微尺度金属材料循环扭转变形行为实验研究与分析

项目名称： 微尺度金属材料循环扭转变形行为实验研究与分析

项目编号： No.11272131

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 何玉明

作者单位： 华中科技大学

项目金额： 98万元

中文摘要： 服役中的各种微构件通常因承受循环应力作用而失效, 对其循环变形行为的研究已成为力学与材料科学领域的前沿科学问题。本项目拟采用以实验研究为主数值分析为辅的研究方法，重点对微米级金属丝循环变形中的尺度效应、反常包辛格效应、循环硬化与软化以及棘轮效应进行深入研究。在实验技术方面，拟研制一套具有高灵敏度和宽量程特点的循环微扭矩传感器，在自行研制的微拉伸-微扭转实验平台上实现循环扭转功能，对10-100μm直径范围金属丝的循环变形行为进行实验研究。在数值分析方面，拟发展基于不同应变梯度塑性理论的有限元框架，采用微扭转实验确定本构模型中的内禀材料长度，对微尺度金属材料的循环变形行为进行有限元分析，对比并验证现有本构模型的有效性。课题组对循环微扭转实验已经进行了初步探索，获得了一些有价值的实验结果，如目前国内外首个细铜丝多循环扭转实验结果，这些工作为本项目的顺利开展奠定了坚实基础。

中文关键词： 循环扭转；应变梯度塑性；尺度效应；反常包辛格效应；有限元实现

英文摘要： The failure of micro-sized components in their service is usually due to cyclic loads on them, the study on their cyclic deformation behaviors has become a significant frontier problem in mechanics and material science. In the proposal program, we plan to focus on studying the size effects, abnormal Bauschinger effect, cyclic hardening or softening and ratcheting effect of micro-sized metallic wires experimentally and numerically. On the experimental side, we plan to develop a cyclic torque meter with high-sensitivity and wide measurement range for the self-developed micro-tension and micro-torsion platform. And the cyclic deformation behaviors of metal wires with diameters in the range 10-100μm will be subsequently studied with the platform. On the numerical side, we plan to develop the finite element implementations for the strain gradient plasticity theories to analyze the cyclic deformation behaviors of micro-sized metal materials, in which the intrinsic material length scales are determined by micro-torsion test. The validity of the existing constitutive relations will also be assessed by comparing with experimental results. Moreover,we have obtained some valuable experimental results in the cyclic torsion of micro-sized metal wires through initial exploration, which has laid a solid foundation for this p

英文关键词： Cyclic torsion；strain gradient plasticity；Size effect；Abnormal Bauschinger effect；Finite element implementation