结构可靠指标的通用计算方法

在求解结构可靠指标时，保证迭代计算的收敛性是非常重要的，而实际计算表明，在有些情况下，用现有的计算方法（如JC法）进行迭代计算可能是不收敛的，这样给可靠指标的求解带来了困难。本文提出一个通用的可靠指标计算方法，通过引入可以根据迭代收敛条件自动调节的步长，实现对迭代过程和收敛性的控制。另外，本文方法不需要使用结构功能函数的偏导数，对于功能函数不能明确表达的可靠度问题尤为适用，对于功能函数可以明确表达但求导复杂的问题，可省去求导过程。最后，通过四个算例论证了本文方法的可行性。

A general approach for computing structural reliability index

To guarantee the convergence of iteration for computing reliability index is essentially a basic requirement in the most cases in formulating the iteration scheme. Unfortunately, it is not true for some current iteration scheme. A general method for computing reliability index is proposed by introducing the step lengths which will automatically self\|adjust according to the convergence condition. In addition to guarantee convergence of the iteration, this approach is especially suitable for analyzing the reliability of large scale structures and those possessing the complicit or implicit performance function because it dose not utilize gradients of the structural performance function in the iteration process. The validity of the method is illustrated through four numerical examples.