疲劳多裂纹扩展随机模型的参数估计方法

Methods for Estimating Parameters in Random Model of Fatigue Multi Crack Propagation

建立了用试验数据估计疲劳多裂纹扩展随机模型参数的方法，尤其为利用现有的单裂纹扩展试验数据，建立了用不完全数据估计多裂纹扩展参数的方法，为含多裂纹结构的概率损伤容限分析作准备．应用最小二乘原理，讨论了完全试验数据并联远源裂纹和完全试验数据近源裂纹２种情况下裂纹扩展参数的估计方法，考虑了裂纹扩展试验的２种极限情况，给出了估计结果偏于保守的不完全试验数据近源裂纹情况下的裂纹扩展参数的估计方法．完善了疲劳多裂纹扩展随机模型，为模型的工程应用打下了基础．

Methods, which are used to evaluate correlation parameters in fatigue multi crack propagation random model using test data, were established. Taking advantage of the existed single crack propagation test data, the parameter estimation method was established by using non complete test data for analyzing the probability damage tolerance with multi crack structure.Two cases (complete test data far parallel crack and complete test data near crack) were discussed to analyze the parameter estimation method as stated above by using least square method.At the same time, the extreme cases of crack propagation test were considered.Finally, a parameter estimation method whose estimation results inclined to conservative condition in the case of non complete test data near crack was developed.