基于重要抽样法的耐压球壳可靠性计算方法研究

Reliability Calculation Method of Pressure Resistant Spherical Shell Based on Importance Sampling Method

目的 解决耐压球壳极小失效概率的可靠性计算问题。方法 在自适应Kriging的基础上,结合重要抽样法提出耐压球壳可靠性计算方法。该方法在较大失效概率下构建的Kriging模型基础上获得重要方向,在重要方向上计算得到较低失效概率下的设计点,以设计点为中心,构建小失效概率的Kriging模型,并通过此模型采用重要抽样法开展可靠性计算。结果 分别使用提出的重要抽样法和蒙特卡洛法计算了2个算例的失效概率,计算结果表明,该方法具有较高的精度和效率。使用该方法对某耐压球壳工作载荷下的失效概率进行了计算,计算得到该球壳失效概率为4.094×10^(–96)。结论 研究结果可为无失效方程下极低失效概率的可靠性计算问题提供参考。

The work aims to solve the reliability calculation problem of pressure resistant spherical shells with minimal failure probability.Based on adaptive Kriging,a reliability calculation method of pressure resistant spherical shells was proposed in combination with the importance sampling method.This method mainly included obtaining important direction based on the building Kriging model of high failure probability,computing design points of the model of low failure probability,building a Kriging model of low failure probability centered on the design point,and using this model to carry out reliability calculation with the importance sampling method.The failure probability of two examples was calculated with the importance sampling method proposed in this paper and the Monte Carlo method.The calculation results showed that the method proposed in this paper had high calculation accuracy and efficiency.The method was also used to calculate the failure probability of a pressure resistant spherical shell under working load,and the failure probability was 4.094×10^(–96).The research can provide reference for reliability calculation of extremely low failure probability without failure equation.