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8th European LS-DYNA Conference

3-Dimensional Forming of Thick Plates - A Comparison of Deep Drawing and an Approach of Rolling and Bending within a Single Process
Manuel Bojahr, Hannes Prommer, Ralf Tschullik, Patrick Kaeding - University of Rostock
A variety of industries require certain 3-dimensional formed thick plates, for example in shipbuilding for shell plates. Nowadays the production of curved ship plates is mainly based on the experience of the worker and is performed manually. The results are good and sufficient for the heretofore use in industry, taking into account that the number of curved plates with the same geometry is quite small. Moreover thick plates with a ...
A constitutive equation for the aging of elastomer and application to dummy impact programs
William W. Feng, John O. Hallquist, Christoph Maurath - Livermore Software Technology Corp
A constitutive equation for chronorheologically simple materials that describes the aging and viscoelastic behaviors of elastomer is presented. A simulated numerical uniaxial relaxation test of a material at various aging stages has been performed. The simulated experimental results demonstrate the chronorheological effect and are used further to determine the material property functions in the constitutive equation. A test of an elastomer ...
A constitutive model for thermoplastics with some applications
Arild Holm Clausen, Mario Polanco-Loria1, Torodd Berstad and Odd Sture Hopperstad - Norwegian University of Science and Technology
A constitutive model for thermoplastics is outlined in this paper. The model consists of two parts: A hyperelastic-viscoplastic response due to intermolecular resistance denoted Part A, and an entropic hyperelastic response due to re-orientation of molecular chains called Part B. Both parts are developed within a framework for finite strains. The main constituents are the Neo-Hookean model describing large elastic deformations, the ...
A modified approach for simulating complex compound structures within early design steps
Georg Gruber, Daniel Klein,Sandro Wartzack - University of Erlangen-Nuremberg
Owing to increasing relevance of lightweight design the deployment of compound structures with their beneficial material characteristics becomes more and more important. These growing demands for lightweight design cannot be met by improving constructive details at the end of the development cycle. On the contrary already the early design steps have to be exploited adequately, since these steps offer the highest freedom of design. The ...
A new advanced visco-elastoplastic eight chain rubber model for LS-DYNA
Dr. Tobias Olsson and Prof. Larsgunnar Nilsson - Engineering Research Nordic AB
A new advanced eight chain rubber model has recently been implemented in LS-DYNA. The material is tailored for polymeric materials. The basic theory is taken from Arruda’s thesis from 1993 but it has been enhanced with advanced features such as the Mullins effect, viscoelasticity, plasticity and viscoplasticity. The Mullins effect is described by two different models: the first one is strain based and developed by Boyce in 2004 and the ...
A New Method for CrachFEM ‘Damage’ Parameter Calculation & Transfer from Autoform to LS-Dyna
Michael Buckley - Jaguar Land Rover
Mike Selig - Autoform Development GmbH
Martin Oehm - MATFEM
 
A novel transversely-isotropic 3D elastic-viscoplastic constitutive law for modeling fiber matrix composites
M. Vogler, R. Rolfes - Leibniz University Hannover
F.X.C. Andrade - University of Porto
J.Schöpfer - Daimler AG
S. Kolling - German Institute for Polymers (DKI)
A transversely isotropic elastic-viscoplastic constitutive law with a novel 3D failure crite- rion is presented, addressing high pressure effects, strain rate sensitivity in yielding and failure and volumetric plastic strain. The constitutive equations are derived in the frame- work of transversely-isotropic invariants, which allow for a coordinate system independent formulation and an easy parameter identification. Triaxiality dependent ...
A pregnant woman model to study injury mechanisms in car crashes
Jérémie Pérès, Michel Behr, Lionel Thollon - IFSTTAR
Kambiz Kayvantash - CADLM
Based on statistical analysis it has been estimated that 3 to 7% of pregnant women experience trauma, 2 third of those trauma are caused by car accidents. According to one epidemiologic study, the frequency of foetal losses could exceed the death frequency of children aged 0 to 4. Some numerical and experimental tools have recently been developed so as to better understand injury mechanisms leading to foetal losses, nevertheless shortcomings ...
About Isogeometric Analysis and the new NURBS-based Finite Elements in LS-DYNA
Stefan Hartmann , David Lorenz - DYNAmore GmbH
David J. Benson - University of California
In the context of isogeometric analysis many research activities have focused on the use of Non- Uniform Rational B-Splines (NURBS). These NURBS-based finite elements have been studied in depth and it has been shown, that they are particularly well suited for computational analysis leading to qualitatively more accurate results in comparison with standard finite elements based on Lagrange polynomials. Due to these motivating results, ...
ALE Incompressible Fluid in LS-DYNA
Nicolas Aquelet - LSTC Livermore
Mhamed Souli - University of Lille
The computation of fluid forces acting on a rigid or deformable structure constitutes a major problem in fluid- structure interaction. However, the majority of numerical tests consists in using two different codes to separately solve pressure of the fluid and structural displacements. In this paper, a monolithic with an ALE formulation approach is used to implicitly calculate the pressure of an incompressible fluid applied to the structure. ...
An airbag application for the ALAR incidences for the Passenger Aircrafts
Vailore Anandan
The airbag system can be designed to reduce the damage on the fuselage during an Approach and Landing Accident Reduction (ALAR) situations as well as ditching in the water for the transcontinental flights. Minimum hull damage protects the passengers in deep waters. A preliminary investigation for this end is performed in this paper. A simple model under 10000 elements is used to investigate the problem. The findings of the LS-DYNA finite ...
An Approach to capture the Ejection Mitigation Requirements of FMVSS 226 with Finite Element Simulations
André Haufe, George Dimitru - DYNAmore GmbH
Andreas Hirth - Daimler AG
Robert Kirchner - Friedmann & Kirchner
 
An Effective Curve Matching Metric for Parameter Identification using Partial Mapping
Katharina Witowski - DYNAmore GmbH
Markus Feucht - Daimler AG
Nielen Stander - Livermore Software Technology Corporation
This paper describes a new method for curve matching essential to the solution of inverse problems represented by system parameter identification. Hysteretic response curves are specifically addressed as a general class. The method is based on Partial Curve Mapping (PCM) of the experiment curve onto the computed curve. This methodology involves a curve matching metric which is computed using the volume between the test curve and the computed ...
An Overview of User Defined Interfaces in LS-DYNA
Tobias Erhart - Dynamore GmbH
The user-defined features in LS-DYNA are powerful tools that allow users in academia or industry to verify research results in the context of general and complicated finite element applications. Implementation work concerns only the special field of interest, and there is no need for the comprehensive task of developing and maintaining the complete finite element software. The most popular user interface is for material modeling. But there ...
Analysis of a single stage compressed gas launcher behaviour : from breech opening to sabot separation
F. Plassard, J. Mespoulet, P. Hereil - Thiot-Ingenierie
Single stage compressed gas guns are used in Shock Physics laboratory to perform characterization experiments and ballistic events. The main advantage of this kind of launcher is that impact conditions are well defined (impact obliquity, impact velocity). In order to achieve high quality in ballistic performance, it is essential to understand the behaviour of the projectile in the barrel of the gun. This paper is devoted to the simulation of ...
Analysis of Fibre Orientation using μCT Data
Sebastian Mönnich, Robert Glöckner , Florian Becker - German Institute for Polymers (DKI)
Integrative simulations are based on a calculated bre orientation from which the local material properties can be derived in several ways. For instance the micro-mechanical model proposed by Tandon and Weng may be used coupled with an orientation averaging approach to include the bre orientation. This approach then gives the elastic properties of the bre matrix compound with a strong dependency, of e.g. the elastic modulus, on the bre ...
Analysis of formability of advanced high strength steel sheets with phenomenologically based failure criteria with separate treatment of instability, shear and normal fracture
K. Isik, C. Soyarslan, A.E. Tekkaya - Technical University of Dortmund
H. Richter - ThyssenKrupp Steel Europe AG
Despite their wide application in sheet metal forming analysis, Forming Limit Diagrams cannot supply reliable results for the cases involving non-proportional strain paths or material classes with reduced ductility such as advanced high strength steels (AHSS). Fracture criteria appear as complimentary tools for assessment of formability in these cases. CrachFEM, as an advanced failure model, merges an instability criterion that includes ...
Application of LS-DYNA SPH Formulation to Model Semi- Solid Metal Casting
F. Pineau, G. D’Amours - National Research Council Canada, Aluminium Technology Centre
Semisolid metal alloys have a special microstructure of globular grains suspended in a liquid metal matrix. This particular physical state of the matter can be exploited to produce near-net-shape parts with improved mechanical properties. Indeed, semi-solid processes take advantage of a much higher apparent viscosity of the die cast materials by limiting the risk of oxide formed on the free surfaces to become incorporated into the casting ...
Behaviour model for semi-crystalline polymer, application to crashworthiness simulations
R.Balieu, F.Lauro, B.Bennani, B.Bourel - Univ Lille Nord de France
K.Nakaya, E.Haran - TOYOTA MOTOR EUROPE
Today polymer materials are frequently used in the transport domain with more severe specification requirements. The behaviour modeling and failure prediction have consequently become a priority. In this paper, an elasto- viscoplastic behaviour model is presented, with non associated plasticity, damage and strain rate effect, which represents the observed behaviours of a semi-crystalline polymer under dynamic loading.
BEM Methods For acoustic and vibroacoustic problems in LS-DYNA
Yun Huang - Livermore Software Technology Corporation
Mhamed Souli - University of Lille
Rongfeng Liu - JSOL Corporation
This paper presents the new developments of finite element methods and boundary element methods for solving vibro-acoustic problems in LS-DYNA. The formulation for a frequency domain finite element method based on Helmholtz equation is described and the solution for an example of a simplified compartment model is presented. For boundary element method, the theory basis is reviewed. A benchmark example of a plate is solved by boundary element ...
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