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Corpuscular method for airbag deployment simulations
Lars Olovsson, IMPETUSAfea AB
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MATHEMATICAL MODELLING OF THE EARLY PHASE DEPLOYMENT OF A PASSENGER AIRBAG – FOLDING USING ORIGAMI THEORY AND INFLATION USING LS-DYNA PARTICLE METHOD
Krystoffer Mroz, Bengt Pipkorn - Autoliv Development AB, Sweden
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Initial evaluation of the particle method for mathematical out-of-position simulations was performed. The evaluation was carried out by means of static inflation and impactor tests. In the out-of-position load case, the occupant is initially positioned very close to airbag module and the interaction airbag-occupant occurs during the early deployment phase of the airbag. Thus a realistic representation of the folding pattern together with an ...
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Concept Design of an A-Pillar Mounted Airbag for Pedestrian Head Protection
Jianfeng Yao, Jikuang Yang - Chalmers University of Technology
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Accident investigations have shown that in pedestrian-versus-vehicle accidents, windshield edges, A-pillars, cowls are the main sources for severe head injuries due to their high stiffness. To mitigate head injury severities, it is necessary to improve the safety performance of these structures. An A-pillar mounted airbag system (AMAS) was devised with the aim to prevent head from directly impacting against stiff structures such as A-pillars, ...
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FE-MODELLING OF HYDRODYNAMIC HULL-WATER IMPACT LOADS
Ivan Stenius, Anders Rosén - KTH Centre for Naval Architecture
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This paper considers finite element modelling of the hydrodynamic loads in hull-water impacts. The commercial FE-code LS-DYNA is used with a multi-material arbitrary Lagrangian-Eulerian formulation and a penalty contact algorithm. The great advantage of this modelling technique is that it enables the modelling of the instantaneous fluidstructure interaction. A difficulty is however the selection of appropriate modelling parameters. A method to ...
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WATER IMPACT: EXPERIMENTAL TESTS AND NUMERICAL SIMULATIONS USING MESHLESS METHODS
Marco Anghileri, Luigi Castelletti, Edoardo Francesconi - Politecnico di Milano, Italia
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The outcomes of a research focusing on water modelling and fluid-structure interaction, are here presented. A number of water impact drop tests using a typical aircraft skin panel were performed. The tests were numerically reproduced modelling the fluid region using the two meshless methods implemented in LSTC/LS-Dyna 971: the Smoothed Particle Hydrodynamics and the Element Free Galerkin method. The accuracy of the models was evaluated referring ...
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HIGH VELOCITY IMPACTS SIMULATIONS WITH SPH METHODS IN LS-DYNA
Gilles Mazars, Gabriel Desille, Vincent Lapoujade - CRIL Technology - Groupe ALYOTECH
Christian Durin - CNES
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Several high velocity impacts (HVI) can be simulated using the SPH method in LSDYNA. Space debris, whose quantity is on the rise, now pose a major threat to satellites. Effective impact models enable both the development of more efficient protections and the prediction of the damage that an individual HVI will cause to structures. This paper aims to provide advice and words of caution on how to best model such impacts but also presents an ...
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Investigation into the rising air pressure inside the door during side impacts
Michael Machens - Wilhelm Karmann GmbH
Thomas Wessels - FH Osnabrück
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A crucial point in side impacts is the rapid intrusion of the side structure of the door into the passenger compartment. In the initial stage of the crash it is essential to provide sufficient space between occupant and door trim to enable a proper unfolding of the side airbag. This problem can be alleviated by using the rising air pressure inside the door as an additional input for crash sensing. When combined with the common acceleration ...
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SIMULATION OF THE IMPACT ON GROUND OF AIRDROP LOADS TO DEFINE A STANDARD WORST CASE TEST
Yves de Lassat de Pressigny, Thierry Baylot - Centre d’Essais en Vol, Ministère de la Défense, France
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The French Flight Test Centre in Toulouse (CEV Tl) made in 2004 prototype simulations of ground impact after airdrop (2d-40, 5th European LS-DYNA users conferences.) Its purpose was to enable the test centre to achieve parametric analyses of the shock level produced by airdrop with a combination of simulation and real tests, which was not feasible with tests only (because of the number of test cases required). Indeed a first proposal with ...
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Fan Blade Bird Strike Analysis Using Lagrangian, SPH and ALE Approaches
Alexander A. Ryabov, Vladimir I. Romanov, Sergey S. Kukanov - Sarov Engineering Center
Yuriy N. Shmotin, Pavel V. Chupin - NPO Saturn
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Fan blade bird resistance is one of the most important certification requirements for modern jet engines. The development test to meet the requirement is difficult and costly experiment. The expenses can be significantly reduced by using the numerical simulation of fan blade bird strike problem in the design of jet engine. The common technique for such simulations is modeling of bird as a solid cylinder or ellipsoid with material properties ...
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EVOLVING TECHNOLOGY: MULTI-PHASE, MULTIMATERIAL, ALE APPROACH AND TOOL DEVELOPMENT FOR BURIED BLAST SIMULATION
Dr. Rahul Gupta - U.S. Army Research Laboratory Aberdeen Proving Ground
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Modeling the response of structures subjected to blast from shallow buried explosives poses a challenge, primarily due to the inherent coupled interaction. The response of the structure affects the surrounding blast pressure field, which in turn, affects the loading on the structure; therefore the problem is coupled in nature. The problem is complicated due to the difference in time scales associated with the blast loading and structural damage. ...
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Increasing Initial Internal Energy of Air Elements near Explosive for Fluid-Structure Models of a Steel Plate Subjected to Non-contact Explosion
Wen-Chih Li, Wen-Feng Yu, Ding-Shing Cheng - National Defense University
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This study was to simulate a steel plate subjected to non-contact explosion by using Arbitrary Lagrangian-Eulerian (ALE) algorithm of the LS-DYNA software. A 3-D Fluid-Structure interaction model was considered. The numerical result would be compared with S.D. Boyd’s experiment, which 250g Pentolite explosive detonated above a 5 mm thick steel plate. The Eulerian mesh for explosive and air and the Lagrangian mesh for steel plate and its ...
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MPP DECOMPOSITION OF A SPH MODEL
Jean Luc Lacome - LSTC Vincent Lapoujade Cril Technology – Groupe Alyotech
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SPH, Smoothed Particle Hydrodynamics, is a very efficient tool to model industrial problems where large deformations occur. However, one disadvantage of the SPH technique is the expensive cpu cost compared to standard Finite Elements. Using the MPP version of LS-DYNA allows users to handle large problems (more than a million of particles) in a reasonable time. Due to the meshfree nature of the SPH method, standard decompositions used for finite ...
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Fluid Structure Interaction for Immersed Bodies
Jason Wang, Hao Chen - Livermore Software Technology Corporation
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A new method for automatically constructing the coupling surface along shell edges is developed. By using this new "edge" option together with "shell thickness" option in the *CONSTRAINED_LAGRANGE_IN_SOLID card, we can accurately model problems involving shell structures with leading edges cutting into ALE materials. Engineering problems include bird striking at propulsion system fan blades; helicopter impacting water. This new feature is ...
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ALE Modeling of Surface Waves
AQUELET Nicolas - Livermore Software Technology Corporation
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An Arbitrary Lagrange Euler formulation for the propagation of surface waves is developed in LS-DYNA®. The ALE computational time step in this code is divided in two cycles: a Lagrangian cycle in which the mesh follows the material deformation and an advection cycle in which the users through remapping algorithms control the mesh motion. The new feature presented in this paper is one of these remapping algorithms. It enables a Lagrangian ...
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Advanced Finite Element Model for AE-MDB Side Impact Barrier
M. Asadi , P. Tattersall - Cellbond Composites Ltd.
B. Walker - ARUP Campus (UK)
H. Shirvani - Anglia Ruskin University (UK)
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This paper represents a new Finite Element simulation model for AE-MDB v3.9 side impact barrier and proposes a method on creating suitable assumptions and material data. Cellbond AE-MDB barrier investigation was carried out to produce an advanced FE model. Experimental Flat Wall and Offset Pole test results were used to validate the accuracy of the developed models. The explicit LS Dyna 3D code was used to model the geometries, and the Material ...
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Application of Shell Honeycomb Model to IIHS MDB Model
Shigeki Kojima - TOYOTA TECHNICAL DEVELOPMENT CORPORATION
Tsuyoshi Yasuki, Koji Oono - Toyota Motor Corporation
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This paper describes a new finite element modeling method of Aluminum honeycomb using shell elements. It is our new modeling method that cell size of honeycomb structure is enlarged to increase time step size for FEM analysis, and compressive strength is controlled by thickness of shell elements. New modeling method was applied to IIHS moving deformable barrier model, and side impact analysis with a full vehicle model was performed. The result ...
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Contact and Sliding Simulation of Rubber Disk on Rigid Surface with Microscopic Roughness
Sunao Tokura - JRI Solutions, Ltd.
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It is crucial to obtain detailed information about frictional interaction between tire and road surface to estimate performance of vehicle brake system or tire on real road surface. Simulation using Finite Element Method (FEM) in addition to experimental procedure is regarded to be useful to investigate contact behavior between tire and road surface. However, indeed, it is difficult to apply FEM simulation for such a problem since contact and ...
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Development of validated Finite element model of an articulated truck suitable to simulate collisions against road safety barriers
M. Pernetti - Second University of Naples
S. Scalera, G. Cibllis - University of Naples "Federico II"
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Crashworthiness is one of the most important aspect which is taken into account in road design. The effectiveness of Finite Element Method (FEM) to solve major design problems and as a tool to perform parametric studies, has been plainly demonstrated in literature. Of course this is possible only when available models of vehicles and devices are calibrated in a wide range of impact conditions. This research, was intended to develop a well ...
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Development of validated Finite element model of a rigid truck suitable to simulate collisions against road safety barriers
M. Pernetti - Second University of Naples
S. Scalera - University of Naples "Federico II"
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The effectiveness of FEM (Finite Element Method) to improve the crashworthiness, both of the vehicle and of the road safety hardware, has been plainly demonstrated in literature. As well known, such a methodology can be successfully employed (i) as a support to design novel devices and (ii) as a tool to perform parametric studies to assess the influence of different factors. Of course this is possible only when available models are calibrated in ...
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Evaluation of rail height effects on the safety performance of W-Beam barriers
Dhafer Marzougui, Pradeep Mohan, Cing-Dao (Steve) Kan - The George Washington University, USA
Kenneth Opiela - US Department of Transportation, USA
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The objective of this study is to investigate the effect of rail height on the safety performance of G4(1S) w-beam guardrail systems. The study involved three steps. In the first step, a detailed finite element model of the G4(1S) guardrail system was created. The model incorporated the details of the rail, connections, the post, the blockout, and the soil in which the post was embedded. To validate the model of the wbeam guardrail system, a ...
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FE-MODELING OF SPOTWELDS AND ADHESIVE JOINING FOR CRASHWORTHINESS ANALYSIS
A. Haufe , G. Pietsch - Dynamore GmbH, Germany
M. Feucht, S. Kolling - DaimlerChrysler AG, Germany
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The increasing demands with regard to the predictive capabilities and the exactness of
crash simulations require more and more investigations into numerical models in order
to capture the physical behavior reliably. Steps towards this goal are the usage of finer
meshes which allow for a better geometrical representation and more sophisticated
material models which allow better prediction of failure scenarios. Another important
playground ...
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Model improvement during seat project
Christofer Karlsson, Scania CV AB
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To help predict the behaviour of a seat assembly when performing a seat belt anchorage pull test (according to regulation ECE R14/05 and directive 76/115/EEC) a FE-model has been built and improved in several steps. To increase the accuracy of the simulation (quasi static), a number of modifications were made to the initial model. The adjustments include higher mesh density, allowing a better representation of the geometry. A tensile strength ...
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OPTIMIZATION OF DESIGN PARAMETERS FOR A CONTACT SENSOR IN BUMPER-PEDESTRIAN IMPACT BY USING FE MODELS
Sunan HUANG, Jikuang YANG - Chalmers University of Technology, Sweden
Rikard FREDRIKSSON, Autoliv Research, Autoliv AB, Sweden
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An active hood system was developed in Autoliv to minimize the head injury risk of pedestrians from impacts with car front. In order to detect the car-to-pedestrian impact in time, a contact sensor placed in the car bumper is needed. The stiffness of the bumper foam material is highly dependent on the environment temperature, which will result in unstable output from the contact sensor. A new pedestrian-bumper contact sensor was developed in ...
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Road Safety Devices Assessment for Sliding Motorcyclists Protection
M. Anghileri, L. Castelletti, A. Milanese, M. Pirola, F. Pistochini - Politecnico di Milano, Italia
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Statistics show that the impact with a roadside safety barrier of a motorcyclist sliding on the pavement after an accident is potentially more dangerous than the accident itself. In recent years, in effort to avoid the most serious consequences, the approach to barriers design changed and specific devices have been introduced to improve motorcyclists’ safety. At LAST Crash Labs, the effectiveness of one of these devices was experimentally and ...
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Rupture Modeling of Spot Welds Suitable for Crash FE Analysis in Vehicle Development Process
Koushi Kumagai, Masakazu Shirooka, Jirou Ohachi, Toshirou Ogawa - Toyota Motor Corporation
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This paper describes the development of rupture modeling of spot welds suitable for crash FE analysis in vehicle development process. The authors presented a detailed spot weld rupture model called ‘spider web model’ in Toyota and confirmed that it closely correlates with actual full vehicle crash test results. Although, the spider web model is accurate, extensive effort is required to construct the model. Also, the spider web model can only ...
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Simulation of a CMVSS 215 bumper pendulum test series with LS-DYNA
Armin Huß, Heiko Beck, Ingenieurbüro Huß & Feickert, Germany
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In the course of an increasing automotive development for international markets many new loadcases have to be tested. The Canadian bumper pendulum test (CMVSS215) is one of these loadcases that form a special challenge for the simulation with LS-DYNA due to its sequential process. For this test four different bumper pendulums have to impact the vehicle, while with each new test the prior damages have to be taken over. Until now the simulation ...
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Virtual Modelling of Motorcycle Safety Helmets: Practical Problems
Alessandro Cernicchi, Ugo Galvanetto, Lorenzo Iannucci - Imperial College London
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Motorcycle helmets are safety devices that can be optimised to perform better in different impact configurations. It is not easy to determine the mechanical properties of a particular model of helmet which maximise its effectiveness in real impact conditions and it is not surprising that most helmet producers use empirical design procedures and assess the effectiveness of their products by carrying out numerous experimental impact tests. The ...
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STRUCTURAL OPTIMIZATION OF PRODUCT FAMILIES EXPOSED TO CRASH LOADING
Michael Öman - Linköping University, Sweden
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This paper discusses the problem of structural optimization in product family design and different methodologies are evaluated for weight optimization of components that are common for members in the family. First, the benefits of product family design are presented, followed by a discussion of the complexity of the design problem when the product family is exposed to crash loading and multiple load cases. It is concluded that in large problems ...
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USING LS-OPT/LS-DYNA IN A MULTI-ATTRIBUTE OPTIMIZATON
Forsberg Jimmy, Björkman Gunnar - VTEC
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This paper summarizes the experiences of using the LSTC environment in a multiattribute optimization. The work was carried out in an on-going project, SuperLIGHTCar (SLC), which aims to reduce the weight of the body in white (BIW) of a compact class car by at least 30%. This objective is made possible by using new materials and a blend of materials in the design. The car should still fulfil user rating, e.g. Euro NCAP demands but also demands of ...
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VOLVO TECHNOLOGY VEHICLE STRUCTURAL OPTIMIZATION ENVIRONMENT
Gunnar Björkman,Jimmy Forsberg - Volvo Technology
Jan Engström - SCH Incubator AB
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With the ever increasing capability in computer power, optimizing a full vehicle structure including most of the crash load cases will be a real possibility in the near future. For example, the Cell chip used in PS3 or the availability of recent GPU of high end PC graphics cards delivers 100 – 1000 GFLOPS. The bottleneck in this scenario will not be the computer power, instead the problem will be how to feed the computers with models and input ...
