在静载和疲劳载荷作用下结构系统失效机理与可靠性分析

在结构系统使用过程中,将可能出现多种失效形式,例如静载失效或疲劳失效.根据疲劳载荷造成的累积损伤对结构极限应力的影响,给出了结构构件在基于累积损伤下的构件剩余抗力的表达式,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,并考虑了该两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,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.数值算例表明,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单元疲劳失效,这是符合结构系统使用真实情况的.

Failure mechanism and reliability analysis of structural system subjected to dead and fatigue load

Multiple failures,including dead load failure and fatigue failure,are possible in a structural system during the using process.To improve structural system reliability,residual resistance based on the understanding of passive impact of accumulated damage induced by fatigue load on ultimate stress was studied.Analysis was performed on dead load or fatigue failure of every element of a structural system and consideration was made to the relativity of two failure modes influencing reliability.Discussed was the failure mechanism of a structural system subjected to dead and fatigue load and a method of reliability analysis considering static strength and fatigue was provided.A numerical model indicates that the influence on the structural system by dead and fatigue load is different at different using states,and failure forms of elements in significant failure paths have dead and fatigue load failure.