静载和疲劳载荷共同作用下的结构可靠性分析

Structural Reliability Analysis Under Dead Load and Fatigue Load

对在静载荷和疲劳载荷共同作用下的结构系统中的各失效元件的失效时间进行研究。首先,分析了失效路径中第一个失效元件的静载失效和疲劳失效时间,建立了两种失效时间下的安全余量方程,分别计算两种失效模式下的可靠性指标。通过对比两个可靠性指标的大小,得出了第一个元件的失效模式和失效时间。其次,在第一个失效元件失效时间的基础上,分析了失效路径中未失效元件的剩余强度和累积损伤,从而得出了失效路径中各元件的失效时间,为建立安全余量方程提供了合理的表达式。通过算例表明,本文方法符合工程实际,为在静载荷和疲劳载荷共同作用下的结构系统的可靠性分析提供了一个合理的方法。

The failure time of elements in structural system under dead load and fatigue load was studied. The dead load failure time and the fatigue failure time of the first failure element in failure routes were analyzed, and the equations of safety margin under the two failure times were established, the reliability indexes under the two failure modes were calculated separately. Comparing the two reliability indexes, we obtained the failure mode and the failure time of the first failure element. Based on the failure time of the first failure element, the residual strength and the cumulative damage of the non-failure elements were analyzed, thus, the failure times of elements in failure routes were obtained, the reasonable expression were provided for the establishment of the equation of safety margin. By the example it can be seen that the proposed method coincides with the engineering fact and is suitable for reliability analysis of a structural system under dead load and fatigue load at the same time.