基于参数α=2的Gegenbauer正交多项式展开方法,研究了大变异系数情况下复合随机强Duffing体系的可靠性分析问题.应用随机空间的正交多项式展开方法,Edgeworth级数逼近技术求取了强非线性随机振动系统响应的前四阶矩以及概率密度函数.基于首次超越模型,讨论了复合随机强Duffing体系的可靠性分析问题.提出了系统动态可靠度与系统平均可靠度的区别、联系以及各自特点,发展了可靠度数值计算公式.分析计算结果与Monte-Carlo模拟结果较好符合,表明该方法的正确与有效.
By using of Gegenbauer orthogonal polynomials, an effective numerical method for the reliability analysis of double random Duffing system with large coefficient of variation is presented. On the basis of the first passage model, the fourth-moment technique, the Edgeworth series approximation theory and the orthogonal polynomial expansion method are employed to develop a reliability analysis method systematically. The dynamic reliability and mean reliability of the system is discussed. The results obtained by this method are verified by Monte-Carlo simulations.