[Keynote Speech]
Lessons learned from crash analysis by the Earth Simulator
Mr.Masayuki Yoshikawa, TOYOTA MOTOR CORPORATION
Vehicle crash analysis containing 14,000,000 elements, which was the largest one in 2005, was performed using the Earth Simulator. Conventional modeling adopted 5mm element length and detailed feature on white body might be omitted. In contrast, the length of 2 mm elements were used in this simulation and realistic geometry could be included. As the results, a certain prediction for floor acceleration, which used to be difficult to obtain so far, could be done and this study revealed that consideration on modeling of detailed geometry was needed for full vehicle crash analysis.
10/7 11:05-11:50
[Guest Speech]
Analytical Modeling of Origami and Its Academic Applications-mainly for Engineering Applications
Prof.Taketoshi Nojima, Innovative Research Initiatives, Tokyo Inst. Tech.
The present author proposed 'Origami Technology', and envisages the formation of a new discipline;mathematical analysis of Origami and its development in academic applications especially in engineering use.
Origami structures consisting of zigzagged faces have foldable/deployable functions as well as solidification characters. Models presented in this presentation include typical foldable/deployable thin cylinders, conical-shaped membranes, circular sheets which may be folded or wrapped. These shape-changeable origami models are analytically designed by folding or creasing a flat sheet or a thin plate into a 3-dimentional shape. New types of Ultra-light 3-D honeycomb core models and a newly developed core panel named "dia-core" (consisting of 2 periodically dimpled panel pieces) are also presented for use in building such as aerospace structures.
The former models are designed by analyzing the helical patterns or structures often found in living organisms, because such helical structures are easily deployed due to the presence of fewer dynamic restraints. The latter are developed on a purely geometrical basis.
As for academic applications of Origami modeling, two examples are shown; the phyllotaxis of leaves or flowers showing helical patterns, and axial buckling and torsional buckling of cylindrical tubes and conical shells are explained by using origami modeling.
10/7 12:00-12:45
[General Session(1)]
Research Update on Vehicle Compatibility, Child Occupant Safety Research, and IIHS Frontal Center Pole Impact.
Prof.Cing-Dao (Steve) Kan, The George Washington University
This presentation will provide some updates of current research activities at National Crash Analysis Center on the following research topics:
Vehicle Compatibility;
Child Occupant Safety Research, and IIHS Frontal Center Pole Impact.
10/7 14:00-14:30
[Vehicle Body Structure Session]
Crash analysis of the rail vehicle for Europe
Dr.Takashi Yamaguchi, Hitachi, Ltd.
Hitachi, Ltd. has been developing the rail vehicle for U.K. and now the test run is going in the field. This presentation shows our effort to ensure crashworthiness of the body of the vehicle.
10/7 14:30-15:00
[Vehicle Body Structure Session]
Identification System for Plastic Material Models Using the Genetic Algorithm And Its Application to Crash Simulations for Automotive
Mr.Masaru Kanai, FUJI TECHNO-SERVICES CO.,LTD.
We have developed an identification system for plastic material models based on the genetic algorithm which improves the accuracy of crash simulations and provides better environment for CAE analyses. The new system automatically generates appropriate stress-strain curve data of materials according to their load-displacement characteristics in the tensile test. The paper describes features of the identification system as well as an application of the system to a crash analysis for automotive plastic components.
10/7 15:30-16:00
[Vehicle Body Structure Session]
Investigation on Crashworthiness Simulation Accuracy Improvement with Sheet Metal Forming Process.
To improve the accuracy of crashworthiness simulation, it is important to consider the effects of metal forming. However, this approach was difficult in practices since analyzing the stamping simulation in detail requires much work. This paper describes the influence of residual strain, work hardening and metal thickness changes resulting from the stamping process on the crashworthiness simulation. In almost all impact load cases, the results show that deformation is reduced by the work hardening effects. These results are verified by actual experimental data.
10/7 16:00-16:30
[Vehicle Body Structure Session]
Development of the roof strength analysis method for snow pressure with LS-DYNA
Mr.Ken Furui,TOYOTA AUTO BODY CO.,LTD.
If sudden transformation occurs in analysis of roof strength for snow pressure with previous method, a calculation sometimes emits it. In this report, we apply a switching method from implicit to explicit when convergence is not good to analysis of roof strength for snow pressure. And we compared the test result and the calculation result (deformation and buckling load), and confirmed the precision.
10/7 16:40-17:10
A Study of FE simulation models for evaluating impacted RC plate strength based on the existing experimental data.
Mr.Toru Kadoguchi, Terrabyte Co., Ltd.
Great interest in protection of important buildings, i.e., nuclear power plant, against aircraft attack has been taken recently. Especially improvement of accuracy for the estimation of impact strength of RC wall considering fracture on the reverse side of impact and penetration hole is expected. It is difficult to estimate damage and scattering of concrete if a conventional procedure, in which load-time function derived from the impact of projectile against rigid wall is applied on RC surface, is used. And the modeling of fracture using element deletion proposed by Niwa et al. cannot be applied in this conventional procedure. In addition, the criteria of element deletion for fracture depend on element size and more objective criteria for fracture is necessary. In this presentation ,a more accurate model considering the fracture on the reverse side of impact and the penetration hole on RC wall is investigated and the effectiveness of the model is shown.
10/7 17:10-17:40
Numerical Implementation of Hyperelastic-Viscoplastic-Damage Model for Rubber-Like Solids
Dr.Masaki Fujikawa, Mechanical Design and Analysis Corporation
This paper presents a constitutive model of rubber-like solids, and numerical implementation of finite element is introduced. The proposed model consists of two parts. The first one is a Hyperelastic model, and the second one possesses parallel viscoplastic models based on a free-energy concept, which express strain-dependency of energy absorbing behavior of rubbers. This paper shows the implicit integration and consistent tangent modulus of the model. Then the model is implemented in a finite element program(LS-DYNA) and applied to some numerical examples to discuss the performance.
10/7 14:00-14:30
[Manufacuturing Session]
Case Studies of CAE Analysis with Quality Engineering for Die Design
Mr.Tomohiko Mita, MITSUBA Corporation
This paper introduces examples of CAE analysis using quality engineering in die designing process. Quality engineering is effective for robustness evaluation. In die designing, we evaluated process feasibility, useful life of press/forging die and others by CAE analysis incorporating quality engineering. As a result, we succeeded in designing die with high robustness in a short period of time.
10/7 14:30-15:00
[Manufacuturing Session]
CAE application for hot tube bulge forming process
Mr.Yuichi Nagai, Honda Engineering Co., LTD.
Hot bulge forming of aluminum alloy pipe is applied to the suspension parts such as sub-frames recently. We introduce the case where CAE is applied to three-dimensional shape modeling of the bulge forming die.
10/7 15:30-16:00
[Manufacuturing Session]
Effort on Press Forming Simulation -A Study on Improvement for Accuracy of Springback Prediction and Compensation Technique-
Mr.Sou Suzuki, KIKUCHI Co.,Ltd.
Our effort on press forming simulation concerning investigation and examples for the improvement of accuracy for springback prediction and effective procedure to produce compensated tooling will be presented.
10/7 16:00-16:30
[Manufacuturing Session]
Recent developments of JSTAMP
Mr.Tomoki Hamada, JRI Solutions, Ltd.
The recent development subjects of JSTAMP,an integrated forming simulation system, are introduced with various examples. And our vision and effort on technical developments in the manufacturing field are also introduced.
10/7 16:40-17:10
[Manufacuturing Session]
Design Optimization of Nonlinear Dynamic Systems using HEEDS with LS-DYNA
Dr.Ron Averill, Red Cedar Technology
The application of HEEDS and LS-DYNA to the design optimization of nonlinear dynamic systems will be described, including applications in crashworthiness of automotive systems.
10/7 17:10-17:40
[Manufacuturing Session]
LS-DYNA Meshfree Method in Solids and Structures: Current, Future and Its Industrial Applications
In this presentation, an update on LS-DYNA meshfree method for solids and structures will be given. Several features were developed in the past few years to solve specific challenging problems and to improve the efficiency. This talk will emphasize on a semi-Lagrangain formulation in foam materials, an adaptive meshfree scheme in metal forming analysis and a discrete meshfree approach in the failure analysis of brittle materials. Several practical examples are included to demonstrate these capabilities.
At the tire tread, there are some grooves for hydroplaning or some other purposes. This is called the tire tread pattern. But this generates ‘tire pattern noise’. The pattern noise is uncomfortable for vehicle passengers and circumferential people. For the tire development, it is very useful and important to simulate the pattern noise and understand the mechanism of generating the noise. In this report, the tire pattern noise simulation using both of the tire structure analysis and the aero dynamic analysis is introduced.
10/8 10:00-10:30
[Runninng Simulation Session]
Meshfree microscopic analysis of CB filled rubber and application of it to multi-scale simulation of tire
Dr.Masataka Koishi, The Yokohama Rubber Co., Ltd.
In this study, we apply the meshfree microscopic analysis of carbon black filled rubber to the multi-scale simulation of tires. We use EFG in LS-DYNA for the meshfree analysis. In this procedure, the existence of homogenized constitutive law is assumed, and multi-point constraint technique is introduced for periodic boundary conditions so that the two-scale boundary value problem derived from homogenization theory can be solved approximately. In conclusion, the meshfree method has been found to be an effective approach for the numerical modeling and design of rubber compounds under small and large deformation. Several issues involving the influence of morphology of fillers to the mechanical properties of rubber compound will be addressed including 3D multi-scale simulation of rubber compound and tire. The developed procedure based on meshfree method is useful for practical multi-scale simulation of tires and other rubber products.
10/8 10:30-11:00
[Runninng Simulation Session]
FSI Analysis of shock absorber dampers
Mr.Shozo Tokumitsu, KYB Corporation
To get a good response of the shock absorber , a linear damper force characteristic is requested in a low-speed region. The dynamic characteristic of typical valve assembly, was clarified with ls-dyna FSI. The combination of appropriate stiffness and numbers of laminated thin disks and supporting spring , is important to improve dynamic response of actual product.
10/8 11:10-11:40
[Runninng Simulation Session]
Vehicle Dynamics Simulation by using Steady State Rolling Analysis of Tires
Mr.Tatsuya Fukushima, NISSAN MOTOR CO., LTD.
In case of driving simulation using vehicle model containing tire FE model, at first, dynamic analysis for straight driving with constant velocity on flat road surface is performed. After the vertical vibration of the body supported with suspension under the gravity loading is damped out, simulation for cornering and braking can be done. The frequency of the vibration is around one second, and cpu time of damping simulation is relatively large in total cpu time of entire simulation and cannot be negligible. In order to save time, static approach should be applied for the first phase of the simulation for straight driving with constant velocity. For this purpose, deformation of tire under constant rotation should be simulated with static analysis. This paper shows the result using "Steady State Rolling" capability which was newly developed for FE model of tire.
10/8 9:30-10:00
[Crash/Safety Session]
Review of Optimization and Robustness Applications with LS-OPT
Dr.Heiner Mullerschon, DYNAmore GmbH
This paper gives and overview of optimization and robustness studies applied in collaboration with German Automotive Companies. Methodologies and different approaches are discussed and compared. Capabilities of LS-OPT and D-SPEX are demonstrated. D-SPEX is an advanced post-processor based on results of optimization or stochastic studies done with LS-OPT.
10/8 10:00-10:30
[Crash/Safety Session]
Development of the Advanced Finite Element Model for ODB Impact Barrier
Mr.Paul Tattersall, Cellbond Composites Ltd.
Frontal Offset tests are carried out by a large number of test houses worldwide, according to the European regulation and to FMVSS, as well as by EuroNCAP, Australian NCAP, JNCAP and IIHS. In the frontal offset test, only one side of a vehicles front end hits the deformable barrier, which means that a more concentrated area of the vehicles structure must sustain the impact of the crash rather than the whole width of the vehicle. This paper represents the new methology to create and validate the Finite Element model for the Offset Deformable Barrier (ODB). The Cellbond ODB barrier has been investigated which consists of two different sized aluminium honeycomb blocks in main body and bumper partially covered in aluminium skins. The explicit LS-DYNA was used to analyze the model and validate against experimental test data. Number of static compressive tests performed at different angles to characterize Yielding Function of aluminum honeycomb parts and corresponding Material Card data. Strain-rate scale factor curves are also defined to convert static test results into suitable data in honeycomb material card during the analysis procedure. Adhesive properties are obtained using Climbing Drum, T-Peel, Tensile and Plate Shear test results. The barrier was subjected to four individual test conditions with different impactor and impact speeds. The Final comparison on overall results represents a good correlation between test data and CAE results on both Flat-Wall and Pole tests.
10/8 10:30-11:00
[Crash/Safety Session]
Automating and extending PRIMER and D3PLOT using JavaScript
Mr.Richard Taylor, Arup
A JavaScript interpreter has been embedded within PRIMER, D3PLOT and Reporter. Users can write their own programs to create and modify LS-DYNA data, or calculate and display their own special results. This paper presents some examples.
10/8 11:10-11:40
[Crash/Safety Session]
Modeling techniques for predictive and robust dummy models
Mr.Ulrich Franz, DYNAmore GmbH
In many load cases models from third parties are used during vehicle development. The authors work since many years on different dummy models in cooperation with the German automotive industry. The models are world wide used by the LS-DYNA user community. The paper describes the methodology of the development and the techniques applied to achieve reliable, robust and predictive models.
10/8 11:40-12:10
[Crash/Safety Session]
"Mature concepts" through integrated CAD and CAE processes in catia V5 with LS Dyna
Mr.Yukiyoshi Taguchi, Tecosim Japan Ltd.
In the automotive industry, as in other fields, the early phases of development are determining for the key performance data and production costs of a vehicle. People in this industry are now also already using high-performance programmes for virtual design (CAD) and virtual testing (CAE). The two process chains are, however, still largely separate from one another at present, and data from what are already complex CAD/CAE programmes in themselves have to be exchanged across breaks in the media. Especially in the early concept phases of an automotive development, however, these interfaces should be avoided, for reasons relating to time and costs. It would also be desirable to achieve a common user interface for design and simulation, on the basis of closely-meshed communications. The content of this publication is the integration of a concept development tool for planar geometries in connection with an automatic cross-linking tool in Catia V5. In particular, the development of a fully parameterised planar description in Catia V5 is demonstrated. Using the simple basic objects point, spline and surface, typical vehicle geometries and cross-sections can quickly be created. A library of cross-section forms simplifies the finding of suitable connections. The combination of this concept development tool integrated in Catia V5 with a high-performance finite element planar cross-linkage package within the same user interface makes it possible to conduct rapid virtual testing and optimising of an identified geometry. The set of parameters for the model creates the basis for fully-automated optimisation processes here. The optimised model is transferred directly and without breaks in the media to the detailed design, thanks to the integrated environment. Attributes such as component name, component hierarchy, sheet thicknesses, enclosed area information etc. are retained. The finite element component cross-linking operation remains completely in the background with this integrated process (batch process). FE information can be defined globally or locally. Changes in the geometry are immediately taken into account through re-linking of components. This puts the car designer in the position of also being able to perform cross-linking tasks for colleagues, using the calculation. Based on this new technological background, FE Code LS Dyna was used to optimise an FE car structure considering side crash scenario. The optimsation was done in an fully automated process using key features of the LS dyna code.
10/8 13:25-13:40
[General Session(2)]
Introduction of JVISION Ver.3.0
Mr.Toshiki Moritoh, JRI Solutions, Ltd.
This presentation will show the Information prior to release of JVISION/v3.0 and a road map.
10/8 13:40-14:25
[General Session(2)]
Simulation of Polymeric materials in LS-DYNA
Mr.Paul Du Bois, Hermes Engineering NV
Material failure is very often preceeded by some kind of instability phenomenon. The numerical techniques for simulating material instabilities will be illustrated using the examples of necking in metals, shear banding in Plexiglas and crazing in thermoplastics. The correct simulation of instabilities must be seen as a necessary condition for the prediction of failure.
10/8 14:25-15:15
[Keynote Speech]
Preliminary Results for an Isogeometric Shell
Dr.David Benson, University of California, San Diego
Preliminary results for isogeometric shell and solid elements using LS-DYNA will be presented. Isogeometric elements are use the same basis functions as CAD programs, namely nonuniform rational B-splines (NURBS), which can represent conic sections exactly. These functions are very smooth, allowing shell elements without rotational degrees of freedom to be formulated without any loss of accuracy. Additionally, the time step size for the higher order elements is not reduced as much as for higher order elements based on Lagrangian polynomials. Taken together, these features make isogeometric elements attractive for achieving higher order accuracy in nonlinear industrial problems such as metal stamping.
10/8 15:35-16:05
[General Session(2)]
JRI Solution's product and support service
Mr.Kimihiro Hayashi, JRI Solutions, Ltd.
We,JRI Solutions has been developing/selling LS-DYNA, JSTAMP,ARUP Software,JVISION and so on. I will explain our developing plan and support services.
Contact
Users' Meeting Secretariat Engineering Technology Business Unit, JSOL Corporation
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