随机结构分析中的均值参数反应与反应均值

在结构分析中考虑力学参数的随机性时，均值参数系统反应往往不能反映结构反应均值。本文通过静力与动力典型例证的分析说明，对于具有随机参数的结构，在静力情况下，仅对于极为特殊的概率分布，结构均值参数系统反应才等于结构反应均值，但在一般情况下，随着结构力学参数变异性的增大，均值参数系统反应与结构反应均值的差异显著增大。而在动力情况下二者的相对误差则远比静力情况为大，并且对激励的频谱和结构固有频率的相对关系相当敏感。因此，以结构均值参数为标的确定性结构分析，其结果可能与现实工程结构的反应均值相去甚远，故而采用随机结构模型是必要的。

Mean Response Considering Random Structural Properties in Stochastic Structural Analysis

If the randomness of the properties is considered in the structural analysis, the response evaluated with mean properties couldn't reflect the mean response. In the present paper, two typical examples were presented to illustrate that for structures with random parameters, under static loading for some special probability distribution the response of structures with mean parameters is equal to the mean response of the structures. But in general situation with variation of parameters increasing, the discrepancy between response of structure with mean parameters and the mean response of the structures enlarges greatly. While in dynamic situation, the relative errors between the two quantities are far greater than that in static situation, moreover, they are sensitive to the relative relationship between the frequency spectra and the frequency of the structure. Thus, the result of deterministic structural analysis based on mean parameters may be greatly different from the response of the realistic engineering structures. Therefore, it is necessary to employ the stochastic structural model.