刚度非均匀分布对可恢复功能复合结构体系动力特性的影响

Influence of nonuniform stiffness distribution on dynamic characteristics of earthquake resilient dual-systems

为分析多层结构刚度非均匀分布对可恢复功能复合结构体系动力特性的影响,在均匀刚度模型基础上提出可恢复功能复合结构体系刚度非均匀分布模型。考虑复合体系中主次体系的刚度分布特征,分别将其简化为具有特定刚度非均匀分布的剪切梁和弯曲梁,次体系底部的摇摆、自复位和耗能机制分别简化为转动弹簧和转动阻尼。通过求解特征方程得到特征值和复模态方程,分析了刚度非均匀参数、剪弯刚度比、转动刚度参数和耗能参数对体系模态周期、阻尼比、位移、位移转角和层间位移集中系数等动力特性和响应的影响规律。结果表明,当刚度非均匀分布程度较严重时,复合体系高阶模态周期、模态阻尼比和层间位移集中系数等动力特性受影响明显,但对于刚度非均匀程度中等以下的情况,可以直接采用均匀刚度模型的动力特性进行分析并进行动力响应计算,可在一定程度上简化设计过程。

To analyze the influence of nonuniform stiffness(NS)distribution of multi-story structures on the dynamic characteristics of earthquake resilient dual-systems,a NS distribution model of the system was proposed based on a uniform stiffness model.Considering the stiffness distribution characteristics of the primary and secondary subsystems,they were respectively simplified as a shear beam and a flexural beam with specific NS distribution,and the rocking,self-centering and energy dissipation mechanisms at the bottom of the secondary subsystem were respectively simplified as a rotating spring and a damping element.After obtaining eigenvalues and complex modal equations by solving the characteristic equation,the influence of the NS parameter,shear-flexural stiffness ratio,rotational stiffness parameter,and energy dissipation parameter on the dynamic characteristics of the system,such as the modal period,damping ratio,displacement,displacement angle,and interstory displacement concentration coefficient,is analyzed.It is found that when the degree of NS distribution is severe,the dynamic characteristics of the system,such as the higher-mode modal periods,modal damping ratios,and interstory displacement concentration coefficients,are significantly affected.However,when the degree of NS distribution is moderate or below,the dynamic characteristics of the uniform stiffness model can be directly used for analysis,which can simplify the design process.