结构可靠性分析的多平面组合近似方法研究

Study of multiple plane combination approximate method for structural reliability analysis

应用AFOSM法获得最大可能概率失效点和最大可能失效区域,对最大可能失效区域边界进行了近似界定。采用超单位超球坐标构造搜索方向,利用黄金分割法快速求得线性化点,提出一种新的多近似平面的构造方法,避免了构造近似平面的盲目性和无序性。针对多近似平面组成系统的特性,提出基于AFOSM的逐次等效主近似平面方法计算结构的失效概率。算例结果表明,本方法可行有效且效率高,是一种精度较高的结构可靠性近似分析方法。

Based on the most probable failure point and the most probable failure domain obtained by AFOSM,an approximate border limit of the most probable failure domain is presented. One dimension search directions are generated by unit hyperspherical coordinates. To build approximation planes golden section algorithm is used to determine quickly the linearization points. A new multiple planes combina- tion method is proposed to circumvent the disorder and blindness. Acorrding to the features of syetem consisted of approximate planes, an equivalent main approximate plane method is developed to estimate the structural failure probability based AFOSM. Finally,the number examples are provided to illustrate the feasibility and validity of the proposed method with acceptable accuracy and efficiency.