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7th European LS-DYNA Conference

Determination of Flow Curves by Stack Compression Tests and Inverse Analysis for the Simulation of Hot Forming
B. Hochholdinger, P. Hora - ETH Zurich
H. Grass, A. Lipp - BMW AG
Due to the increasing number of body-in-white parts that are manufactured by hot forming of boron alloyed sheet metal (22MnB5), the demand for a virtual representation of this specific manufac- turing process is evident. For a realistic simulation of hot stamping processes, the accurate modeling of the flow stress as function of strain, strain rate and temperature is essential. In the last years a large varity of ...
An LS-DYNA material model for simulations of hot stamping processes of ultra high strength steels
Dr. Tobias Olsson - Engineering Research Nordic AB
This paper present a new material model (*MAT_244) in LS-DYNA capable of simulating phase transition during quenching and forming. Usually during forming the blank is initially heated to become fully austenitized and then continuously formed and cooled. When the temperature is decreasing the austenite decomposes into different product phases. The amount of each phase does not only depend on the mechanical history, but also on the cooling ...
Modelling the dynamic magneto-thermomechanical behaviour of materials using a multi-phase EOS.
Le Blanc Gaël, Jacques Petit, Pierre-Yves Chanal - Centre d’Etudes de Gramat
L’Eplattenier Pierre - LSTC, Livermore
Avrillaud Gilles - ITHPP
For several years the “Centre d’Etudes de Gramat (CEG)” has been studying the behaviour of materials by means of experimental devices using High Pulsed Powers technologies. Among them, GEPI is a pulsed power generator devoted to ramp wave (quasi isentropic) compression experiment in the 1 GPa to 100 GPa pressure range. It may also produce non shocked high velocity flyer plates in the 0.1 km/s to 10 km/s range of velocity. The basic principle ...
Adjusting the Contact Surface of Forming Tools in Order to Compensate for Elastic Deformations during the Process
Knut Großmann, Hajo Wiemer, Andrè Hardtmann, Lars Penter, Sebastian Kriechenbauer - TU Dresden
Nowadays, despite powerful simulation programs, the tool design process still contains manual and not reproducible work. In specific, the manual die spotting is mostly dependent on the workers experience and consumes a lot of time. A large potential to reduce time and costs is seen by decreasing the die maturing. The paper introduces an approach to obtain deep drawing tools from FE simulation with LS-DYNA, which need less additional manual ...
Improved Tool development Process for novel SCS Technology for Aluminium Sheet Metal
Apostolos Papaioanu, Prof. Dr. Mathias Liewald MBA - Institut für Umformtechnik, Stuttgart
Ralf Schleich - HochschulInstitute Neckarsulm, Neckarsulm
Today’s stretch forming technologies mainly are used for production of large and flat parts made of sheet metal mainly for the aircraft industry (wing fabrication) and for shipbuilding. Because of the high investment costs and high process time, the use of such conventional stretch forming technologies is not qualified for production of car body panels. However, benefits of present stretch forming methods such as improvement of the ...
A PARAMETRIC AND USERFRIENDLY APPROACH TO INCREMENTAL PROCESS SIMULATION OF SHEET METAL FORMING
Dr. Victor Apanovitch, Stefan Huhn - Forming Technologies Inc.
With a steady increase in computational power and decrease in hardware costs during the last few years, the incremental process simulation in the area of sheet metal forming is considered a state-of- the-art tool during the development process at OEMs and many, mainly larger, suppliers. However, the existing pre-processing tools do not support a template based analysis setup that can prevent the need for highly skilled personnel in order to ...
A numerical study of the effect of geometrical factors on bi-layered tube hydroforming
Abed Alaswad, Abdul Ghani Olabi - Dublin City University
Tube hydroforming is one type of unconventional metal forming process in which high fluid pressure and axial feed are used to deform a tube blank in the desired shape. Bi-layered tube hydroforming is suitable to produce bi-layered joints which can be used in special applications such as aerospace, oil production, and nuclear power plants. In this work a finite element study was performed using ANSYS LS-DYNA to investigate the effect ...
Modelling of ductile failure in metal forming
H.H. Wisselink, J. Huetink - Materials Innovation Institute (M2i) / University of Twente
Damage and fracture are important criteria in the design of products and processes. Damage mod- els can be used to predict ductile failure in metal forming processes. Nonlocal models avoid the mesh dependency problems of local damage models. A nonlocal damage model has been implemented in LS- DYNA using the user-subroutines UMAT and UCTRL1. The implemented model will be compared with results obtained with the available option in LS-DYNA to ...
Numerical investigation of draw bending and deep drawing taking into account cross hardening
Clemens Barthel, Till Clausmeyer, Bob, Svendsen - University of Technology,Dortmund, Germany
Sheet metal forming is one of the most important manufacturing processes. Computer simulation has become the tool for modeling such processes and also for predicting the springback in the final part. The talk will deal with two different metal forming processes, namely draw bending and deep drawing of a cup. In the draw bending case a metal strip is clamped into a testing device in such a way that it is bent over a roller. The strip is then ...
Identification of an advanced hardening model for single phase steels
Muhammad Noman, Bob Svendsen - University of Dortmund
Sheet metal forming processes cover a wide range of applications in industry. In order to model sheet metal forming processes using numerical simulation an accurate description of the material behavior is required. To this end a material model has been implemented which is capable of capturing the move- ment and proportional expansion of the yield surface along with the change in the shape of the yield surface. The former is described as ...
Forming limit diagrams with an FE-based approach for sheets under non-proportional loading
A. Reyes, O. S. Hopperstad - Norwegian University of Science and Technology
T. Berstad, O.-G. Lademo - Norwegian University of Science and Technology/ SINTEF Materials and Chemistry
In this study, LS-DYNA was used to predict the experimental forming limit diagrams (FLDs) for pre- strained sheets in aluminum alloy Al2008-T4 found by Graf and Hosford [1]. The original data of Graf and Hosford [1] includes numerous pre-straining situations, but it was here chosen only to investigate pre-straining by biaxial and uniaxial tension. In order to generate the FLDs, several analyses of a square patch were run systematically to ...
A Systematic Approach to Model Metals, Compact Polymers and Structural Foams in Crash Simulations with a Modular User Material
G. Oberhofer, H. Gese - MATFEM Partnerschaft Dr. Gese & Oberhofer
A. Bach, M. Franzen, H. Lanzerath - Ford Research & Advanced Engineering Europe
Today the automotive industry is faced with the demand to build light fuel-efficient vehicles while optimizing its crashworthiness and stiffness. A wide variety of new metallic and polymeric materials have been introduced to account for these increased requirements. Numerical analysis can significantly support this process if the analysis is really predictive. Within the numerical model a correct characterization of the material behaviour – ...
Micromechanics analysis applied to the modelling of aluminium honeycomb and EPS foam composites
Gaetano Caserta, Lorenzo Iannucci - Imperial College London
Ugo Galvanetto - Padova University
A 3D Finite Element model of an innovative composite material, configured as a layer of expanded aluminium honeycomb placed on top of a layer of expanded polystyrene foam, has been developed and validated against experimental data obtained from quasi-static tests. Ls-Prepost was used to generate the model. Ls-Dyna was used to simulate the behaviour of this material under compressive loads. The objective was to reproduce deformation ...
Multi-Scale Modeling of Crash & Failure of Reinforced Plastics Parts with DIGIMAT to LS-DYNA interface
L. Adam, A. Depouhon, R. Assaker - e-Xstream engineering
This paper deals with the prediction of the overall behavior of polymer matrix composites and structures, based on mean-field homogenization. We present the basis of the mean-field homogenization incremental formulation and illustrate the method through the analysis of the impact properties of fiber reinforced structures. The present formulation is part of the DIGIMAT [1] software, and its interface to LS-DYNA, enabling multi-scale FE ...
Numerical simulation of low-velocity impact loading of polymeric materials
H. Daiyan, F. Grytten, E. Andreassen, R.H. Gaarder, E.L. Hinrichsen - SINTEF Materials and Chemistry
O.V. Lyngstad - Plastal AS
H. Osnes - University of Oslo / Simula Research Laboratory
Simulation of ductile polymers subjected to impact loading has become an important topic [1, 2], especially for automotive components related to passenger and pedestrian safety. The aim of our work is to establish and validate numerical models for impact response, and this presentation will focus on a study of impact on injection molded polypropylene plates. SAMP-1 (Semi-Analytical Model for Polymers) [3] was selected as constitutive model ...
A constitutive model for thermoplastics intended for structural applications
Mario Polanco-Loria, Torodd Berstad - SINTEF Materials and Chemistry / Structural Impact Laboratory (SIMLab)
Arild Holm Clausen, Odd Sture Hopperstad - Department of Structural Engineering, NTNU/Structural Impact Laboratory (SIMLab)
This paper presents a hyperelastic-viscoplastic constitutive model for thermoplastics [1]. It is partly based on a model proposed by Boyce et al. [2]. The model involves a hyperelastic- viscoplastic response due to intermolecular resistance, and an entropic hyperelastic response due to re-orientation of molecular chains. A Neo-Hookean material model is selected for describing large elastic deformations. Moreover, the Raghava plastic yield ...
Selecting Material Models for the Simulation of Foams in LS-DYNA
Brian Croop,Hubert Lobo - DatapointLabs
Foams are multi-phase materials that exhibit dramatically different properties that depend on the matrix material as well as the pore microstructure. This additional degree of freedom from the presence of the gas phase makes material modelling for foams a difficult matter. LS-DYNA offers a variety of material models, each with capabilities designed to capture the unique behaviour of a different types of foam. The selection of the correct ...
Simulation of Dynamic Delamination and Mode IEnergy Dissipation
Muhammad Ilyas, Christine Espinosa, Frédéric Lachaud, Michel Salaün - Université de Toulouse
Delamination initiation and propagation of aeronautic composites is an active field of research. In this paper we present a methodology for critical energy release rate correlation of numerical simulation and experimental data. Experiments of mode I critical energy release rate were carried out at quasi static and pseudo dynamic loading rates. Cohesive finite elements are used to predict the propagation of delamination in a carbon fiber and ...
A Study of Material and Architectural Effects on the Impact Response of 2D and 3D Dry Textile Composites using LS-DYNA
Gaurav Nilakantan, Michael Keefe, John W. Gillespie Jr. - University of Delaware
Travis A. Bogetti, Rob Adkinson - US Army Research Laboratory
High strength 2D fabrics and 3D textile composites comprised of materials such as KevlarTM, VectranTM, ZylonTM, and S2-Glass® find applications in protective systems such as personnel armor, spall liners, and turbine fragment containment. Various parameters can significantly affect the response of these fabrics under high rate impact including yarn/tow geometry (cross section), yarn/tow material (modulus, strength), and architecture ...
Taking into Account Glass Fibre Reinforcement in Polymer Materials: the Non Linear Description of Anisotropic Composites via the DIGIMAT to LS-DYNA Interface
Dr. Jan Seyfarth, Dr.-Ing. Matthias Hörmann - CADFEM GmbH
Dr.-Ing. Roger Assaker - e-Xstream Engineering
Chandra S. Kattamuri, Bastian Grass - BSH Bosch und Siemens Hausgeräte GmbH
In the context of light weight construction the replacement of metal parts with substitutes made from plastic plays a major role. These devices commonly are manufactured through injection moulding and reinforced by different amounts of glass fibres to enhance the strength of the material. In everyday application this poses a challenge to the engineer as due to this processing the local orientation of the reinforcements is varied on a broad ...
Progressive Damage Modeling of Plain-Weave Composites using LS-Dyna Composite Damage Model MAT162
Dr. Bazle A. Gama, Prof. John W. Gillespie Jr. - University of Delaware
Dr. Travis A. Bogetti - US Army Research Laboratory
Progressive damage of plain weave S-2 Glass/SC15 composites under in-plane tension, compression, and shear, through-thickness tension and compression, and transverse interlaminar and punch shear loading is presented for a unit single element using the MAT162 composite damage model in LS- Dyna. While the detail formulation of the MAT162 material model can be found in the Keyword user's manual [1], the main objective of this paper is to ...
Study of the Behavior of Dummy Hybrid III Upper Extremities
Sascha Kutschenreuter, Maxime Dagonet - Takata Petri AG
Studies of crash simulations resulted in the assumption that an interaction of the upper occupant extremities with the vehicle interior has effects on the occupant loadings, e.g. the chest acceleration. Quantifying this effect requires a dummy model also valid for the area of upper extremities. A suitable test procedure shall help to identify possible force paths via the arms into the dummy torso and, as a ...
Numerical Investigations to Determine Sources for the Scatter of the BioRID Dummy
S. Stahlschmidt - DYNAmore GmbH
A. Hirth - Daimler AG
The BioRID v2.5 model is in a very fine validation state until now. In some new tests for further validation of the model, one can observe a very strong scatter in some major signals of the tests. Some of these signals are used to calculate injury criteria which are used to determine the quality of a seat in rear crash scenarios in consumer tests. This paper describes the new validation test setup and gives an overview about the latest ...
Developments in Finite Element Safety Models
J. Rasico - FTSS
FTSS has been providing Finite Element models to the safety community for over a decade. This has resulted in an expansive family of; commonly used Anthropomorphic Test Devices (ATDs), dummies primed for future regulation, and complimentary safety tools for the examination of unique protection systems, such as ejection mitigation. In conjunction, the last 10 years have seen a continuous demand for increased quality and functionality of ...
Development of the PDB WorldSID 50th Model with the German Automotive Industry
A. Gromer, S. Stahlschmidt, R. D'Souza - DYNAmore
In times where simulation methods are well-established in Vehicle Passive Safety Development, it is indispensable to provide a virtual equivalent of current hardware dummies. Thus, German car manufacturers decided to build up a WSID50th finite element model. Due to the experience of former FAT dummy development projects, the processing of the WSID50th model achieves a high efficiency level. The project started with building up a model using ...
Head injury prediction tool for protective systems optimisation
Deck Caroline, Willinger Rémy - Strasbourg University
This paper presents an original numerical human head FE models followed by its modal and temporal validation against human head vibration analysis in vivo and cadaver impact tests from the literature. The human head FE model developed presents two particularities : one at the brain-skull interface level were fluid-structure interaction is taken into account, the other at the skull modelling level by integrating the bone fracture simulation. ...
MATERIAL MODELING OF ORTHOPEDIC INSOLES
S. Kolling, M. Neubert - Giessen University of Applied Sciences
J. Subke, J. Griesemann - Biomechanics Lab
An experimental setup is presented for the material characterization of rubber-like sensomotoric insoles. This setup consists of local hardness measurements, quasi-static compression tests and dynamic testing using the 4a Impetus II pendulum test system [1]. A correlation between the measure of shore hardness and the stress strain relation of rubber-like materials is presented and verified in order to consider the inhomogeneous properties of ...
Development of numerical models for the investigation of motorcyclists accidents
Mazdak Ghajari, Lorenzo Iannucci - Imperial College London
Caroline Deck, Remy Willinger - Strasbourg University
Ugo Galvanetto - Padova University
The Finite Element (FE) method was employed to develop and enhance numerical models that can be used for simulating accidents involving motorcyclists. They are the FE models of a commercial helmet, the human head and the Hybrid III dummy. The composite shell and foam liner of the helmet, which are the most important components in terms of energy absorption, were generated using the Ls-Dyna preprocessing software. The FE model of the human ...
Improvements and Validation of an Existing LS-DYNA Model of the Knee-Thigh-Hip of a 50th Percentile Male Including Muscles and Ligaments
Dr. Chiara Silvestri, Mario Mongiardini, Prof. Dr. Malcolm H. Ray - Worcester Polytechnic Institute
A detailed review of an existing LSDYNA finite element (FE) model of the Knee-Thigh-Hip (KTH) of a 50th percentile male was accomplished. The main scope was to refine some aspects of the model for obtaining a more appropriate and biofidelic tool for injury mechanics investigation of the KTH in frontal car crashes. Detailed reviews of this model were performed with regards to material properties of the bone models used for representation of ...
New Method to Characterize Airbag Inflators On the Way to OoP Simulation
Juan Fernández - Takata-Petri AG
An accurate Out-of-Position (OoP) simulation will be a mile stone for the development of restraint systems, as this would save hundreds of expensive hardware tests. OoP load cases are currently required by the US legislation and as in-house specification by many car manufactures for other markets. But simulating OoP is a difficult issue, as several challenges have to be addressed, for example: An improved dummy model validated against new ...
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