基于延性材料RVE破断行为的结构完整性评价基础问题研究

项目名称： 基于延性材料RVE破断行为的结构完整性评价基础问题研究

项目编号： No.11472228

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 蔡力勋

作者单位： 西南交通大学

项目金额： 86万元

中文摘要： 核电、化工、石油工程中的压力容器、管道等重大装备在服役过程中不可避免地存在某些缺陷，对含缺陷结构进行完整性评价是确保装备安全稳定运行的重要技术手段，其工程意义和经济价值突出。国际上已形成具有不同评价等级的各类完整性评价规范，在关乎效益最大化的高等级评价方法中，包括延性材料单轴本构关系、含裂纹结构的准静态与疲劳断裂行为预测等基础性问题尚未有效解决。为此，本项目拟研究获取延性材料RVE（Representative Volume Element）直至破坏的全程单轴本构关系的方法，并研究材料在拉扭复杂加载条件下的临界破坏机制，发展结构裂纹准静态启裂与扩展的理论预测方法；开展延性材料RVE含大变形循环破坏的低周疲劳行为研究，通过在结构裂纹尖端塑性区引入低循环损伤来建立描述含裂纹结构的疲劳裂纹扩展行为的理论方法。预计成果将为含缺陷结构的完整性高等级评价方法提供理论基础和技术支撑，具有重要的应用前景。

中文关键词： 结构完整性；疲劳与断裂；失效机理；全程本构关系；延性材料RVE

英文摘要： Many defects can be inevitably found in the pressure vessels and pipelines which are commonly applied in the nuclear power, chemical industry and petroleum engineering. The integrity assessment of the structures containing defects is an important technique to ensure the safe operation of equipments, which shows remarkable benefit and economic value in the engineering application. Nowadays, some kinds of integrity assessment specifications have been issued for enforcement by different organizations. In the high-grading methods of integrity assessment relating to the efficiency maximization, some fundamental problems, such as uniaxial constitutive relationships of ductile materials, the prediction of quasistatic and fatigue fracture behaviors of cracked structures, still have not been solved. Therefore, this project plans to investigate the method for the full range uniaxial constitutive relationships up to failure of RVE (representative volume element) for ductile materials, reveal the critical failure mechanism of material under complicated tension and torsion loading, develop the theoretical forecasting methods for the quasistatic crack initiation and propagation of structural cracks, research the low cycle fatigue behaviors containing large deforming cyclic breakage of RVE for ductile materials, construct the theoretical method for predicting the fatigue crack propagation behaviors of cracked structures by introducing low cycle damage into the description of plastic zone near the crack tip. The expected achievements will provide the theoretical basis and technical supports on the high-grading integrity assessment methods for structures containing defects, which has widely engineering application prospects.

英文关键词： structure integrity;fatigue and fracture;failure mechanism;full range constitutive relationship;ductile material RVE