非线性较强安全余量方程可靠性指标精确计算方法研究

为了得到非线性较强安全余量方程的可靠性指标的较为精确解,在验算点法和中心点法的基础上,提出了一种类似于并联结构联合失效概率的方法--联合法,进行可靠性分析.将安全余量在计算所得到的2点进行Taylor展开,使展开后所得到的失效区与实际失效区尽可能的吻合,减小误差,提高了对于安全余量方程在设计验算点处非线性较强的结构可靠性指标的计算精度.通过算例表明,该分析方法较精确地得到了可靠性指标,且计算过程简单易懂.

Accurate calculation for reliability index of high nonlinear safety margin equation

In order to obtain a more precise reliability index with the highly nonlinear safety margin equation, a new method is proposed to perform reliability analysis on the basis of H-L and FOSM. This is similar to the method for joint failure probabilities of parallel structures. With this method, the safety margin was calculated for a Taylor expansion. Using two examples of structural failure, the failure area derived from calculations matched the actual failure area with little deviation. Using this formula, the calculation accuracy of the structural reliability index increases when the safety margin equation is highly non-linear. Examples show that a more accurate reliability index can be obtained with the proposed method and the calculation procedure is easy to understand.