Wednesday, July 18 10:10-

[Keynote Speech]
Development of Ccrack Propagation Simulation Method by LS-DYNA

Mr.Tsuyoshi Yasuki, Toyota Motor Corporation

Direction of crack propagation sometimes depends on direction of grids. Newly developed method of simulating crack propagation can reduce direction dependency to grid. The method does not need to assume direction of crack propagation in grid generation.

Wednesday, July 18 11:00-

[Keynote Speech]
Methodology to Enhance the Quality of CAE - V&V -

Prof.Seiichi Koshizuka, The University of Tokyo

V&V(Verification & Validation) is a methodology to enhance the quality of CAE (Computer-Aided Engineering) and spreading in the world. In this lecture, the basic concept of V&V, progress in the world, progress in Japan and application examples are reviewed.

Wednesday, July 18 13:30-

[New technologies(1)]
The study of modeling for thick plate parts on crash analyses

Mr.Nobuyoshi Ishibai, Hino Motors Ltd.

In order to shorten the time required to develop crash and safety performance of vehicles and the man-hours required for such operations. it is imperative the accuracy of these of analyses be improved. Hino Motors will suggest the modeling for thick plate parts and methods for improving the accuracy of flat barrier collision analysis. Also the modeling and methods for obtaining acceptable experimental results on the initial trial will be presented.

Wednesday, July 18 13:55-

[New technologies(1)]
Unsteady aerodynamic analysis around oscillating Ahmed body by LS-DYNA ver.980.

Mr.Hiroyuki Sawamoto, TOYOTA MOTOR CORPORATION

This paper describes an aerodynamic effect of the Ahmed body model in sinusoidal pitch motion. This aerodynamic effect was analyzed by relation of pitching angle to lift coefficient. The numerical results were calculated by the CFD function of LS-DYNA ver.980. Those numerical results showed good agreements to wind tunnel test results reported in the past. The flowfield was investigated by using this numerical analysis result. The relationship of bottom surface pressure distribution to the lift coefficient clarified.

Wednesday, July 18 14:20-

[New technologies(1)]
Advanced Technologies Related to Crash Simulation for Optimum Combination of Structure and Materials -Fracture Prediction in Ultra High Strength Steel-

Dr.Akihiro Uenishi, Nippon Steel Corporation

Numerical simulation techniques are indispensable for the optimization of materials and structure. During crash events, occurrence of fracture has possibilities to alter drastically the following structural behavior. Here, fracture prediction especially for spot-welds of ultra high strength steels, including hot stamped steel, is studied and validated by using experimental results.

Wednesday, July 18 13:30-

[Manufacturing technologies]
Development of prediction technology of surface deflection based on sheet metal forming simulation

Dr.Hideo Tsutamori, TOYOTA MOTOR CORPORATION

As for the surface deflection occurs in the body design of the car, evaluation was difficult because the depth of the surface deflection is several 10 μm order. In this study, we developed the quantitative evaluation method for surface deflection match to sensory evaluation by inspector. And we also improved the FEM program that can consider the influence of thickness direction pressure. As the result, we confirmed that the developed method can predict the surface deflection occurred on body press panel.

Wednesday, July 18 13:55-

[Manufacturing technologies]
Techniques of prediction about ultra high strength steel in cold forming

Mr.Toru Tetaka, Yachiyo Industry Co., Ltd.

In this study, following techniques of JSTAMP for ultra high strength steel in cold forming are introduced.
- Accuracy of forming limit and spring back prediction in high-tensile steel (over 1180Mpa strength).
- Control techniques of spring back
- Effects of tool?fs deformation in spring back.
- Prediction of residual stress which affects delayed fracture.
- A possibility of cold forming in high-tensile steel.

Wednesday, July 18 14:55-

[Crashworthiness]
Prediction of Ductile Fracture of High Strength Steels with Cockcroft-Latham Fracture Criterion

Mr.Kenji Takada, Honda R&D Co.,Ltd. Automobile R&D Center

Cockcroft-Latham fracture criterion was applied to predict the fracture of high strength steels. Marciniak-type biaxial stretching test was carried out to measure the material constant of Cockcroft-Latham. Furthermore, Digital Image correlation was carried out to measure the Lankford parameters depend on the plastic strain and these experimental results were incorporated into Hill's anisotropic yield condition. The uniaxial tensile tests based on JIS No.5 tensile test carried out to investigate the Cockcroft-Latham. As a result, the accuracy of rapture strokes of LS-DYNA was improved. Next, Cockcroft-Latham was applied to predict the failure of spot welds. To simulate the local bending and warping deformations around the heat-affected zone, the discrete Kirchhoff triangle element was adapted. inally, LS-DYNA results had good correlation with experiments.

Wednesday, July 18 15:20-

[Crashworthiness]
High Strain Rate Tensile Test for Automotive Steel Materials

Mr.kentaro Sato, JFE Steel Corporation

The strain rates during car crash are distributed over a wide range, from 10-3 to103/s. In order to evaluate the crashworthiness of automobiles structure, it is very important to obtain accurate stress-strain (s-s) relationships. In the presentation, stress-strain relationships at high strain rates obtained with several types of tensile test machines were compared directly, and the characteristic of the curves will be discussed. Moreover, the behaviors of steel sheets in high strain rate deformation will be introduced for accurate FEM simulation for crashworthiness.

Wednesday, July 18 15:45-

[Crashworthiness]
Development of Spot Weld Rupture Evaluation Model for Crash Simulation

Mr.Motoki Higashiyama, Mazda Motor Corporation

For crash analysis of vehicle, beam elements are typically used to express spot welding. In a conventional model, however, this causes some issues such as intensive local deformation in elements around spot welding. In order to solve these issues, we developed a spot welding model with solid elements and verified its validity.

Wednesday, July 18 14:55-

[New technologies(2)]
Prior design of COR performance and the durability strength of the golf club by LS-DYNA

Mr.Yukihiro Teranishi, Mizuno Corporation

The biggest subject of concern of the golfer is a maximum flying distance of the driver shot. Even if it is said that one of the most important performance of the golf club is coefficient of restitution(COR) performance, it is not exaggeration.
A prior design by highly precise simulation is indispensable I maintain the maximum COR in the sweet spot for severe regulation about the COR of the golf club, and to enlarge a high COR area.
It is important equally that there is a highly precise prior design about durability strength for the high-speed collision repeatedly at the same time.
Therefore I perform highly precise simulation by collision analysis by LS-DYNA and,
by the golf development of Mizuno, perform the prior design that can satisfy COR and the durability strength of the golf club at the same time.

Wednesday, July 18 15:20-

[New technologies(2)]
Application of Simulation using Simpleware and DYNA for the Practice of Plastic Surgery

Dr.Tomohisa Nagasao, The medical faculty of Keio University

Plastic surgery, a specialty in the medical field, aims to restore body defects or deformities caused by trauma or tumors. Specifically, repair of fractured face bones, correction of congenital deformity of the chest or the skull, and reconstruction of breasts lost because of the removal of malignant tumors are conducted in plastic surgery. In making treatment plans for such operations, physicians need to predict the results of their treatments based on accurate knowledge about the biomaterials on which they are working. For the purpose of preoperative planning, we perform simulation using Simpleware & LS-DYNA and predict how the body transforms in response to surgical maneuvers. This presentation introduces the usefulness of computer simulation in the practice of plastic surgery. Computer-aided simulation is a prospective scientific field. This presenter wishes the audience take interest in the application of LS-DYNA for medical fields.

Wednesday, July 18 15:45-

[New technologies(2)]
On two-dimensional Slamming Impact Analysis of Wedge Shaped Obstacles considering Fluid-Structure Interaction (FSI)

Dr.Yasuhira Yamada, National Maritime Research Institute

Water impact (slamming) load is one of important design loads for ships, and damage due to slamming continues to happen as increase of ship speed and size. In the present study, a series of two dimensional water impact analyses of wedge shaped obstacles are carried out using LS-DYNA. Results estimated by LS-DYNA are compared with that obtained by conventional Wagner theory and applicability of fluid function of LS-DYNA is studied. Bottom shell plate is modeled by elastic-plastic material. Effects of rigidity of wedge bottom shell plate on pressure distribution as well as deformation are investigated with changing shell plate thickness. It is found from the present study that pressure distribution and impact force estimated by LS-DYNA have relatively good correlation with those obtained by Wagner theory. It is anticipated that the present numerical method can be applied to three dimensional analyses in the next step.

Wednesday, July 18 16:25-

JSOL Solution Introduction

Mr.Takahiko Miyachi, JSOL Corporation

LS-DYNA is getting more accurate, more robust and easy use as a market leader structural solver. These days, computer simulation is used not only for specialized people but for wider range of engineers as a standard tool. Here, not only the capability of solver, but substantial product, technical support, and engineering service are required as well to help utilization of LS-DYNA. We are happy to introduce JSOL's solution for LS-DYNA analysis as a technical leader.