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Optimization of crashworthiness of the thin shell structure composed from polycrystal metals by crystal shear banding

通过晶体剪切带优化多晶金属薄壳结构的耐撞性

基本信息

批准号：
11450041
负责人：
ITO Koichi
金额：
$ 3.01万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

For a ductile metal, localized shear banding appears as the preceding phenonemenon to the fracture. Initiation and developing of the shear band significantly influenced on the crystarograhic structure of the polycrystal materials and on loading paths. The puropose of the research project is to develop the method of optimization of crashworthiness of shock absorbing components by controlling the initiation and the developing of shear banding the obtained results are as follows.1. For FCC crystals, the mathematical model of the criterion to the initiation of shear band is established. Introducing the hypothetical 13th slip system defined by the proposed criterion into the finite element polycrystal model, numerical simulator which can be applied to the problem of weakning of crystals caused by developing of shear banding is established.2.Results of the numerical simulation and the experiment for plane strain compression of the FCC polycrystal shows that the shear banding penetrates or not according to the relative configuration of crystarographic orientation between ajacent crystal grain. The result suggests the possibily of the optimization of crashworthiness of the shock absorbing component made of polycrystal metals by controlling crystarographic texture of them.3. Numerical simulater for impact problems of a beam and of a cylindrical shell is developed. It is clarified that strain rate sensitivety of a material slightly improve the crashworthiness of a beam and a thin shell structure.

对于延性金属，局部剪切带表现为断裂的先行现象。剪切带的引发和发展对多晶材料的晶体结构和加载路径产生显着影响。本研究项目的目的是开发一种通过控制剪切带的产生和发展来优化减震部件耐撞性的方法，所得结果如下： 1．针对FCC晶体，建立了剪切带起始判据的数学模型。将所提出准则定义的假想第13滑移系引入到有限元多晶模型中，建立了适用于剪切带发展引起的晶体弱化问题的数值模拟器。2.FCC多晶的数值模拟和平面应变压缩实验结果表明，剪切带是否穿透与否取决于晶体取向的相对构型。相邻晶粒之间。结果表明，通过控制晶体织构来优化多晶金属减震部件的耐撞性是可能的。 3．开发了梁和圆柱壳冲击问题的数值模拟程序。研究表明，材料的应变率敏感性略微提高了梁和薄壳结构的耐撞性。