CRO试样的疲劳裂纹扩展行为试验方法研究  

TESTING METHOD STUDY ON FATIGUE CRACK PROPAGATION BEHAVIOR OF CRO SPECIMEN

作　　者：赵兴华[1] 蔡力勋[1] 包陈[1] ZHAO Xing-hua CAI Li-xun BAO Chen(Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, China)

机构地区：[1]西南交通大学力学与工程学院应用力学与结构安全四川省重点实验室,四川成都610031

出　　处：《工程力学》2016年第11期20-28,共9页Engineering Mechanics

基　　金：国家自然科学基金项目(11202174;11472228);四川省青年科技创新团队项目(2013TD0004)

摘　　要：考虑到如紧凑拉伸和三点弯曲等标准试样的大尺寸要求以及高试验成本等突出问题,该文发展了含外侧径向裂纹C形环小试样(C-ring with an outer radial crack,CRO)的疲劳裂纹扩展行为试验方法。利用有限元分析建立了CRO小试样的高精度应力强度因子算式以及基于柔度法理论的裂纹长度预测公式。采用5083-H112铝合金分别完成了CRO试样和标准CT试样的疲劳裂纹扩展速率试验,获得了相应的Paris方程中的幂指数。通过对比发现,CRO和CT试样的疲劳裂纹扩展规律基本一致,验证了新方法的有效性。基于上述方法对C250钢两种厚度CRO试样的疲劳裂纹扩展行为进行了应用研究。Recognizing the large size requirement and high cost associated with the test of the standard specimens such as compact tension（CT） and single edged notched bending（SEB） specimen, a testing method for fatigue crack propagation of small size C-ring specimen with an outer radial crack（CRO） has been developed. With finite element analyses, expressions of stress intensity factor and crack length based on compliance principle were established with good accuracy. A type of 5083-H112 aluminum alloy was employed to complete the tests of fatigue crack growth rate by using CRO and CT specimens, respectively. Correspondingly, the power exponent of Paris equation of the two types of specimens were also obtained. The comparison shows that the fatigue crack propagation behaviors of CRO and CT specimens are similar, implying that the new method is valid and effective. Based on the above method, the fatigue crack propagation of two CRO samples of C250 steel with different thicknesses has been studied.

关 键 词：固体力学 疲劳裂纹扩展 柔度法 CRO试样 5083-H112铝合金 C250马氏体钢 

分 类 号：TB302[一般工业技术—材料科学与工程]