Event : JAPAN LS-DYNA Users Week 2006

JAPAN LS-DYNA Users Week 2006

Users Conference Program

Tuesday, September 19 / Wednesday, September 20

Abstract

Tuesday, September 19 / Wednesday, September 20

*The contents of the program may be subject to change without notice.

Tuesday, September 19

New Developments in LS-DYNA Dr. John O. Hallquist, Livermore Software Technology Corporation(LSTC)
General Session (1)
Based on the recent trend in CAE and requests from the global users, LSTC's goal for software development and project for developing LS-DYNA and other related software will be presented in association with the key terms of multi-physics, multi-stage, and multi-processing. Furthermore, features and applications of the latest version of LS-DYNA currently being developed will be presented.
Continuous simulation of vehicle run and crash using LS-DYNA Mr. Toshikazu Torigaki, NISSAN MOTOR CO., LTD.
Occupant injuries due to an automobile crash are influenced by various running conditions with occupant posture changes before an impact. Therefore, it is necessary to continuously simulate before and after an impact so that resultant injuries may be analyzed. A vehicle model that can run and crash are developed. Methods to stabilize and speed up computation in running simulation and to efficiently switch to crash simulation are discussed.
A material model and some numerical techniques for accurate simulation of springback Prof. Fusahito Yoshida, Hiroshima University
A model of large-strain cyclic plasticity (Yoshida-Uemori model) for accurate simulation of springback, it modeling and some examples of simulation on high strength steel sheets, is presented. Further, a numerical algorithm for sheet stamping simulation taking account of deflection of dies, as well as a technique of springback compensation based on FE simulation, are proposed.
Automotive Engineering Session (1) Safety Technology
Current situation and problems in CAE analysis on car seat structures Mr. Yasuhiro Sugiura, TOYOTA BOSHOKU CORPORATION
There is no limit for the demand for improving the automobile performance and efficiency such as lighter bodies, better maneuverability, and enhanced safety. Especially, the seats are highly important as they are directly associated with the safety of the occupants. Also, there is a common tendency to shorten the development time to meet the trend of the market. In this presentation, the current situation and problems in CAE are discussed focusing on the CAE applications in automotive design for achieving high performance while shortening the development time.
An Example Of Evaluation Procedure For Frontal Airbag Sensor Response By CAE Mr. Masahiro Awano, Mitsubishi Motors Corporation
It is well known that the airbag is the standard equipment for passenger protection. The airbag appropriate deployment timing during crash is controlled by the several sensor attached on the vehicle body structure. Also the sensor location must be selected carefully due to its response sensitivity. However, it has been very difficult to search the better location by prediction, because the crash phenomena has unknown scatter. In this presentation, the scatter consideration CAE study is applied to evaluate the sensor location prediction. As a result, the robust (stable discriminability) position requested by the sensor performance is visualized and provided its validity.
Simple prediction method for the edge fracture of steel sheet on the vehicle collision - Evaluation of fracture limit from the edge using small sized test pieces - Mr. Kenichi Watanabe, KOBE STEEL, LTD.
At vehicle collisions, fractures occur from the edge of steel sheet. Existence of any fracture has an influence on the accuracy of vehicle crash simulations. In order to obtain a simple evaluation index of the fracture limit, fracture limits around the holes processed using several methods were measured. It was clarified that these fracture limits are represented by a combination of the elongation and the hole expanding ratio of steel sheets.
Simple prediction method for the edge fracture of steel sheet on the vehicle collision - Edge fracture prediction using CAE - Mr. Kimihito Koyanagi, Toyota Auto Body Co.,LTD.
The fracture of the steel sheet generated in the vehicle collisions has a large contribution to vehicles modification, and, as for it, consideration of the steel sheet fracture for the improvement in prediction accuracy by vehicle crash simulations is important for it. It examined by the hole attaching hat type test piece having bent static three points, and the fracture strain of holes was measured. The three points bent test was reproduced in FEM, and relation between element size and a fracture strain value was clarified for the holes strain value as compared with the examination.
Crash Analysis Engineering Session
Bird Ingestion Analysis for Aircraft Jet Engine Mr. Rintaro Kajiwara, Ishikawajima-Harima Heavy Industries Co.,Ltd.
The event in which birds strike an aircraft jet engine during the flight is called a bird strike or a bird ingestion. Since the bird ingestion happens at a certain rate, aircraft engines should be designed to have the enough strength against the impact load of the bird ingestion in order to maintain the aircraft safety. Fan rotor blades especially are damaged most seriously due to the bird ingestion. Therefore it is very important to evaluate their damages accurately in the design phase. The examples of bird ingestion analyses which are conducted in the jet engine design process will be presented.
The Drop simulation for a Package Design with the pulp mould cushion. Mr. Hiroto Ido, SONY corporation
In the package design for the mid-range weight products, the pulp mould cushion, which is made from recycled waste-paper and corrugated fiberboard, is often used as an ecologically friendly material. In the conventional package design process for the pulp mold cushion, the stiffness against the drop impact has been evaluated with the prototype model and the drop test. In this paper, we study the numerical simulation technology for the package design, to predict the phenomenon in the drop test and to reduce the design cost for the modification of the mould tools.
Fracture Strength Analysis of Reinforced Concrete with Steel Plate Against High Speed Projectile Mr. Kazukuni Niwa, Terrabyte Co., Ltd.
There is concern about terrorism attacking the nuclear power plants using projectile such as an aircraft. One of the methods to improve the RC structure impact strength is to attach the steel plate onto the concrete using fixing studs. In this paper, impact strength of the steel plate concrete against high-velocity projectile is analyzed, and compared with the existing experimental results to demonstrate that realistic results can be obtained in respect to the failure mode and deformation of the steel plate and concrete.
Automotive Engineering Session (2) Barrier/Dummy/Impactor
Development of Aluminum Honeycomb Model using Shell Elements Mr. Shigeki Kojima, TOYOTA TECHNICAL DEVELOPMENT CORPORATION
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 keep minimum mesh size, and compressive strength is controlled by thickness of shell elements. New modeling was applied to an offset deformable barrier model, and full vehicle crash analysis was performed. The result of offset frontal collision analysis with a new honeycomb model showed much better correlation with test results than with modified material type-126 solid elements.
Current Developments in Honeycomb Barrier Modelling Mr.Richard Sturt, Ove Arup and Partners Limited
New barrier models are now being developed that use advanced features of LS-DYNA, such as honeycomb strength versus loading angle, and the adhesive material model. This paper describes the construction and correlation of the models.
JRI Solution's FE Model library for vehicle safety analysis Mr. Takahiko Miyachi, JRI Solutions, Ltd.
For crashworthiness of the vehicle, design, the standardized parts, impactors are required. Information of validation result and development schedule of the library of FE models as dummies, aluminum honeycombs for energy absorption, pedestrian impactors for regulations and/or NCAP as well as tires which are important load path for crash, will be introduced.
Development of Side Impact MDB Model using Shell Elements Mr. Yoshiki Takahira, TOYOTA TECHNICAL DEVELOPMENT CORPORATION
This paper describes a development of new side impact MDB finite element model that an Aluminum honeycomb is modeled by using shell elements. In previous study, the new modeling method for an Aluminum honeycomb was applied to ODB model and an accuracy of the offset frontal collision analysis was improved drastically. In this study, the new modeling method was applied to MDB model and full vehicle crash analysis was performed. The result of side impact collision with new MDB model showed much better correlation with test results than with modified material type-126 solid elements.
Production Engineering Seminar
Examples of CAE application in production engineering department. Mr. Tomohiko Mita, MITSUBA Corporation
In the analysis for design optimization of press die, we studied the proper die shape and dimensions to achieve the desired thickness of plate with JSTAMP/NV. We evaluated the plate thickness, which is one of the indicators of material fracture, using quality engineering and CAE, and succeeded in calculating die parameters for ensuring sufficient plate thickness. In order to examine the effect due to thermal shrinkage of the casting part, we obtained temperature distribution data from the casting flow analysis first, and then performed stress analysis with the data using LS-DYNA. In this way, we were able to do stress and deformation analysis considering the influence of casting flow.
Sheet forming of partially softened aluminum alloy sheets. Mr. Takeshi Nishiwaki, Nagoya Municipal Industrial Research Institute
The effect on the deep drawability and the stretch formability of partially softening was investigated for high strength aluminum alloy sheets. The peripheral part of the 6061-T6 circular blank was locally heated to be softened using ring shape heated dies. The effect of partially softening on the formability and the optimal softened region to obtain the best formability can be predicted by the numerical analysis using LS-DYNA.
Finite Element Simulation of Joining of High Strength Steel and Aluminum Alloy Sheets Using Self-Piercing Rivet Prof. Ken-ichiro Mori, Toyohashi University of Technology Mr. Yohei Abe, Toyohashi University of Technology Mr. Toru Kato, Nippon POP Rivets and Fasteners Ltd.
High strength steel and aluminum alloy sheets were joined with a self-piercing rivet. It is not easy to weld the aluminum alloy and high tensile strength sheets by mans of conventional resistance welding because of very different melting points. To obtain optimum joining conditions, joining defects are categorized into separation of the sheets and necking of the lower sheet. The joining range of the high strength steel and aluminum alloy sheets was extended by optimizing shapes of dies in the finite element simulation LS-DYNA.
Spring-back Analysis by Using Material Models Considering Bauschinger Effect Mr. Eiji Isogai, Nippon Steel Corporation
Stress-strain relations in the loading-reloading process were measured by simple shear test and material parameters of material models were determined. FEM analysis of spring-back processes in draw bending was also performed and the effect of hardening models on analytical prediction of spring-back was investigated.

Tuesday, September 20

Spotweld modelling with solid elements in LS-DYNA and PRIMER Mr.Richard Sturt, Ove Arup and Partners Limited
Automotive Engineering Session (3) Simulation Technology
Mesh-independent spotwelds are commonly modelled in LS-DYNA using beam elements and MAT_SPOTWELD. However, some users prefer solid elements because the spotweld forces can be transmitted to the panels over a realistic area. There have been many recent advances in LS-DYNA for spotweld modelling using solid elements, such as new failure criteria in MAT_SPOTWELD and the ability to define a single spotweld with a mesh of several solid elements. The paper illustrates these LS-DYNA capabilities, and demonstrates how solid element spotwelds will be supported in PRIMER 9.3.
Introduction of "Virtual-Digi-Tire for Motorcycle" as Test User Mr. Shigeru Fujii, YAMAHA MOTOR CO.,LTD.
We have used "Virtual-Digi-Tire for Motorcycle" as test users. In this presentation two ways of our usage will be introduced. One is a usage that calculates data for the tire model for the running simulation of motorcycles for theoretical maneuverability examination. Another usage is clarification of the mechanism of the tire force generation. As one example, we tried to understand the distribution of frictional forces under largely cambered situations. Through that we try to obtain hints of optimum design of motorcycle considering tire characteristics.
Simulation for the development of automobile tire with sponge Mr. Masaki Shiraishi, SRI R&D Ltd.
Reducing noise is very important performance for comfortable driving. Tire is much dependant for road noise or impact noise, and it is difficult to reduce noise from tire cavity. In order to reduce tire cavity noise, we developed the techniques of setting the sponge in tire cavity. But the development by experiment was difficult because this phenomenon was invisible at internal tire and air behavior. So we developed this technique by simulation and it was useful.
Integrated Areas Session
Viscoelastic Analysis using LS-DYNA Mr. Masaki Fujikawa, Mechanical Design & Analysis Corporation
The authors introduce examples of the viscoelastic - hyperelastic problem in rubber materials. Firstly, we present the storage/loss moduli measured using the Dynamic Measurement Tester and calculation techniques of the master curve based on W.L.F. equation and generalized Maxwell model to input into LS-DYNA.Secondly, we introduce the hyper-elastic data and the approximation technique of Ogden model from the data. Thirdly, we calculate the hyper-viscelastic analysis, and confirmed that the results obtained by the LS-DYNA are good agreement with the theoretical one. Finally, Using these data, we evaluate the characteristics of the vibration-proofing.
Fluid Structure Coupling Technique Using LS-DYNA and Application Example by User JRI Solutions, Ltd.
The coupling analysis of the fluid and structure using LS-DYNA has been more required in a variety of fields recently. To cover the wide range of the analytical purposes, LS-DYNA continues to be developed. The first half of the presentation will discuss the method for coupling the fluid and structure. In the latter half, the user's application at a practical level will be presented.
Plastic Product Design using integrated technology of CAE and CAO (Computer Aided Optimization) Mr. Yoshiaki Togawa, Sumitomo Chemical Co., Ltd.
Plastic CAE is used as indispensable technology in the plastic product design today. Having passed through the first generation (dawn-development) of plastic CAE technology in the 1980s and the second generation (maturing) in the 1990s, we are progressing toward the era of automation, optimization and integration (third generation) of CAE using CAO (Computer Aided Optimization) in the 2000s. By integrating CAE technology and the CAO technology, the automatic optimal design of a plastic product is attained and much more shortening the period of a product design, reducing development cost, and improving the quality and the performance of a product can be expected. Moreover, it becomes the powerful support technology of material development. In this presentation, the outline of the integrated technology of the plastics CAE and CAO that we have developed, some application examples, and the integrated design optimization system for the plastic products of our company are described.
New Technologies Session
Current and Relevant Knowledge for Automotive Safety Engineers: Highlights from the 2006 German SafetyUpdate Mr. Rainer Hoffmann, EASi Engineering GmbH Mr. Masahiro Okamura, Agile Network Co.
SafetyUpDate is a new automotive safety concept, pioneered by EASi Engineering GmbH in 2003. Since its inception it has attracted every year 200 European automotive safety experts. The SafetyUpDate aims at delivering the latest knowledge and developments in automotive safety engineering to the participants. It covers requirements with the latest findings in biomechanics and accident research as well as news in legal and NCAP compliance testing. Most recent development strategies are discussed for frontal and side impact, pedestrian safety and active safety applications. The systematic view is completed by an update on the latest development in safety testing and simulation technology. The in-depth presentations at the SafetyUpDate are given by the most renowned experts from academics, industry and government organizations. The highlights presentation will give a condensed overview on the SafetyUpDate held in April 2006 in Aschaffenburg, Germany.
Simulation of damage and failure in thin shell structures, a review of current LS-DYNA capabilities Mr. Paul Du Bois
In many different applications engineers are faced with the need to simulate rupture in thin sheets. The parts could be metallic such as car body panels or polymeric such as bumper fascia and inner trim panels. For either material a fully predictive simulation cannot be considered state-of-the-art today. In this paper we will compare the different approaches that are currently available in the LS-DYNA software. The principal aspects of failure simulation techniques that will be discussed are discretisation, regularisation, material law and damage formulation. Recent additions to the SAMP material model for plastics will also be introduced.
The Products and Development Project of JRI Solutions Mr. Kimihiro Hayashi, JRI Solutions, Ltd.
CAE technology has become essential in entire phases of manufacturing including R & D, design, and production. JRI-SOL offers products and services focusing on crucial solutions for CAE engineers who are continuously improving the products. Our future plan for product developments and services will be presented.
General Session (2)
The Use of LS-DYNA at NASA, including the Columbia Accident Investigation and the Space Shuttle Return to Flight Dr. Kelly Carney, NASA Glenn Research Center
Four years ago, LS-DYNA served NASA as an analytical tool in niche areas of research, such as aircraft crash worthiness and jet engine fan blade containment. The accident of the Space Shuttle Columbia changed the role of both the tool and the research engineers using it. The investigation into the cause of the accident, and the eventual demonstration that foam impacting the leading edge of the wing resulted in the loss of the vehicle, proved the great worth to NASA of this class of analysis. A large test and analysis program was initiated to determine material properties, create material models and finite element meshes, and verify these analytical models through ballistic testing. The models were then used to predict damage and failure thresholds, and to eventually re-certify the Space Shuttle for Return to Flight. LS-DYNA is now being used throughout NASA to assess potential impacts to launch vehicles and aircraft, including aiding in the design of the new Crew Exploration Vehicle.

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