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15th International LS-DYNA Conference

Detroit, 2018

Scalability Study of Particle Method with Dynamic Load Balancing
Hailong Teng, Livermore Software Technology Corp.
We introduce an efficient load-balancing algorithm for particle method (Particle Blast method and Corpuscular Particle method) in LS-DYNA®. Load-balancing is achieved by dynamically adaptively using RCB to evenly distribute workload to processors. Numerical tests demonstrated that with reformulated parallel scheme, for PBM, the speedup for an airblast problem can be 20~30 times or more when using 128~192 cores; for CPM, several times speed up ...
Shape Optimization with LS-DYNA® Suite For MDO (Multidisciplinary Design Optimization)
Ryo Ishii, JSOL;
Masayoshi Nishi, Nihon Emsco Co. Ltd.
LS-DYNA has been able to optimize several different calculations to meet each criterion with LS-OPT® freely. In previous year, we showed MDO (Multidisciplinary Design Optimization) would be great powerful solution that LS-DYNA suite including LS-OPT and LS-PrePost® would be able to solve crucial problem during development of product. In this study, we are trying shape optimization to solve trade-off which occurs in the process of product ...
Sheet Metal Forming Simulation with IGA in LS-DYNA®
Stefan Hartmann, DYNAmore GmbH, Stuttgart, Germany;
David J. Benson, Liping Li, Attila P. Nagy, Livermore Software Technology Corporation, Livermore, CA, USA
In the last few years, numerous research work has been devoted to Isogeometric Analysis (IGA). IGA is a finite element technology in which computer-aided design (CAD) geometric description is invoked to perform numerical analysis. The most widely used mathematical description in CAD is non-uniform rational B-splines (NURBS) and therefore NURBS-based shell and solid finite elements have been implemented into LS-DYNA.
Simulation and Testing Assessment of Cruciform Parachutes using LS-DYNA® ALE
Terence Rose, Gregory Noetscher, Keith Bergeron,
U.S. Army Natick Soldier Research, Development & Engineering Center
This work presents a model of the coupled aero- and structural dynamics for a cruciform parachute which can then be used to inform development of control schemes for autonomously guided airdrop systems. Currently, the United States Army uses a combination of ram-air parachutes, as part of the Joint Precision Airdrop System (JPADS), and ballistic unguided parachutes to deliver supplies in austere locations. Ram-air parachutes are highly ...
Simulation of Overhead Crane Wire Ropes Utilizing LS-DYNA®
Andrew Smyth, P.E., LPI, Inc., New York, NY, USA
Overhead crane wire ropes utilized within manufacturing plants are subject to extensive cyclic loading due to near continuous service operation. An LS-DYNA model was developed to assist in determining the expected fatigue life of the crane wire ropes by calculating both the dynamic cyclic stress and the total number of bending reversals per lift.
Simulation of Self-Piercing Rivet Insertion Using Smoothed Particle Galerkin Method
Li Huang, Shiyao Huang, Materials and Process Research, Ford Motor Research and Engineering Center;
Youcai Wu, Livermore Software Technology Corporation;
Garret Huff, Andrey Ilinich, Amanda Freis, George Luckey, Research and Advanced Engineering Center, Ford Motor Company
Self-piercing rivets (SPR) are efficient and economical joining elements for lightweight automotive body structures. In this paper, a meshfree Smoothed Particle Galerkin (SPG) method was applied to the simulation of the SPR insertion process. Two layers of aluminum alloy 6111-T4 were joined using a full three-dimensional (3D) model with LS-DYNA® explicit. The severely deformed upper sheet was modeled using the SPG method with activated bond ...
Simulation of the Braiding Process in LS-DYNA®
Seyedalireza Razavi, Lorenzo Iannucci, Imperial College London, Department of Aeronautics, London, UK
Textile braids and the over-braiding manufacturing technology have been attracting a lot of recent interest, particularly in the aerospace and automotive industries, in response to increasing demands for a low cost manufacturing process to produce high-performance composites. The application areas extend from the over-braided structural components of super-cars (e.g. Lamborghini Aventador) to 2D and 3D triaxial braided composite fuselages, ...
Simulation of the Performance of Passenger Rail Vehicles under Blast Conditions in LS-DYNA®
Francois Lancelot, Ian Bruce, Devon Wilson, Kendra Jones, Arup
Przemyslaw Rakoczy , Transportation Technology Center Inc.
The protection of the national transportation systems in the face of increasing terrorist threats is of critical importance. Arup North America Ltd (Arup) and Transportation Technology Center, Inc. (TTCI) have been contracted to conduct research to quantify the vulnerability of railcars and infrastructure to damage caused by the use of explosives. The main objectives of this ongoing research program is to develop tools to evaluate the ...
Smoothed Particle Galerkin Method with a Momentum-Consistent Smoothing Algorithm for Coupled Thermal-Structural Analysis
X. Pan, C.T. Wu, W. Hu, Y.C. Wu, Livermore Software Technology Corporation
This paper introduces a momentum-consistent smoothing algorithm to Smoothed Particle Galerkin (SPG) method [1] in LS-DYNA® for the coupled thermal-structural analysis. In contrast to the kernel approximation in conventional Lagrangian particle methods, the system of equations of the present method is discretized and approximated following that in the SPG method. The momentum-consistently smoothing algorithm provides the desired stability and ...
Sound Absorbing Porous Material in Statistical Energy Analysis
Zhe Cui, Yun Huang, LSTC Livermore California USA;
Mhamed Souli, Lille University France;
Tayeb Zeguar, Jaguar Land Rover UK
For high frequency analysis, Statistical energy analysis (SEA) has proved to be a promising approach to the calculation of sound transmission in complex structures. In automotive industry and also in civil engineering, most of noise transmission is due to high-frequency structural vibrations, where the characteristic wavelength is small compared to the dimensions of the structure. For these applications classical methods of structural analysis, ...
Strain Rate and Temperature Dependent Testing in Support of the Development of MAT224 and MAT213
Amos Gilat and Jeremy Seidt, The Ohio State University Department of Mechanical and Aerospace Engineering, Columbus OH, USA
The deformation and failure of metals and composites is known to be affected by strain rate and temperature. Material models in LS-DYNA® account for these effects and material coupon testing is required for determining the input parameters for the models. The present paper presents a new experimental setup that provide means for investigating the coupled effects of temperature and strain rate during plastic deformation, and new strain rate ...
Stretching Failure Prediction in LS-PrePost® by a SCL Realized Ductile Failure Criterion
Z.Q. Sheng, Body Manufacturing, General Motors Company
The LS-PrePost Scripting Command Language (SCL) is a C like computer language that executed inside LS-PrePost. The SCL enables user to process the simulation results and visualize the resultant data back in the LS-PrePost. In this study, the SCL is used to realize a proposed ductile failure criterion (DFC). With the help of the SCL, the stretching failure in the draw simulation results can be predicted. The effectiveness of SCL is demonstrated ...
Study of Drop Test Parameters Using Design of Experiments
Pritesh Jain, Rushab Oswal, Ameya Khisty, Tata Technologies Ltd
Various products such as refrigerators, mobile phones, televisions, washing machines, remote controls, telecommunication and military equipment, etc. are subjected to drop tests to assess their fragility and impact tolerance. It is difficult and expensive to understand the effect of various parameters that affect product performance during the test. Finite element simulations using LS-DYNA® effectively help to understand the effect of these ...
Subject-Specific Modeling of Human Ribs: Finite Element Simulations of Rib Bending Tests, Mesh Sensitivity, Model Prediction with Data Derived From Coupon Tests
Keegan Yates, Costin Untaroiu, Virginia Tech, Blacksburg, VA, USA
Rib fractures are common thoracic injuries in motor vehicle crashes. The main objective of this study was to investigate the predictability of subject specific rib models under bending loading. The exterior geometries of two human ribs as well as the boundaries between the trabecular and cortical layers were extracted from corresponding CT-images. Then, the mesh of one rib was developed in a parametric fashion. To investigate the mesh influence ...
Test Validated Multi-Scale Simulation of a Composite Bumper Under Impact Loading
Cody Godines, Frank Abdi, Saber Dormohammadi, Michael Lee, AlphaSTAR Corporation, Long Beach, California;
Akbar Farahani, Morteza Kiani, Engineering Technology Associates, Inc. Troy, Michigan
In a recent USAMP-DOE Validation of Material Models study sought to evaluate efficacy of computational software against physical test. The undertaking started with material characterization and sub-element verification in Phase I and continued to full bumper assembly evaluations. A multiscale ICME building block approach for calibration, verification, and validations resulted in good agreement between test and simulation and served as the ...
The Effect of Inconel-718 High Strain Rate Sensitivity on Ballistic Impact Response using *MAT_224
Stefano Dolci, Kelly Carney, Leyu Wang, Paul Du Bois, Cing-Dao Kan, Center for Collision Safety and Analysis, George Mason University, Fairfax, VA
A research team from George Mason University, Ohio State University, NASA and FAA has developed material data and analytical modeling that allows for precise input of material data into LS-DYNA® using tabulation and the *MAT_224 material model. The input parameters of this model are based on data from many experimental coupon tests including tension, compression, impact, shear and biaxial stress states. The material model also includes ...
The Immersed Smoothed Particle Galerkin Method in LS-DYNA® for Material Failure Analysis of Fiber-Reinforced Solid Structures
Wei Hu, C. T Wu, Livermore Software Technology Corporation;
Shinya Hayashi, JSOL Corporation
This paper presents a novel immersed meshfree approach [1-3] for modeling and failure analysis of fiber-reinforced composite solids. The fiber and solid parts are discretized by finite element truss/beam and solid element formulations respectively and independently. This modeling process does not require a conforming mesh. In other words, the fiber elements, e.g. truss or beam elements, are embedded into FEM mesh for immerse computation. The ...
The Investigation of Parachute Suspension Line Fluid-Structure Interactions using LS-DYNA® ICFD
Catherine P. Barry, Bradford G. Olson, David J. Willis, James A. Sherwood, University of Massachusetts Lowell;
Keith Bergeron, U.S. Army Natick Soldier Research, Development & Engineering Center
The U.S. Army uses autonomously guided parachute systems to deliver supplies to troops in the field. Each system consists, primarily, of a lightweight canopy, braided polyester suspension lines, and payload. As a system descends, the suspension lines generate and shed vortices as a result of the cross-flow of air, and these vortices induce fluctuating drag and lift forces. These fluctuating forces introduce system performance degradations, and ...
The Role of LS-DYNA® in the Design of the New London Electric Taxi
Jamie Dennis, Simon Hart, Arup (Advanced Technology and Research), Solihull, UK
The iconic London taxi is known worldwide. The London Taxi Company (LTC) has produced this much loved vehicle for many years with few radical changes. Recently, zero-emission legislation in London and the global demand for cleaner vehicles has prompted an evolution in its design. With investment from owner Geely, the newly branded London EV Company (LEVC) will produce several thousand electric taxis per year from its new headquarters in ...
Theoretical and LS-DYNA® Analysis of Springback Effect on U-Shape Part Top Shape
Zhiguo Qin, Ching-Kuo Hsiung, General Motors
In our AHSS U-Shape part springback study, small curvature on the U-Shape part flat top was observed after spring-back. Two mechanics models were used to explain the top bending and unbending deformation processes and the top curve forming mechanism. LS-DYNA simulation results and theoretical analysis results have good correlation. Based on the analysis, 5 methods were proposed to control the flat top spring-back.
Thermo-Mechanical Approach Using LS-DYNA® to Predict Tool Shape for Insert Molded ARPRO® (EPP) Rear Seat Cushion/Riser
Nurul Huda, JSP International
Shrinkage and warpage is widely observed phenomenon in molding process where parts are molded at a higher temperatures than the ambient temperature. This paper demonstrates thermo-mechanical approach in aiding to design an insert molded ARPRO® (EPP) seat cushion. When the molded ARPRO® seat cushion is being ejected from press at high temperature than ambient, and, cools down to ambient temperature - it deforms due to thermal shrinkage. This ...
Three -Dimensional Integrated Simulation for Composite Sheet Compression Molding
Jim Hsu, Srikar Vallury, Anthony Yang, Moldex3D Northern America Inc., MI
Sheet molded composite (SMC) or glass-mat-reinforced thermoplastic (GMT) material is widely used in the automotive industry with the compression molding process to achieve a higher residual length of the glass strands. In this work, an integrated simulation procedure is developed for SMC/GMT composite compression process. First, LS-DYNA® is used to conduct the draping analysis to predict the deformed shape of the initial charge before ...
Topology Optimization of a Stamping Die Structure using LS-DYNA® and LS-TaSC™
Jithesh Erancheri, Ramesh Venkatesan, Nanda Kumar, Kaizenat Technologies Pvt Ltd
Cost of Stamping Dies accounts for about 45% of total cost of a vehicle program. The construction cost of these dies is used as benchmark by the automotive companies to evaluate the cost of any new vehicle program and also to determine where they stand compared to their competitions. The cascading effect goes down to the TIER-1 suppliers to optimize their die structure designs in order to stay afloat in the business. FE Simulation tools like ...
Towards an Automatic Evaluation of a Car Floor Module in a Pole Crash Load Case
Verena Diermann, Christoph Boese, Pascal Schlaak, Daimler AG;
Prof. Dr.-Ing. Peter Middendorf, Institute of Aircraft Design, University of Stuttgart
Nowadays crashworthiness simulations are regarded as not suitable for optimization. One reason is the lack of hard evaluation criteria. A small part of the evaluation of crashworthiness simulations is done by comparing numerical criteria to given boundaries. The larger part of the evaluation consists of visual evaluation based on engineering experience. This visual evaluation on the one hand contains the influence of the engineer’s subjective ...
Transient Dynamics of Slicing-Impact Loading on Jet Engine Fan Blades during a Bird-strike Event
Sunil K. Sinha, Ph.D., Adjunct Faculty, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, 43210-1142
Based upon numerous field events involving bird-strikes on aircraft propulsion system components, the engine manufacturers have long recognized the need for better understanding and insight in the physics of slicing action for analytically predicting the damage to the fan blade. A medium or large size bird being ingested in a running engine with aircraft velocity in the range of 100-120 m/second, essentially during the take-off time, is capable ...
Tube Adaptivity for Mesh Fission/Fusion in LS-DYNA®
Xinhai Zhu, Houfu Fan, Li Zhang, Yuzhong Xiao, Livermore Software Technology Corporation;
NinShu Ma, Osaka University
A new feature named tube adaptivity for sheet metal forming is implemented in LS-DYNA. It conducts adaptive mesh fission/fusion at the beginning of an adaptive step according to a predefined load path and a set of user defined parameters. Automatically mesh refinement is carried out in the neighborhood of the tool path. Tube adaptivity can help in reducing the computational time of incremental forming or roller hemming while maintain the overall ...
U-splines for Unstructured IGA Meshes in LS-DYNA®
Dr. Michael Scott, Brigham Young University, Coreform LLC
The isogeometric analysis (IGA) paradigm [5] eliminates the CAD/CAE data translation problem by using the CAD geometry directly as a basis for analysis. IGA was introduced by Dr. Thomas J.R. Hughes et. all in 2005 (Dr. Hughes is now a senior advisor and co-founder of Coreform), and has produced over 1500 academic papers to date, multiple annual conferences dedicated to IGA, and numerous eye-popping results [7]. In other problems, it gives an ...
Update on Resistive Spot Welding Capabilities in LS-DYNA®
Iñaki Çaldichoury, Pierre L’Eplattenier, Sarah Bateau-Meyer, LSTC, Livermore, USA;
Tobias Loose, DynaWeld GmbH & Co. KG, Germany;
Uwe Reisgen, ISF - Welding and Joining Institute, RWTH - Aachen University, Germany
Resistance Spot Welding (RSW) is a very important welding process for thin sheet metals with many applications, in particular in the automotive industry. In this method, the contacting metal surfaces are joined by the heat obtained by Joule heating of an electrical current flowing through resistances. These resistances are composed of the bulk resistance of the parts being welded, and of the contact resistances at the interfaces between the ...
Using MAT213 for Simulation of High-Speed Impacts of Composite Structures
Loukham Shyamsunder, Bilal Khaled, Canio Hoffarth and Subramaniam D. Rajan,
School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ;
Robert K. Goldberg, NASA-GRC, Cleveland, OH;
Kelly S. Carney and Paul DuBois, George Mason University, Fairfax, VA;
Gunther Blankenhorn, LSTC, Livermore, CA
A general purpose orthotropic elasto-plastic computational constitutive material model has been developed to predict the response of composites subjected to high velocity impact. The three-dimensional orthotropic elasto-plastic composite material model is being implemented in a special version of LS-DYNA® for solid elements as MAT213. In order to accurately represent the response of a composite, experimental stress-strain curves are utilized as ...
Verification of Sound Absorption Characteristics Constituted Porous Structure
Toru Yoshimachi, Ryo Ishii, SOL Corporation, Japan;
Kuniharu Ushijima, Naoki Masuda, Tokyo University of Science, Japan;
Takao Yamaguchi, Gunma University, Japan;
Yun Huang, Zhe Cui, Livermore Software Technology Corporation, USA
This paper presents the verification the level of acoustic solver in LS-DYNA® and availability of LS-DYNA evaluating acoustic issue interior problem. We made sound in a Rectangular empty box made from aluminum and measured sound there by microphone in order to compare the experiment and simulation. We prepare fundamental material as sound absorption and attached it to the Rectangular empty box. In LS-DYNA, The characteristics of the sound ...
Virtual Ballistic Testing of Kevlar Soft Armor: Predictive and Validated Modeling of the V0-V100 Probabilistic Penetration Response using LS-DYNA®
Gaurav Nilakantan, Teledyne Scientific & Imaging, Thousand Oaks, CA 91360, USA
Over 15 years of worldwide research into the ballistic impact modeling of woven aramid fabrics used in soft armor based on yarn-level fabric finite element models has been unable to achieve any quantitatively-predictive and validated capability to predict the V0-V100 probabilistic penetration response of the fabric against various threats. For the first time ever, we demonstrate such a capability and the comprehensive framework behind it that ...
Workflow-based Material Characterization for LS-DYNA® in d3VIEW
Suri Bala, LSTC and d3VIEW;
Paul Du Bois; Independent Consultant;
Shashank Dhanakshirur, d3VIEW
Abstract Characterization of material models involves a series of operations, verifications and eventual use of developed material card in simulation models. LS-DYNA presents over 300 material models and provides a wide-variety of materials that can be modeled. In this paper, we hope to present a workflow based material characterization in d3VIEW for Metals, Polymers, Cellular Solids, and Elastomers. A simple workflow example will be included ...
Zoning Method for Efficient Material Properties Calculation
J. Kronsteiner and E. Kabliman, Leichtmetallkompetenzzentrum Ranshofen GmbH, AIT Austrian Institute of Technology GmbH, Lamprechtshausenerstr. 61, 5282 Braunau am Inn - Ranshofen, AUSTRIA.
When material models are enhanced by calculating additional effects such as microstructure evolution for every Gauss point and time step, considerable numerical effort must be expected. Interfacing third-party software from within user defined material subroutines can even be more time consuming. In many applications, however, considerable parts of the material domain give similar results. Strain, strain rate and temperature are the most ...