竖向混合结构模态阻尼比计算研究

摘要

For vertically mixed structures,the dissipated energy mechanism varies from one substructure to another,which turns the damping matrix non-proportional.Based on the complex damping theory,the equivalent modal damping ratio of vertically mixed structures was deduced.Then the feasibility of the method was testified by comparing with the experimental result of a 12-story S/RC frame.Moreover,with different damping ratios,the elastic response history analysis with finite element model was carried out.The results show that the method is simple and of high efficiency.Finally,the effect of substructures on the equivalent modal damping ratio was studied via the modal strain energy method and the presented method.%竖向混合结构因各子结构提供的能量损失机制不同，导致结构阻尼矩阵为非比例阻尼矩阵。基于复阻尼理论，推导了竖向混合结构的模态阻尼比计算公式。以一个12层竖向混合框架结构试验为例，将该方法计算得到的模态阻尼比与试验实测结果进行对比，验证了该方法的可行性；并采用不同材料阻尼比对该混合结构有限元模型进行了弹性时程分析，对该方法的有效性进行检验，结果表明该方法计算简便，效率高。最后采用该方法和模态应变能法研究了竖向混合结构各子结构自特性对整体阻尼比的影响情况。