行波地震激励下采用位移输入模式的随机振动分析方法  

RANDOM VIBRATION ANALYSIS METHOD IN DISPLACEMENT INPUT MODEL UNDER TRAVELING WAVE EARTHQUAKE EXCITATIONS

作　　者：李永华[1] 桂国庆[2,1] 李思明[3] 

机构地区：[1]南昌大学建筑工程学院,江西南昌330029 [2]井冈山大学建筑工程学院,江西吉安343009 [3]同济大学土木工程学院,上海200092

出　　处：《工程力学》2012年第2期45-51,共7页Engineering Mechanics

摘　　要：在行波地震激励分析时，传统的随机振动虚拟激励法需将结构内部节点绝对位移分解成拟静力位移和动态相对位移两部分，分别对其构造虚拟激励进行两次求解，且在构造虚拟激励过程中需提取结构内部节点质量、刚度矩阵，当整体结构自由度数较大时这一过程相当繁琐。该文提出了一种位移输入模式的随机振动虚拟激励法，该方法采用位移输入模式来构造虚拟激励，直接对结构绝对位移进行一次性求解，与传统虚拟激励法相比，该方法在构造虚拟激励过程中只需提取内部节点与支座节点间的耦合刚度矩阵，更为方便实用。此外，分析了位移输入模式由于阻尼忽略项的不同可能对结构底部单元造成的计算结果误差，并提出了相应的解决方法。In traveling-wave excitation analysis, the free nodal absolute displacements are decomposed into pseudo-static and dynamic parts respectively in conventional pseudo excitation method （PEM） of random vibration, and the mass and stiffness matrices of free nodes must be obtained for constructing pseudo acceleration and displacement harmonic excitation, which is very time-consuming especially for solving problems with many degrees of freedom. A new PEM is presented here, in which the free nodal absolute displacements can be solved directly in displacement input model. As only coupled stiffness matrices between free and restrained nodes is needed for constructing pseudo excitation, it is more convenient to use in engineering than conventional PEM. The error of the calculation results of basement elements in adopting the displacement input modeldue to the different omitted damping terms is analyzed, and an effective method is presented to solve the problem.

关 键 词：行波激励 随机振动 虚拟激励法 位移输入模式 绝对位移 

分 类 号：TU311.3[建筑科学—结构工程]