综合考虑随机结构系统静强度和疲劳的失效机理与可靠性分析

 根据疲劳载荷造成的随机裂纹对结构极限应力和截面模量的影响,给出了结构构件在裂纹扩展下的构件剩余抗力的表达形式,分析了结构系统中每一个单元在静载和疲劳载荷作用下的失效形式,并考虑了各失效模式之间的相关性对该单元可靠性的影响。具体分析了结构系统在静载和疲劳载荷作用下的失效机理以及各失效模式之间的相关性,给出了在静载和疲劳载荷作用下结构系统的可靠性分析方法。结合数值算例对结构系统同时进行了静强度和疲劳的可靠性分析,表明在不同的使用年限内,静载和疲劳载荷对结构系统可靠性的影响是不同的;在结构系统主要失效路径中既有单元静强度失效又有疲劳失效,这是符合结构系统使用真实情况的。

Failure Mechanism and Reliability Analysis of Stochastic Structural System Considering Static Strength and Fatigue

Based on the understanding of passive impact of crack induced by fatigue load on ultimate stress and section module,the paper gives the expression of residual resistance,analyzes the dead or fatigue load failure of every element of structural system and considers the relativity of every failure modes influencing on the element reliability.The paper discusses the failure mechanism of structural system subjected to dead and fatigue load and gives the method of reliability analysis considering static strength and fatigue.A numerical example is analyzed.It is indicated that the influence on the structural system by dead and fatigue load is different at different application states.The failure forms of elements in the significant failure paths have dead and fatigue load failure.It is suitable for engineering case.