由于加工、制造等原因，实际结构系统往往所具有很多不确定性，准确评估随机系统的动力学行为不仅具有实际意义，而且是近年来结构动力学理论的一个研究热点。本文研究了同时考虑结构模型参数与所受外激励载荷具有不确定性的复合随机振动问题。结构模型参数的不确定性采用随机变量模拟，外激励载荷的不确定性采用随机过程模拟，提出了结构随机振动响应评估的混合混沌多项式－虚拟激励（PC-PEM）方法。数值算例研究了参数不确定性在21杆桁架中的传播，讨论了响应的一阶、二阶统计矩，并同蒙特卡洛方法进行对比表明提出方法的正确性和有效性。本文的工作对于考虑不确定的复杂装备与结构系统的随机振动分析具有很好的借鉴意义。%Due to processing and manufacturing reasons,an actual structure system often has a lot of uncertainties. How to correctly assess dynamic behavior of an uncertain system not only has a practical significance,but also is a hot topic of structural dynamics theory in recent years.Here,the dynamic behavior of a structure with uncertain parameters under external random excitation was investigated.The uncertain parameters of the structure were taken as random variables,and the random excitations were taken as stochastic processes.The hybrid polynomial chaos and pseudo excitation method (PC-PEM)was proposed to evaluate the random vibration response of the uncertain structure.Finally, the proposed method was applied to evaluate the random response of a 21-bar truss with uncertain parameters.The first two orders statistical moments of its random response were discussed,and the correctness and effectiveness of the proposed method were verified by comparing the results of this method with those of Monte Carlo method.This study was of great significance for random vibration analysis of complex equipments and structures with uncertain parameters.
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