非线性随机系统的独立失效模式可靠性灵敏度

较好地解决了具有独立失效模式的多自由度非线性随机参数振动系统的可靠性灵敏度分析问题．应用四阶矩技术和Edgeworth级数把未知的响应和状态函数的概率分布展开成标准的正态分布的表达式，从而确定了系统的可靠度和可靠性灵敏度，并放松了随机参数的分布概型和激励类型．

SENSITIVITY OF RELIABILITY IN NONLINEAR RANDOM SYSTEMS WITH INDEPENDENT FAILURE MODES

The study of sensitivity of reliability in random systems is important for design purposes. The sensitivity analysis of reliability may help the designer to establish acceptable tolerances on structural system. Parameter uncertainty is inherent in most engineering problems, and its effects on structural reliability and its sensitivity should be assessed. A set of useful sensitivity analysis in vibration reliability has practical applications within reliability-based design, in optimization of structural design, construction, maintenance and inspection under reliability constraints, in parameter studies of reliability, and in reliability updating. In the present work, details of a numerical solution to the sensitivity of reliability for the multi-degree-of-freedom nonlinear vibrations with random parameters and independent failure modes are given. First four moments of the response and the state function are obtained using statistical fourth moment method. Unknown distribution function of random state function is approximately determined by the standard normal distribution functions using Edgeworth series technique. The reliability and reliability sensitivity function of nonlinear vibrations are studied. On the condition of known first four moments of original random variables, the method can modify demands to the distribution function of random parameters and the excitation forms and measure the reliability and its sensitivity of nonlinear random vibrations in practical engineering.