【摘要】 推导出线性随机结构在平稳随机激励下的复合随机振动传递的理论公式,建立了激励统计特性、随机结构特性以及响应统计特性三者之间的关系.理论分析表明,复合随机振动传递规律产生的变异主要取决于系统频响函数的变异程度.采用Monte Carlo方法,引入响应均值放大系数、响应方差放大系数及响应自谱放大函数的概念,对单自由度线性随机系统的复合随机振动传递规律的变异性进行了定量分析.结果表明,随着结构参数变异系数δ的增大,响应自谱放大函数的均值曲线峰值迅速减小,曲线形状变“矮、胖”,在δ=5%变异下,相对均值系统的自谱放大函数的峰值减小已超过45%;而响应均值放大系数和响应方差放大系数均单调增加,在δ≤5%时增加的幅度都很有限,且均与质量变异无关.更多还原

【Abstract】 The theoretical formulas of combined random vibration transferring were deduced on linear random structure at stationary random excitation.The relationships among statistical character of excitation,random structure character and response statistical character were established.Results showed the variation of transfer rule of combined random variation mainly depended on the degree of variance of frequency response function.And,the conceptions on amplification coefficient of response mean,amplification coefficient of response variance and amplification function of response auto-power density spectrum were presented,the variation of transfer rule of combined random vibration was analyzed quantitatively on SDOF linear stochastic system by used of Monte-Carlo method.The numerical simulation results indicated that,with the increment of structural parameter variation coefficient δ,the peak value of curve on amplification function of response auto-power spectrum density reduced fast and the curve turned short and fat.In the variation condition at,the peak value of amplification function of auto-power spectrum density had made a more than 45% reduction compared with that of mean system.However,both amplification coefficient of response mean and amplification coefficient of response variance were monotone increasing,enhanced amplitudes were finitude when δ≤5% and independency with mass variation.更多还原