材料统计特性对裂纹扩展规律的影响

从材质的不均匀分布是疲劳裂纹扩展速率变动的主要内在这一观点出发，将材料特性沿着裂纹扩展路径的变化处理为一个随机过程，讨论了几组相关长度对材料特性的自相关函数与其计算区间大小之间关系的影响，通过实验验证，给出了材料对裂纹扩展的阻力系数Ｚ（Ｘ）的自相关函数及其概率分布函数，并对裂纹扩展速率表达式中有关参数进行了分析，探讨了利用较大尺寸的裂纹扩展实验数据来推导短裂纹扩展规律的可能性。

EFFECT OF STATISTIC PROPERTIES OF MATERIAL ON CRCK GROWTH

in this paper, the material property is treated as a spatial random process along the path of the fatigue crack. The relation between the measured autocorrelation funCtions and averaging length is discussed for several correlation lengths.APplying the previously proposed method, the experimental data from stress-intensity-factor -controlled fatigue crack growth tests are analyses for different averaging lengths to detenmine the autocorrelation functions and probability distributions of parameters in the crack growth rate law.So far as the present experiment is concerned,it can be concluded from these observations that a very small extension of a short crack can be predicted using the data obtained from measurements on rather large scale fatigue crack growth.