结构四阶矩可靠度计算的分步迭代法

A Step Iterative Algorithm in Structural Fourth-Moment Reliability Calculation

在结构四阶矩可靠度理论中，较为关键的一步是求解由最大熵原理确定的功能函数随机变量概率分布密度的待定参数，这需要求解由无穷积分表示的五元非线性方程组，解这种方程组较为有效的方法是线性迭代法，但计算中选择合适的初始点相当困难，因为找不到合适的初始点而使计算不能收敛。本文提出一种可行的办法，圆满地解决了这一问题，从而为四阶矩可靠度方法的应用创造了条件。

In structural fourth-moment reliability theory, it is a critical step to determine the parameters of probability density function for random variable of safety marginz which is evaluated by the maximum entropy theory. To do so, a set of nonliear infinite integral equations must be solved. An efficient procedure is the hear iterative algorithm, but for calculation converge the selection of initial values is very difficult. For this purpose, a feasible algorithm is presented, it makes the problem to be solved perfectly and provide favourable factors for application of fourth-moment reliability method.