随机载荷作用下平台结构疲劳寿命预测

海洋等工程结构物在服役过程中的受载历程是一个随机过程。研究裂纹在谱载荷作用下的扩展规律对可靠预报平台等结构物的疲劳寿命具有十分重要的意义。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,来考查载荷相互作用下疲劳裂纹扩展寿命的计算模型。用该模型对几种谱载荷作用下疲劳实验结果进行了预测,将预测结果与不考虑裂纹闭合的线性损伤模型及疲劳计算程序FASTRAN的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 loadings is very important for the reliable life prediction of ship structures. In this paper, 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, has been proposed. Fatigue crack growth under different spectrum loadings has been predicted by the present model. The predicted results are compared with test data, and those predicted by FASTRN codes, and the results show that the predicted results are in good agreement with the test data.