铅剪切阻尼器的阻尼力模型与设计

基于理想弹塑性本构关系,推导了铅剪切阻尼器的两个阻尼力模型.根据能量原理,考虑剪切变形均匀性假设,横截面各点剪应力同时屈服,得到了均匀变形阻尼力模型(均匀模型).依据剪应力分布规律和变形连续性条件,引进一个剪应变分布函数,用来描述剪切屈服后剪应变随屈服区扩展的变化规律,通过横截面剪力平衡方程,确定了非均匀变形阻尼力模型(非均匀模型).两个理论模型的滞回曲线与Robinson SeismicLtd公司的实验曲线进行比较.结果表明,小位移时非均匀模型能精确模拟实验曲线,而均匀模型的计算结果明显大于实验数据;大位移时二者均与实验曲线吻合较好.证明了非均匀模型的极限阻尼力是均匀模型的最大阻尼力(屈服剪力).以极限阻尼力和屈服位移为参数,给出了阻尼器的设计方法.

DAMPING FORCE MODELS AND DESIGNS OF LEAD SHEAR DAMPERS

Based on the elasto-perfectly plastic constitutive relation, two damping force models of lead shear dampers are deduced. Considering the assumption of the shear deformation equality and the simultaneous yield of the shear stress in the cross section, the equal deformation damping force model (equal model) is derived from the energy principle. One shear strain distribution function is introduced to describe the relation between the shear strain associated with the shear yield and the yield extent in the cross section based on the shear stress distribution and the deformation continuity. From the shear force balance equation in the cross section, the unequal deformation damping force model (unequal model) is formulated. Comparing two theoretical hysteretic loops with the experimental data obtained from Robinson Seismic Ltd, results indicate that the unequal model can accurately predict the experimental curves in both small and large displacements, while the equal model can approximately coincide with the experimental data in big displacements only. Consequently, the limit damping force of the unequal model proves the peak damping force (yield shear force) of the equal model. A proposed method is presented to design lead shear dampers according to the limit damping forces and yield displacements.