MDOF系统构件地震能量反应研究

Research on component-based seismic energy response of MDOF system

基于有限元理论推导结构能量方程,提出构件能量反应的不平衡性。在地震动作用下,由于能量的往复传递,结构内部任何构件的能量反应几乎时刻均是不平衡的。构件的弹性行为是能量在构件间传递的途径和保障,而其塑性行为则是能量得以耗散的原因,据此定义吸能及耗能构件。通过不同场地条件记录、对不同剪切型多自由度体系展开的弹塑性时程反应统计分析,研究构件能量反应分布及传递特征。结果表明:刚度分布对结构耗能分布影响最大,即便是等屈服强度系数分布模型,底层最薄弱,耗能也最集中;构件的吸能及耗能特征与构件质量、结构刚度的分布关系密切,而滞回模型的选取及不同场地条件下的记录输入对构件能量反应分布的影响不大。

Structure＇s energy equation was derived based on finite element method, with the component-based energy imbalance energy proposed. As energy transfers constantly under earthquake excitation, almost at any time any structural component has imbalanced energy response. The component＇s elasticity ensures energy＇s transferring while its plasticity renders energy＇s dissipation, thus, the energy-producing and the energy-absorbing components were defined conceptually. Statistical analyses of the component-based energy＇s distribution and energy＇s transferring were carried out on the layered shear muhi-degree of freedom （ abbr. MDOF） system with its properties and input record＇s site condition considered. The results show that： stiffness＇ distribution of the MDOF system has the greatest influence on its energy distribution, and the bottom layer is the weakest where energy concentration happens, even to the equal yield strength coefficient model; component＇s character of energy-producing or energy-absorbing highly depends on the component＇s mass and system＇s stiffness distribution, while selection of the hysteretic model and the input record＇s site condition has little influence.