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针对工程中截尾概率变量与非概率变量同时存在的情况,给出一种新的截尾概率与非概率混合可靠性模型。在该混合可靠性模型基础上,按照可靠性指标(RIA)法给出双层嵌套可靠性优化模型,并采用改进搜索策略后的ST-Powell优化算法在外层搜索设计变量的最优值,内层采用能保证收敛的改进的有限步长迭代法求解混合可靠性指标。数值算例表明,改进搜索策略后的ST-Powell优化算法的全局寻优性得到显著提升;改进搜索策略后的ST-Powell优化算法与改进的有限步长迭代法相结合求解双层嵌套混合可靠性优化模型的正确性得到验证,且对于非线性程度较高的极限状态函数同样能够得到满足截尾概率与非概率混合可靠性模型指标要求的最优解,并对工程结构算例具有很好的适应性。
Aiming at the co-existence of truncated probability variable and non-probability variable in engineering, a new truncated probability and non-probabilistic mixed reliability model is given. Based on the hybrid reliability model, the two-level nested reliability optimization model is given according to the reliability index (RIA) method. The optimal value of the design variables is searched by the ST-Powell optimization algorithm after the improved search strategy, The inner iterative method is used to solve the mixed reliability index with an improved finite-step iterative method that guarantees convergence. Numerical examples show that the global optimization of ST-Powell optimization algorithm with improved search strategy is significantly improved. Combining the improved ST-Powell optimization algorithm and the improved finite-step iteration method, the two-level nested hybrid reliability The correctness of the sexual optimization model is verified, and for the limit state function with higher nonlinearity, the optimal solution that meets the requirements of the truncated probability and non-probabilistic mixed reliability model index can also be obtained and has a good example for the engineering structure example Adaptability.