两种结构非概率可靠性指标的比较研究

Comparsion Analysis on the Two Structural Non-probabilistic Reliability Indices

结构非概率可靠性模型通常采用非概率可靠性指标来度量可靠性。文中对结构非概率可靠性指标的两种定义,即结构功能函数的均值与离差之比及标准化区间变量空间原点到失效面的最短距离进行了研究。研究结果表明:1)当结构功能函数为线性函数时,两种定义具有一致性。2)当结构功能函数为非线性函数时,前者度量结构可靠性存在一定偏差,而后者可以准确度量结构可靠性。3)前者依赖于结构功能函数的表达形式,而后者则与结构功能函数的表达形式无关。实例分析验证了文中结论。

In structural non-probabilistic reliability model, structure reliability is typically measured by non-proba- bilistic reliability index. In this paper, two definitions of structural non-probabilistic reliability index are investiga- ted, which are the ratio of mean value to deviation of structural performance function and the minimum distance from the origin to the failure surface in normal interval variables space. The results show that： 1 ） when the struc- tural function is a linear function, the consistency of the two definitions is proved. 2） when the structure function is a nonlinear function, there are slight deviation in measuring structural reliability using the former definition, where- as no deviation using the latter one. 3 ） the former definition depends on the expression form of structural perform- ance function, but the latter one does not. The conclusions are verified by two examples.