机械结构可靠性灵敏度分析的鞍点估计方法

将鞍点估计理论与可靠性灵敏度理论结合,提出了一种结构可靠性灵敏度分析的鞍点估计方法,以实现机械结构的可靠性灵敏度设计.通过利用鞍点估计技术能无限逼近非正态变量空间中线性极限状态函数概率分布的特点,获取外载荷作用下机械结构响应的概率密度函数和分布函数.在此基础上,针对存在不确定因素的基本参数进行可靠性分析,推导出了基于鞍点估计的可靠性灵敏度公式,研究了机械结构可靠性灵敏度设计方法.并将其引入到新型旋转式立体车库载车台主梁结构的可靠性灵敏度分析实例中,与改进一次二阶矩方法（FOSM）计算所得的结果对比验证了该方法的可行性和有效性.

Saddlepoint approximation method for mechanical structural reliability sensitivity analysis

Aiming at realizing machine structural reliability sensitivity design,saddlepoint approximation method for machine structural reliability sensitivity analysis is proposed via combining the saddlepoint approximation theory with the reliability sensitivity analysis method theory.Probability density function and probability distribution function of stochastic structure response under the action of external loads were obtained by using the feature which the saddlepoint approximation can directly estimate probability distribution of linear limit state function in non-normal variables space.For solving reliability analysis problem with the basic parameters of uncertainty,and the reliability sensitivity formula based on the saddlepoint approximation theory was derived systematically and reliability sensitivity of machine components with random parameters was studied.The proposed approach was introduced into reliability sensitivity analysis of the loading platform of the rotating stereo garage main beam structure.According to the result compared with that obtained by improved FOSM method,the result shows that the proposed approach is feasible and effective.