7th European LS-DYNA Conference

Recent Developments in LS-DYNA: In this presentation Dr. John O. Hallquist, founder and president of Livermore Software Technology Corporation (LSTC), will give an overview about recent developments in LS-DYNA. LS-DYNA is a highly advanced general-purpose nonlinear finite element program that is capable of simulating complex real world problems. The distributed memory solver provides very short turnaround times on Unix, Linux and Windows clusters. The major development ...
http://www.dynalook.com/european-conf-2009/A-I-01.pdf
Wood and wood products - linking multiscale analysis and structural numerical simulations: Wood is one of the oldest construction materials known to man. Over thousands of years it has been mainly used in a craft framework, so that current design rules are often based on experience and tradition. The scientific knowledge about the material behavior is often surprisingly poor. In order to exploit the extraordinary ecological potential of the material and to enable its structural use also in an industrial framework, improved ...
http://www.dynalook.com/european-conf-2009/A-I-02.pdf
Virtual engineering and planning process in sheet metal forming: Nowadays the engineering and planning process in sheet metal forming is fundamentally supported by CAD and CAE systems. Beside the full 3D design process of parts and tools the simulation of sheet metal forming processes has established itself in the last 15 years within standard industrial practises. Nevertheless the virtual engineering and planning consists of more than just CAD and CAE tools. For a coordinated and effective process it is ...
http://www.dynalook.com/european-conf-2009/A-I-04.pdf
From 6 months to 6 weeks "Multi Disciplinary Optimisation MDO": The traditional new-vehicle design cycle is very time consuming due to the sequential approach used. The need to reduce time to market for new vehicles as well as the increased affordability of high- performance computing, which can process hundreds of simulations concurrently, has led to the increased adoption of MDO processes. The goal of an MDO is to provide a more consistent, formalized process for complex system design than that found ...
http://www.dynalook.com/european-conf-2009/A-I-06.pdf
LS-DYNA used to analyze the drawing of precision tubes: Long precision tubes are commonly made using the floating plug tube drawing process. The process has been analyzed using various methods e.g. upper bound method and FEM [1-10]. The die land and the plug land are usually cylindrical and form a cylindrical bearing channel between the die land and the plug land. The influence from the length of the bearing channel on the drawing force has only been dealt with in very few papers. In [2] it is ...
http://www.dynalook.com/european-conf-2009/A-II-02.pdf
High Speed Impact - Test and Simulation: Deformation processes of structures under dynamic loading have been investigated both experimentally and by simulation for many years now. Various rate dependencies in many materials, wave and shock wave phenomena as well as material tests for their quantitative description have been identified. In parallel, mathematical formulations for the observed material behavior and numerical schemes for time dependent approximations of the governing ...
http://www.dynalook.com/european-conf-2009/A-II-04.pdf
Reliability-based Multi-Objective Optimization and Visualization using LS-OPT Version 4: This study expounds the multi-objective optimization of a realistic crashworthiness problem with special reference to the incorporation of uncertainty and the visualization of the Pareto Optimal Frontier (POF). LS-OPT® and LS-DYNA® are used for the optimization based on the C2500 truck model developed by NHTSA. The design problem is set up as a Reliability-Based Design Optimization (RBDO) problem which includes specifications for the ...
http://www.dynalook.com/european-conf-2009/A-II-05.pdf
New Features of LS-PrePost 3.0: The introduction of the new LS-PrePost 3.0 will be presented here. A completely redesigned graphical user interface has been implemented in the new version of LS-PrePost 3.0. Tool bars and icons are being used for the main manual system to replace the old text based button system. The icons can be set to have text or without text. The new interface provides the maximum possible graphical area for the model rendering at the same time allow ...
http://www.dynalook.com/european-conf-2009/A-II-06.pdf
Crash Simulation of an F1 Racing Car Front Impact Structure: Formula 1 motorsport is a platform for maximum race car driving performance resulting from high-tech developments in the area of lightweight materials and aerodynamic design. In order to ensure the driver’s safety in case of high-speed crashes, special impact structures are designed to absorb the race car’s kinetic energy and limit the decelerations acting on the human body. These energy absorbing structures are made of laminated composite ...
http://www.dynalook.com/european-conf-2009/B-I-02.pdf
Dynamic Simulation of Mechatronic Systems: A growing number of safety systems are implemented in modern vehicles. Thereby vehicles become more complex and in succession the quantity of potential error causes is increasing. Numerical simulation and prototype tests are used to investigate vehicle behaviour and prevent aberrations at an early stage. However, prototype tests on full vehicle level are not feasible in early development stages. Numerical simulation is an effective tool ...
http://www.dynalook.com/european-conf-2009/B-I-03.pdf
Improving Analysis Accuracy By Modeling rivets/bolts As Solids In Sheet Metal Structure: In general, main assembly consists of different sub-assemblies. These sub-assemblies are joined together using rivets/bolts, welds etc. Individual subassembly is often verified for performance using commercial CAE software. To save time, rivet/bolt joints are usually modeled with beam-spider arrangement. Spider represents the rivet/bolt head and a beam connecting two spiders at the centre represents the rivet/bolt diameter. Analyst’s always ...
http://www.dynalook.com/european-conf-2009/B-II-02.pdf
Combined Numerical/Experimental Approach for Rivet Strength Assessment: The failure mechanism of common aeronautical structures is influenced by the crash behaviour of the riveted joints. Therefore, crashworthiness analyses of aeronautical structures require accurate models of the joints under crash conditions for a correct prediction of the crash behaviour of the structure. In this work, a method to create reliable FE models able to reproduce the behaviour of rivets under crash conditions is introduced. Using ...
http://www.dynalook.com/european-conf-2009/B-II-03.pdf
Characterisation and Simulation of Structural Adhesives: The analysis of adhesive bonded joints and structures relies on accurate materials data and mathematical models. In the present study the goal was to develop a method for simulating accurately, using LS-Dyna, the behaviour of aluminium structures bonded with a single part, heat curing epoxy adhesive. This required a structure with known boundary conditions and for which the substrates deformed in a predictable manner. A suitable specimen, ...
http://www.dynalook.com/european-conf-2009/B-II-04.pdf
Investigation of Accuracy Improvement on Crashworthiness Simulation with Pre-Simulation of Metal Forming.: To improve the accuracy of crashworthiness simulation, it is preferable to consider the effects of metal forming. However, this approach was difficult in practice since analyzing the stamping simulation in detail requires much work. This paper describes the influence of residual strain, work hardening and material thickness changes resulting from the stamping process on the crashworthiness simulation. In almost all impact load cases, the ...
http://www.dynalook.com/european-conf-2009/B-III-01.pdf
Considering damage history in crashworthiness simulations: Crashworthiness simulations using explicit Finite Element methods are a central part of the CAE process chain of car body development. Since crash tests of prototype cars at an early development stage are very expensive, a maximum in predictive performance of crash simulations can make a substantial contribution to a cost-efficient car development process. A central issue to ensure this, is an accurate prediction of ...
http://www.dynalook.com/european-conf-2009/B-III-02.pdf
COUPLED FEM CALCULATIONS - A CAE TOOL TO IMPROVE CRASH-RELEVANT AUTOMOTIVE BODY COMPONENTS BY LOCAL HARDENING: In the automotive industry, there is an increasing demand for weight reduction as well as safety requirements. These demands have motivated the use of locally optimized components. This study shows how local rigidity of crash-relevant side rails made of multi-phase steels can be improved by local hardening and thus avoiding an increase of the cross section. At the same time simulation process chains were completed and results validated by ...
http://www.dynalook.com/european-conf-2009/B-III-03.pdf
Damage modelling of a TRIP steel for integrated simulation from deep drawing to crash: The local mechanical properties e.g. flow stress and fracture strain in an automotive component manufactured by deep drawing are inhomogeneous due to different local deformation degrees which affect the component behaviour under crash loading. A reasonable approach for modelling the damage behaviour of a component produced by deep drawing is a coupling between forming simulation and crash simulation. The open questions are which material ...
http://www.dynalook.com/european-conf-2009/B-III-04.pdf
An assessment of the new LS-DYNA layered solid element: basics, patch simulation and its potential for thick composite structure analysis: One major component of fuel cell vehicles is the hydrogen storage system. A promising and nowadays mostly used approach is to store hydrogen in wet wound carbon fiber reinforced plastic (CFRP) vessels manufactured by filament winding process with an operating pressure of up to 70 MPa (hereafter referred as H2 vessel). Due to the inherent complexity and 3-dimensional nature, accurate behavior of such thick composite structures in impact ...
http://www.dynalook.com/european-conf-2009/B-IV-01.pdf
Quicker Process to Consider Strain Hardening for Crash Analysis Using HYCRASH: As one of the important issues in correlation of crash analysis, we know that the press-forming effect has large influence for the result of the analysis. Some tries and studies were carried out to assume the forming result to the crash analysis. However these actions haven’t spread to the actual product development because of some difficulties. We mark the Inverse Solver to solve this issue and have developed the new solver HYCRASH, ...
http://www.dynalook.com/european-conf-2009/B-IV-03.pdf
An Investigation to Compare the Application of Shell and Solid Element Honeycomb Model in ODB: Cellbond and ARUP have launched their advanced crash barrier models in 2006 and since the time a continuous study has been carried out to distinguish costumer requirements and review feedbacks. Existing barrier models are constructed using the solid element configuration in honeycomb segments along with validated Modified_Honeycomb material cards. Due to a number of demands on using Shell based honeycomb model in crash barriers by ...
http://www.dynalook.com/european-conf-2009/B-V-01.pdf
Layout, Validation and Benchmark of an all new Frontal Offset Barrier FEM Model: For the customer, passive safety is one of the driving reasons for the decision when buying a new car. To ensure high safety standards, passive safety is demonstrated in vehicle crash tests. Instead of vehicle to vehicle crash tests, one vehicle is replaced by an aluminium honeycomb based crash barrier. This barrier represents the front of a vehicle by the shape, the deformation behaviour and the energy absorption. Using Finite Element ...
http://www.dynalook.com/european-conf-2009/B-V-02.pdf
SuperLIGHT-CAR - the Multi-Material Car Body: Over the last years, total vehicle weights have risen significantly. With their direct influence on the power demand of vehicles, the reduction of weight is one among other measures in order to decrease the fuel consumption and CO2-emissions. The European project SuperLIGHT-CAR (SLC) is aiming at a weight reduction for the body-in-white (BIW) of a compact class passenger car, following the multi- material approach. By this, the perfect ...
http://www.dynalook.com/european-conf-2009/B-V-03.pdf
An Investigation of the Application of Bolt Pre- Stress and its Effect during Low Speed Impact Loading: This report is an initial investigation in to the effect of pre-stress of bolts during impact. The conclusions are not definitive but do indicate that for large strain analysis the effect of pre-stress in bolts is minimal. The effects are more noticeable for lateral impacts than in axial impacts. Further investigation is required to determine the effects of including friction and for other bolted configurations. This report is not an AMEC ...
http://www.dynalook.com/european-conf-2009/B-VI-01.pdf
A Rate-Dependent, Elasto-Plastic Cohesive Zone Mixed-Mode Model for Crash Analysis of Adhesively Bonded Joints: Presently, there are various cohesive zone models implemented in LS-DYNA. The simplest one consists of a bi-linear traction separation-law in both modes I and II. Further models allow more complicated shapes of the traction-separation law, such as the material model of Tvergaard and Hutchinson or the General Cohesive Zone Model. However, none of these implemented models consider rate-dependency or effects of plasticity. Crash-optimized ...
http://www.dynalook.com/european-conf-2009/B-VI-02.pdf
Modelling and predicting spotweld failures in automotive crash structures: The project has developed spotweld failure models capable of industry application for a range of steel grades to support development of automotive products, and their compliance to international crash safety requirements. An important consideration in this project is a requirement to balance the cost to develop the data input to models and their application capability in CAE based crash simulation tools to predict spotweld failures. Shear ...
http://www.dynalook.com/european-conf-2009/B-VI-03.pdf
New Design of Roadside Pole Structure: Crash Analysis of Different Longitudinal Tubes using LS-DYNA: This paper is an investigation into the design of an energy absorbing street pole, concerning the frontal impact of a vehicle. With design engineers now are looking at other ways to improve vehicle occupant safety by focusing on the advantages that can be achieved by improving the crashworthiness of street furniture. The study of axial crush behaviour of metal materials are investigated along with a number of variables such as ...
http://www.dynalook.com/european-conf-2009/B-VI-04.pdf
Forming simulations based on parameters obtained in microstructural cold rolling simulations in comparison to conventional forming simulations: This work demonstrates a first approach of using virtually obtained material properties as input for forming simulations. The necessary parameters to apply a Barlat-Lian89 yield surface are computed in the so called “Virtual Lab”, which performs FE-simulations on previously cold rolled volume elements to predict the distribution of grains. The resultant stress-strain-curves serve as input parameter for a deep drawing simulation. For ...
http://www.dynalook.com/european-conf-2009/C-I-01.pdf
Investigation on Simulation of Buckling of Aluminium Sheet Alloys: The lack of accuracy of buckling prediction in forming simulation is widely known. This is mainly caused by insufficient element stiffness as well as a very simplified strain path but not sheet thickness dependent buckling criterion. Within this contribution a methodology for investigating such issue is developed. This paper also reveals possibilities concerning an experimental analysis of buckling sensitivity of AA6016 aluminium sheet metal ...
http://www.dynalook.com/european-conf-2009/C-I-02.pdf
A Real World Approach for using LS-DYNA to Achieve True Springback Compensation on SS Components During Forming: Springback is every tool designer’s nightmare. A tool designer can make a die adjustable for some areas that need to be over-hit. Most parts are sprung throughout their entire surface. In these cases the entire part would need adjustment. Almost every time the die always requires a re-cut/re-work to put the part in spec. This re-work and re-cut is a time consuming, trial and error method that takes shop resources which typically are not ...
http://www.dynalook.com/european-conf-2009/C-I-03.pdf
Using LS-Dyna for Hot Stamping: Presented is a methodology for finite element modeling of the continuous press hardening of car components using ultra high strength steel. The Numisheet 2008 benchmark problem BM03 [1] is selected as the model problem to be solved. LS-DYNA [2] has several features that are useful to numerically model hot sheet metal stamping, such as: (1) modeling high rate dynamics for press forming; (2) conduction, convection and radiation heat transfer; ...
http://www.dynalook.com/european-conf-2009/C-II-01.pdf

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7th European LS-DYNA Conference

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