| Project/Area Number |
09450045
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
UJIHASHI Sadayuki Tokyo Institute of Technology, Graduate School of Information Science and Engineering, Professor, 大学院・情報理工学研究科, 教授 (80016675)
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| Co-Investigator(Kenkyū-buntansha) |
INOU Norio Tokyo Institute of Technology, Graduate School of Information Science and Engineering, Associate Professor, 大学院・情報理工学研究科, 助教授 (70126308)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥10,900,000 (Direct Cost: ¥10,900,000)
Fiscal Year 1999: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1998: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1997: ¥6,900,000 (Direct Cost: ¥6,900,000)
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| Keywords | Helmet / head Protection Ability / Impact / Finite Element Method / Computer Simulation / Drop Weight Test / HIC / Evaluation / スポーツ・サーフェス / 衝撃吸収 / 落錘試験 / 力学特性 / 官能評価 / 感性工学 / 頭部保護 |
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| Research Abstract |
Many requirements such as safety, lightness and comfort are necessary to helmets for sports and bike riding. Many studies regarding basic function of helmets including safety problems were reported. In the previous studies on safety problems, however, it seems to be difficult to say that those studies were accurate reviews because a helmet model integrated with a headform or a simplified helmet model different from a real one had been used in their simulations.
Therefore, the purpose of this study is clearly to make a procedure that would be a useful guidance for an optimal design of helmets by using three dimensional finite element method, which can be used to estimate the influence which helmets under impact loadings affects to human head.
FE models were made from the real shapes of the helmet and the headform used in the drop impact tests and were utilized in the simulations based on free drop conditions onto playing surfaces. And the analytical results of the headform acceleration fr
… More
om impact simulations were compared with those of experimental data. Finally, the head protection abilities of the helmet were estimated by comparing HIC(Head Injury Criterion) values from the simulation and the experiment results.
The parametric studies were done to investigate the factors that had the main effects to the headform acceleration. From this study, it could be possible to decide the required conditions of the physical parameters which are important in the optimal design of helmets under impact loading.
The results of this research are summarized as follows:
(1)Three dimensional finite element model of the helmet and the headform were constructed from the 3 dimensional measurements of the configuration of the tested helmet and the headform.
(2)It is found that the acceleration responses in the headform according to the simulation results are in good agreement with those of test results. Also the head protection abilities of the helmet are evaluated by comparing the HIC values from the headform acceleration. Especially, it is found that the HIC values from the collision onto the hemispherical anvil are smaller than those from the collision onto flat anvil in any case of drop heights.
(3)The parametric studies were conducted to investigate what factor affects the main influences to the headform acceleration. It is considered that Young's modulus of the liner is the main factor which affects to the headform acceleration. From the results of the parametric studies, it is considered that the main factors necessary to the optimal design of helmets can be determined.
(4)It is considered that the basic problems in the simulation of helmets under impact loadings are solved by this study. Further studies would be required by taking non-linearity of the materials and viscoelasticity of the liner into account. Less
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