中文摘要：

经典的体系可靠度分析仅涉及构件的抗弯失效,而未考虑可能发生的抗剪失效和抗扭失效等其他失效机制。为此,文中对经典的体系可靠度进一步拓展,提出考虑多重失效机制的体系可靠度问题,进而在概率密度演化理论的框架中,针对静定结构和超静定结构,分别引入等价极值事件和吸收边界条件,导出等价极值变量的密度变换解和考虑吸收边界条件的广义目标量的密度变换解。由于密度变换解的特殊形式,引入δ序列逼近的思想,获得各类密度变换解的δ序列逼近算法。最后,通过多个算例验证文中建议算法的合理性和有效性,同时指出抗剪失效机制对失效概率的贡献并不总是可以忽略,需慎重对待。

英文摘要：

Classical system reliability only focuses on the flexural failure mechanism of members,while other possible failure mechanisms,such as shear failure,torsion failure,etc.,are usually ignored.In this study,structural system reliability involving multiple failure mechanisms is put forward,and two analysis approaches based on probability density evolution theory proposed.For statically determinate structures,an equivalent extreme-value event corresponding to a failure event is derived,and transiting solution of PDF（Probability Density Function） for equivalent extreme-value variables are also obtained.For statically indeterminate structures,absorbed boundary condition is introduced into generalized density evolution equation derived together with the transiting solution of PDF.Approximation via a family of δ sequences is used to evaluate the transiting solution of PDF,and reliability can be calculated by using one-dimensional numerical integration.The accuracy and effectiveness of the proposed methods are verified through several examples.It is found from the example cases that shear failure mechanism can not be always neglected for system reliability.