimized under certain safety restrictions.
Comparative Analysis of Occupant Responses between LS-DYNA® Arbitrary LaGrange in Euler and (ALE) and Structured–ALE (S-ALE) Methods
Venkatesh Babu, Kumar Kulkarni, Sanjay Kankanalapalli, Bijan Khatib-Shahidi, Madan Vunnam, U.S. Army, Research Development & Engineering Command, (RDECOM), Tank Automotive Research Development & Engineering Center (TARDEC), Warren MI 48397
The LS-DYNA ALE/FSI package can accurately model the dynamic response of the structure under blast loading. To simulate blast loading, High explosive, air and sometimes soil are modeled as different ALE materials which flow inside an ALE mesh that covers a spatial domain of our point of interest. If the spatial domain is of complex geometry, the ALE mesh is necessarily unstructured. But often times, the geometry is simply of a box shape so a ...
Comparison of Single Point Incremental Forming and Conventional Stamping Simulation
A. Belmont, R. Cruz, S. Fernandez, E. Quiroz and R. Perez-Santiago, Universidad de las Américas Puebla, Puebla, Mexico
This paper resumes simulation related aspects of one project aimed to compare two different sheet metal manufacturing technologies: Incremental Sheet Forming (ISF) and Conventional Stamping. Simulation of stamping in different stages of product development is an established practice in the industry, and the obtained results utilized to validate the process engineering before engaging in tooling fabrication. On the other hand, ISF simulations are ...
Computational Approach to Detect Instability and Incipient Motion of Large Riprap Rocks
Cezary Bojanowski, Steven Lottes, Transportation Research and Analysis Computing Center Nuclear Engineering Division, Argonne National Laboratory
Bridge scour is the process of removal of sediment from around bridge abutments or piers. In the most severe cases, scour leads to failure of bridges. One of the ways to stop or prevent the scour is to reinforce the riverbed by placing large rocks on the portion of the riverbed vulnerable to scour at bridge foundation structures (method called riprap installation). The sizing of riprap in scour countermeasure design is based mostly on limited ...
Computational Modeling of Adiabatic Heating in Triaxially Braided Polymer Matrix Composites Subjected to Impact Loading via a Subcell Based Approach
Christopher Sorini, Aditi Chattopadhyay, Arizona State University, Tempe, AZ, USA;
Robert K. Goldberg, NASA Glenn Research Center, Cleveland, OH, USA
The high rate deformation of polymer matrix composites is often accompanied by significant local adiabatic heating; in the case of ballistic impact loading, heat is generated locally within the polymer matrix due to the conversion of plastic work to heat, but the rapid nature of the event does not allow sufficient time for heat transfer to occur. In this work, a user-defined material subroutine implemented into LS-DYNA® to facilitate the ...
Constitutive Modeling of Biological Soft Tissues
Attila P. Nagy, David J. Benson, Livermore Software Technology Corporation, Livermore, CA 94551, USA;
Vikas Kaul, Mark Palmer, Medtronic plc, Minneapolis, MN 55432, USA
In the present communication, we introduce a class of material models primarily aimed at simulating the elastic and viscous behavior of biological soft tissues in LS-DYNA®. The constitutive law is modular and each module may comprise of different models. Consequently, the analyst may easily change models in a module and also include additional modules to account for more complex material behaviors within the same keyword. In its most general ...
Corrugated Fiber Board as a Packaging Material: Experimental and Numerical Analysis of the Mechanical Behavior
Chandra Sekhar Kattamuri, Madhukar Chatiri, Affiliations, CADFEM Engineering Services India Pvt.Ltd.
Corrugated Fiber Board (CFB) is a sandwich structure in which several paperboard materials, linerboard is glued to a sine wave shaped core, flute/corrugated medium. CFB packaging is a versatile, economic, light, robust, recyclable, practical and dynamic form of packaging. Boxes made from CFB are commonly used for the packaging of consumer goods, where better resistances to compressive forces, higher bending stiffness, better printability and ...
Crash Simulation of Mechanical Joints with Automatically Determined Model Parameters based on Test Results and Prediction Algorithms
S. Sommer, P. Rochel, Fraunhofer IWM, Germany;
M. Guenther, D. Herfert, Society for the Advancement of Applied Computer Science GFaI, Germany;
G. Meschut, P. Giese, Laboratory for material and joining technology LWF, Germany
The increasing usage of innovative light weight concepts in automobile production leads to the application of different mechanical joining techniques like self-pierce riveting- semi tubular (SPR-ST) and -solid (SPR-S), flow drilling screwing (FDS) and high speed bolt joining (HSB) for multi-material constructions. These mechanical joints are used at positions of car bodies which show high stresses under impact loading. For the prediction of the ...
Cure History Dependent Viscoelastic Modeling of Adhesively Bonded Joints using MAT_277 in LS-DYNA®
Akshat Agha, Fadi Abu-Farha, Rakan Alturk, Clemson University - International Center for Automotive Research, Greenville, SC, USA;
Tim Welters, Georges Romanos, Henkel Corporation, Düsseldorf, Germany
The effects of Coefficient of Thermal Expansion (CTE) mismatch in multi-material adhesive joints, induced during the manufacturing process, are expected to hinder the peak performance of the adhesive in the service life of the vehicle. With a goal to estimate these effects, this paper attempts to model the curing phenomenon of an adhesive and predict its mechanical properties using MAT_277 material model available in LS-DYNA, which serves as a ...
Damage and Failure Model Characterization for High Strength AA6000 Automotive Aluminium Alloys
Sebastijan Jurendic, Novelis Deutschland GmbH, R&D Centre Göttingen, Germany;
Richard Burrows, David Anderson, Novelis inc., Novelis Global Research and Technology Center, Kennesaw, USA
In this work we compare two different approaches for characterizing the GISSMO damage and failure model for high strength AA6000 series aluminium alloys using LS-DYNA®. The aim is to determine a consistent and reliable procedure for determining failure related mechanical properties of the material for use in automotive crash applications. The two approaches considered here are: a) an inverse numerical technique using LS-OPT® to solve an ...
Delamination Prediction and Non-local Averaging using a Composite Micro-Mechanical Model
Ala Tabiei, Sandeep Medikonda, Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio 45221, USA
Inter-laminar delamination in laminated composites has been studied with the help of thickness-stretch shell elements using a 3-D material model and compared against the traditional plane-stress shell elements. A strain-rate and pressure dependent micro-mechanical material model using ply-level progressive failure criteria has been used to simulate the initiation and propagation of delamination. The material parameters of the non-linear resin ...
Design Domain Dependent Preferences for Multi-disciplinary Body-in-White Concept Optimization
Nikola Aulig,Honda Research Institute Europe GmbH, Offenbach/Main, Germany;
Satchit Ramnath, Emily Nutwell, The Ohio State University SIMCenter, Columbus, OH, USA;
Kurtis Horner, Honda R&D Americas, Inc., Raymond, OH, USA
Recently methods for topology optimization are increasingly established in the virtual vehicle design process in the automobile industry. In particular a heuristic topology optimization process based on the assumption of uniform energy distribution throughout the structure combined with a scaled energy weighting approach was demonstrated to successfully to provide concepts for vehicle structures subject to static and crash loads concurrently. ...