【摘要】 混凝土作为一种多相复合材料，随机性与非线性是其基本的力学特性。为准确评估钢筋混凝土结构在强震下的性能，需对其进行非线性随机动力响应分析。然而，传统的随机振动方法（例如：虚拟激励法、路径积分法、等价线性化方法等）难以应用于大型钢筋混凝土结构的随机动力分析，而蒙特卡罗方法存在计算量大的问题。鉴于此，本文拟建立一种高效、准确的钢筋混凝土结构非线性随机动力响应分析方法。在随机损伤力学的框架内，引入两尺度随机场以描述混凝土材料的非线性和力学参数的空间变异性，采用物理随机地震动模型反映地震动的随机性，利用概率密度演化方法计算钢筋混凝土结构动力响应的概率分布。通过对一钢筋混凝土平面框架结构的非线性随机动力响应分析，证明所提方法的正确性。结果表明，混凝土材料的空间变异性对结构的非线性随机动力响应有显著影响。更多还原

【Abstract】 As a multiphase composite material, randomness and nonlinearity are the primary mechanical behaviors of concrete. To accurately evaluate the performances of reinforced concrete(RC) structures under strong earthquakes, the nonlinear stochastic dynamic response analysis of RC structures is essential. Nevertheless, stochastic dynamic analysis of RC structures with hundreds of degrees of freedom renders traditional methodologies for stochastic vibration(such as the pseudo-excitation method, the path integral technique, and the equivalent linearization method, et al.) challenging. Furthermore, Monte Carlo simulation is limited by the large computational burden. Based on the above backgrounds, an efficient method for the nonlinear stochastic dynamic response analysis of RC structures is proposed in this paper. Within the framework of stochastic damage mechanics, the two-scale random field model is adopted to describe the coupling effect of spatial variation and nonlinearity of concrete. The randomness of earthquake ground motions is represented by the physical-based stochastic ground motion model.The probability density evolution method is employed to obtain the probability distribution of dynamic responses of RC structures. A numerical example that deals with nonlinear stochastic dynamic response analysis of an RC frame structure is investigated to demonstrate the efficacy of the proposed method. The results indicate that the spatial variation of concrete has a significant influence on the dynamic responses of RC structures.更多还原