【摘要】 介绍了自适应重要抽样方法的基本原理,定义了均值敏感性因子和标准差敏感性因子.最后采用算例验证了自适应重要抽样方法分析钢闸门系统可靠度敏感性的有效性.由分析可得以下结论,当不考虑抗力间的相关性时,荷载、受剪破坏抗力和弯剪复合破坏抗力的敏感性因子最大.当考虑抗力间的相关性后,受弯破坏抗力、受剪破坏抗力、弯剪复合破坏抗力的敏感性因子都随抗力间相关系数的增大而明显增大,但是抗力间的相关性对上下翼缘厚度、面板厚度和腹板厚度的敏感性因子基本没有影响.抗力间相关性越高,3种失效模式抗力的敏感性因子间的差别越小.变量的均值敏感性因子和标准差敏感性因子是高度相关的,都可以用来识别最敏感的随机变量.更多还原

【Abstract】 This paper aims to evaluate the system reliability sensitivity of main beams using the adaptive importance sampling method.Firstly,the adaptive importance sampling method is introduced.Then,the mean sensitivity coefficient and the standard deviation sensitivity coefficient are formulated.Finally,an illustrative example is given to demonstrate the validity of the adaptive importance sampling method.The results indicate that,if the correlations between resistances associated with different failure modes are not taken into account,hydrostatic load acting on hydraulic gates,resistance associated with bending failure mode,and resistance associated with combination of bending and shear failure modes are significant random variables with higher sensitivity coefficients.While the correlations between resistances associated with different failure modes are not considered,the sensitivity coefficients of resistances associated with three failure modes significantly increase with increasing correlation coefficients between resistances.But the sensitivity coefficients for thickness of the flange,thickness of skin plate,thickness of the web are almost not influenced by the correlation coefficients between resistances.The mean sensitivity coefficient and the standard deviation sensitivity coefficient are strongly related and both can be used to identify key contributing random variables.更多还原