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8th International LS-DYNA Conference

LS-DYNA Implicit for Dent Performance Evaluation
Gagan Tandon, Venugopal Bachu - Altair Engineering Inc.
Present day engineering design involves complex CAE analyses using both linear and non-linear methods. Mos companies use multiple software tools for different types of analyses. Several reasons, including cost are driving companies to investigate lesser number of FEA tools so that they can use a single solver for most of their structural analyses. LS-DYNA has been traditionally used for explicit analysis like crash and metal forming. ...
Numerical Modeling of Woven Carbon Composite Failure
Paul F. Deslauriers, Duane S. Cronin - University of Waterloo
Alex Duquette - Multimatic Technical Centre
This paper presents application of a MLT-based (Matzenmiller, Lubliner, Taylor) approach to model damage in woven carbon composite materials. The MLT formulation has been adapted to shell elements to model individual composite plies. The implementation of the model is discussed along with simple test cases to demonstrate the material response and limitations within the original MLT model. One of these limitations has been addressed through ...
Effect of Triggering Mechanism on the Load-Displacement Response and Folding Pattern of Square Aluminum Tubes
H. El-Hage, N. Zamani - University of Windsor, Canada
P. K. Mallick - University of Michigan-Dearborn, USA
A systematic numerical investigation of the effect of triggering mechanism on the load-displacement characteristics and lobe formation of square aluminum tubes subjected to quasi-static axial compressive load is presented. Among the physical triggering mechanisms considered were chamfering, drilled holes, geometric imperfection and combinations thereof. The effect of corner radius was also considered. This study has shown that the ...
Simulation of Cure Volume Shrinkage Stresses on Carbon/Vinyl Ester Composites in Microindentation Testing
Tom Mase, Lanhong Xu, Lawrence T. Drzal - Michigan State University
Composites made with carbon fibers and vinyl ester have significant higher processing volume shrinkage compared to composites made with epoxies. During the curing, vinyl esters experience as much as three times the volume shrinkage as compared to epoxies (10 %Vol versus 3-4 %Vol). This difference in cure volume shrinkage may be the reason that the mechanical properties of carbon/vinyl esters are low compared to that of carbon/epoxy. ...
Development of an LS-DYNA Model of an ATR42-300 Aircraft for Crash Simulation
Karen E. Jackson, Edwin L. Fasanella - U.S. Army Research Laboratory
This paper describes the development of an LS-DYNA simulation of a vertical drop test of an ATR42-300 twin- turboprop high-wing commuter-class airplane. A 30-ft/s drop test of this aircraft was performed onto a concrete impact surface at the FAA Technical Center on July 30, 2003. The purpose of the test was to evaluate the structural response of a commuter category aircraft when subjected to a severe, but survivable, impact. The aircraft was ...
A Numerical Investigation into HIC and Nij of Children for Forward and Rearward Facing Configurations in a Child Restraint System
William Altenhof, Rita Turchi - University of Windsor
This study explores the various differences in potential for injury in 3-year-old children in the case of a frontal collision. A crash analysis between forward and rearward facing children, both restrained in a five-point child restraint, was performed using numerical simulation methods. This comparison was carried out by conducting numerical simulations of these situations using the criteria outlined in FMVSS 213. The injuries that were ...
FEM for Impact Energy Absorption with Safety Plastic
Iulian Lupea, Joel Cormier, Sital Shah - The Oakwood Group
For the engineering design process to benefit from finite element modeling (FEM), it must adequately represent any condition being studied. This paper presents methodologies for using the LS-DYNA non-linear finite element solver to model a patented energy absorbing technology called SafetyPlastic®. SafetyPlastic® offers a performance, cost, and mass competitive energy management solution, and has been embraced by the automotive industry in ...
Implementation of Modal Representation for Full Vehicle VPG Simulations
Xianggang Zhang - Engineering Technology Associates, Inc.
The modal representation method matured in LS-DYNA 970. It is a useful tool for full vehicle, long duration Virtual Proving Ground (VPG) analyses. The CPU time for VPG analysis could be dramatically reduced with such application. Modal representation method uses linear combination of the pre-calculated mode shapes to represent portion of the full vehicle model in transient dynamic analysis. The linear modal response of this portion of ...
IIHS Side Impact Analysis Using LS-DYNA/Madymo Coupling
Jiri Kral - TNO Madymo North America
Prabhu Setru, Swarna Rajeswaran - General Motors
The LS-DYNA/Madymo coupling has a growing popularity in the field of vehicle crash analysis as it allows the users to merge an existing occupant simulation subsystem model and a full car structural model into one system. The extended coupling feature introduced in late 2002 has significantly enhanced this model fusion capability. This paper demonstrates the application of such a coupling technique for the simulation of the IIHS ...
Influence of Pre-Stressed Parts in Dummy Modeling - Simple Considerations
Ulrich Franz, Peter Schuster, Sebastian Stahlschmidt - DYNAmore GmbH
New regulations and consumer tests for passive safety in passenger cars have increased the de- mand on accurate models for occupant analysis. Thus, effects that have been neglected or mod- eled rather coarsely in recent occupant models might necessitate a more detailed modeling in order to capture the dummy behavior sufficiently accurate. This paper contributes to the discussion of the importance and the modeling techniques of pre- stressed ...
A FE Modeling and Validation of Vehicle Rubber Mount Preloading and Impact Response
Sae U. Park, Madhu R. Koka, Kevin R. Thomson, Jeffrey L. Robbins - DaimlerChrysler Corporation
A variety of rubber mounts are being used for vehicles as isolators/dampers between body and frame, on the engine cradle, etc. It has been the prevalent CAE practice in the auto industry to evaluate the mounts’ high-speed vehicle crash response by the means of nonlinear spring/beam models. However, the simplified models carry a risk of generating incomplete and erroneous results, especially under very complex crash loadings due to the absence ...
A Benchmark Study of CAE Sensor Modeling Using LS-DYNA
C. C. Chou, P. Chen, J. Le - Passive Safety R&A, Ford Motor Company
Nasser Tamini - ETA
This paper presents results from a benchmark study of CAE sensor modeling using LS-DYNA. Using the VPG translator, a sensor model was converted from a calibrated RADIOSS model into LS-DYNA input formats for frontal impact simulations carried out in this study. Since two codes have different material laws, element library and functionalities, those deemed to be as closed to RADIOSS were chosen in the translation process. For those that could ...
Study of a Driver Airbag Out-Of-Position Using ALE Coupling
Wenyu Lian - General Motors
Dilip Bhalsod - Livermore Software Technology Corporation
The new FMVSS 208 regulation specifies the airbag performances under Out-of-Position conditions. During the past 10 years, the thermodynamic-based airbag models have been successfully used in analyzing the occupant interaction with the airbag under regular crash conditions (in-position). However, these models are not suitable for the airbag OOP applications since they can not accurately predict the flow forces that dominate the ...
An Investigation of Structural Optimization in Crashworthiness Design Using a Stochastic Approach
Larsgunnar Nilsson, Marcus Redhe - Engineering Research Nordic AB, Sweden
In this paper the Response Surface Methodology (RSM) and the Stochastic Optimization (SO) are compared with regard to their efficiency and applicability in crashworthiness design. Optimization of simple analytic expressions and optimization of a front rail structure are application used in order to assess the respective qualities of both methods. A low detailed vehicle structure is optimized to demonstrate the applicability of the methods in ...
Robustness Study of an LS-DYNA Occupant Simulation Model at DaimlerChrysler Commercial Vehicles Using LS-OPT
Dr. Frank C. Günther - DaimlerChrysler
Dr. Heiner Müllerschön, - DYNAmore GmbH
Dr. Willem Roux - Livermore Software Technology Corporation
The robustness properties of crash simulation models are emerging as an important criterion in today's simulation driven vehicle development process. We consider it relevant to any study of highly non-linear crash problems to obtain measures for the repeatability and reliability of both experimental and numerical tests. In 2003, we conducted a robustness study of a structural front impact model (JAPAN LS-DYNA Users Conference 2003) using ...
Horizontal Tailplane Subjected to Impact Loading
M. Hörmann, U. Stelzmann - CAD-FEM GmbH, Germany
M.A. McCarthy - University of Limerick, Ireland
J.R. Xiaoc - University of Delaware, USA
The European Union Research Programme CRAHVI (CRashworthiness of Aircraft for High Velocity Impact) is concerned with the high velocity impact of aircraft due to flying objects, e.g. bird, hailstone, tyre and engine debris as well as concerned with survivable crash landings on different surfaces, e.g. rigid inclined surfaces (slopes) and water with different sea states. The simulation is naturaly a complex task due to the high number of ...
Crashworthiness Design of Vehicle Structures via Equivalent Mechanism Approximations
Karim Hamza, Kazuhiro Saitou - University of Michigan
A new method for crashworthiness optimization of vehicle structures is presented. In the new method, early design exploration is done by the optimization of an equivalent mechanism approximating a vehicle structure. An equivalent mechanism (EM) is a network of rigid bodies connected by prismatic and revolute joints with special nonlinear springs. These springs are tuned to mimic the force-displacement characteristics of thin-walled ...
LS-OPT Capabilities for Robust Design
Nielen Stander, Willem Roux - Livermore Software Technology Corporation
This paper presents a number of new features available in LS-OPT Version 2.2. As a step toward robust design, the code has been extended to enable reliability assessment and the identification of sources of unpredictability in the FE model. In the latter feature, deterministic and stochastic effects can be separated.
ALE and Fluid Structure Interaction in LS-DYNA
M. Souli - Laboratoire de Mécanique de Lille
J. Wang, I. Do, C. Hao - Livermore Software Technology Corporation
Fluid-structure interactions play an important role in many different types of real-world situations and industrial applications involving large structural deformation and material or geometric nonlinearities. Numerical problems due to element distortions limit the applicability of a Lagrangian description of motion when modeling large deformation processes. An alternative technique is the multi-material Eulerian formulation for which ...
The Effects of Numerical Result and Computing Time Due to Mass Scaling in Rolling Analysis
J.Y. Chin, S.W. Lee, S.H. Paik, W.S. Chung - Theme Engineering Inc.
To enhance the structural performance for vehicle, a patch is attached. For various section shapes, each patch has different performance in energy absorption. In despite of efficient patch, formability may be a problem. Because the depth of groove is about 0.2mm, it needs a large FEM model for rolling analysis and has very small time step. We have to choose a method to reduce analysis time. This paper presents the effects of mass scaling in ...
Investigation of the Arbitrary Lagrangian Eulerian Formulation to Simulate Shock Tube Problems
C.P. Salisbury, D.S. Cronin, F.S. Lien - University of Waterloo
A critical step in modeling complex problems using numerical simulations is validating the numerical approach using simplified problems. The current study investigates application of the Arbitrary Lagrangian Eulerian (ALE) formulation, as implemented in LS-DYNA, to simulate a pseudo 1-D shock tube problem. The shock tube problem was selected since analytical results can be directly determined from the initial conditions. A shock tube is ...
Modeling of Fuel Sloshing Phenomena Considering Solid-Fluid Interaction
Jean Ma, Mohammad Usman - Plastics Products and Processing CAE Visteon Corporation
The sloshing phenomenon in partially filled fuel tanks is more pronounced when vehicles experience a sudden start or stop. Sloshing is un-desired because it produces noise, high impact force on the tank walls and the challenge of low fuel handling. Today, the solution for containing sloshing is to incorporate baffles inside the tank. The presence of baffle dissipates the energy that is induced by the fuel motions. Design of baffles is a ...
The Use of LS-DYNA to Simulate the Water Landing Characteristics of Space Vehicles
Benjamin A. Tutt, Anthony P. Taylor - Irvin Aerospace Inc
Irvin Aerospace, Inc. has been involved with the recovery/landing systems of re-entry and interplanetary space vehicles spanning a number of years. A significant aspect in the assessment of recovery and escape systems is the performance of such vehicles in the event of a water landing. One method used to reduce the loads imparted to the crew as the vehicle enters the water is to increase the drag area of the falling body. Increasing the drag ...
A Mesh-free Analysis of Shell Structures
C. T. Wu, Yong Guo - Livermore Software Technology Corporation
Hui-Ping Wang, Mark E. Botkin - General Motors
A mesh-free formulation based on the Mindlin-Reissner shell theory for geometrical and material nonlinear analysis of shells is presented. In this mesh-free formulation, two projection methods are developed to generate the shell surface using the Lagrangian mesh-free interpolations. The updated Lagrangian theory underlying the co-rotational procedure is adopted for the local strain, stress and internal force updating. A local boundary ...
Improved LS-DYNA Parallel Scaling From Fast Collective Communication Operations on High-Performance Compute Clusters
Lars Jonsson, Tim Prince - Intel Corporation
Fast collective communications are a key to maintaining high parallel efficiency as the number of nodes increases on a cluster of high-performance servers. Profiling of LS-DYNA message traffic demonstrates that good parallel scaling requires fast communications of short messages - up to a few kilobytes - and in particular of collective operations involving short messages. Fast collective operations require both an efficient implementation of ...
Benefits of Scalable Server with Global Addressable Memory for Crash Simulation
Christian Tanasescu, Nick Meng - SGI Inc.
A wide variety of industries rely on mechanical computer-aided engineering (CAE) to improve design quality, reduce design-cycle time, and control costs. In designing automobiles, the manufacturers must meet different government regulations for vehicle safety. The maturity of Explicit Finite Element methods and the increasing computational power of today's computers have allowed the automotive industry to incorporate the Crash simulation ...
Improved LS-DYNA Performance on Sun Servers
Youn-Seo Roh, Henry H. Fong - Sun Microsystems, Inc.
Current Sun platforms which are very competitive in price/performance include Linux servers using either the Intel Xeon or AMD Opteron processors. Benchmark results using the industry-standard Neon model are presented. Performance and scalability up to 32 CPU's are discussed, as well as a comparison of use of gigabit Ethernet (GBE) interconnect versus Myrinet in a Linux Xeon cluster. Current status of Solaris x86 porting of LS- DYNA is also ...
Modeling the Nonlinear, Strain Rate Dependent Deformation of Shuttle Leading Edge Materials with Hydrostatic Stress Effects Included
Robert K. Goldberg, Kelly S. Carney - NASA Glenn Research Center
An analysis method based on a deformation (as opposed to damage) approach has been developed to model the strain rate dependent, nonlinear deformation of woven ceramic matrix composites, such as the Reinforced Carbon Carbon (RCC) material used on the leading edges of the Space Shuttle. In the developed model, the differences in the tension and compression deformation behaviors have also been accounted for. State variable ...
Material Modeling of Space Shuttle Leading Edge and External Tank Materials For Use in the Columbia Accident Investigation
Kelly Carney, Matthew Melis - NASA Glenn Research Center
Edwin L. Fasanella - US Army Research Laboratory/VTD
Karen H. Lyle - NASA Langley Research Center
Jonathan Gabrys - Boeing
Upon the commencement of the analytical effort to characterize the impact dynamics and damage of the Space Shuttle Columbia leading edge due to External Tank insulating foam, the necessity of creating analytical descriptions of these materials became evident. To that end, material models were developed of the leading edge thermal protection system, Reinforced Carbon Carbon (RCC), and a low density polyurethane foam, BX-250. Challenges in ...
APPLICATION OF NON-DETERMINISTIC METHODS TO ASSESS MODELLING UNCERTAINTIES FOR REINFORCED CARBON-CARBON DEBRIS IMPACTS
K. Lyle - NASA Langley Research Center, Hampton VA
E. Fasanella - ARL-VTD Langley Research Center, Hampton VA
M. Melis and K. Carney- NASA Glenn Research Center, Cleveland OH
J. Gabrys -The Boeing Company, Philadelphia PA
The Space Shuttle Columbia Accident Investigation Board (CAIB) made several recommendations for improving the NASA Space Shuttle Program. An extensive experimental and analytical program has been developed to address two recommendations related to structural impact analysis. The objective of the present work is to demonstrate the application of probabilistic analysis to assess the effect of uncertainties on debris impacts on Space ...
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