随机载荷作用下船舶结构疲劳裂纹扩展

基于船舶等工程结构物在服役过程中的受载历程是一个随机过程,提出了一个由应力比和裂纹尖端约束及塑性区尺寸为主要参数计算裂纹张开比来考虑载荷相互作用的疲劳裂纹扩展寿命计算模型.用该模型对几种谱载荷作用下疲劳实验结果进行了预测.预测结果和不考虑裂纹闭合的线性损伤模型及疲劳计算程序FASTRAN预测结果进行了比较,表明本模型能较好地预测谱载荷作用下的疲劳裂纹扩展.

Fatigue Crack Growth of Ship Structures under Random Loading

Engineering structures,such as ship structures,are subjected to random loading in service.Studying of fatigue crack growth under different spectrum loading is very important for the reliable life prediction of ship structures.A fatigue life prediction model considering the interaction of loading sequence,taking stress ratio and the plastic zone size near crack tip as main parameters in calculation of the crack opening ratio,was proposed.The fatigue crack growth under different spectrum loadings was predicted by the present model.The predicted results were compared with the test data,and these of predicted by FASTRAN codes,the results show that the predicted results are in good agreement with the test data.