非高斯随机激励下工程结构可靠性估计的一种方法

本文将工程结构考虑为振动系统,把随机载荷及在结构上的载荷效应作为随机过程,分析状态函数的高阶矩,进行最大熵概率分析,得到结构在随机载荷作用下失效的概率。此法为随机环境下工作的结构、构件或设备的安全设计、可靠性检验提供了一个可行的方法。

A Reliability Estimation Method of Engineering Structures under Non-Gauss Random Excitation

A structural reliability analysis method is proposed by treating the engineering structure under random load as a vibration system. Actual engineering structures, such as craft, vehicles and ocean platforms are vibration systems under random loads, most of which are non-Gauss distributed. The response of a structure under random load is random vibration, while the load and its effect should be described as random processes. Load effect (such as displacement, stress, strain etc.)relates not only to the amplitude of the load but also to the frequency distribution of the load and natural vibration charactristics of the structure (such as natural frequency, damping etc.)The structure will be damaged if load exceeds a certain limit, hence the reliability of a structure is related to its vibration characteristics.The reliability of the structure under non-Gauss stable random load is analysed by regarding the structure as a vibration system, load and its effect as random processes. Based on the state function, fre- quency response function of the sructure and the spectra of the non-Guass load, high order moments of the state function are calculated, from which the analytic probpability density function of state function is derived by using the maximum entropy probability analysis method, therefore the failure probability of the structure under non-Guass random load is obtained. The method gives out a feasible way of the safety design and reliability inspection of structures, equipments and elements working in random circumstances. A simple example is demonstrated to indicate the relation between the failure probability and the vibration characteristics of structures.