斜向三维隔震支座的非线性力学性能试验及数值模拟研究

该文针对三维隔震结构较高竖向承载力和减震效果的需求，基于铅芯橡胶支座提出了斜向三维隔震支座，并基于铅芯橡胶支座的非线性力学本构模型，建立了考虑压缩应力及刚度衰减影响的三维隔震支座非线性竖向刚度计算模型。进行了倾斜角度分别为12°和15°的三维隔震支座模型力学性能试验，试验结果得到了该三维隔震支座滞回模型呈现出加载和卸载非平行特征，竖向刚度呈现非线性变化，以及角度和竖向位移对力学性能的影响规律。进一步对理论与试验结果进行对比分析，三维隔震支座的试验结果与理论计算值吻合。最后利用通用有限元软件建立不同倾斜角度的三维隔震支座数值分析模型，基于计算理论、静力试验及数值仿真结果分析了摩擦系数、剪应变、倾斜角度对三维隔震支座非线性竖向刚度的影响。

EXPERIMENTAL AND NUMERICAL STUDY ON THE NONLINEAR MECHANICAL PROPERTIES OF OBLIQUE 3D ISOLATION BEARINGS

An oblique three-dimensional (3D) isolation bearing was introduced based on the properties of lead rubber bearings (LRB) to meet the vertical strength and damping demands. A mechanical model considering the influence of the pressure and nonlinear stiffness degradation of LRB was established. The horizontal and vertical performance test was carried out on the 3D isolation bearings with inclination angles of 12 degrees and 15 degrees. The hysteretic behavior had non-parallel characteristics during the loading and unloading process. The vertical stiffness showed a nonlinear variation with the deformation. The variation of the vertical performance with the inclination angle and the vertical displacement was obtained. The proposed nonlinear theory and experimental results matched well. A numerical simulation of the 3D isolation bearings with different inclination angles was accomplished using the finite element method. The variations of the vertical nonlinear stiffness with the friction coefficient, shear strain, and inclination angle were discussed based on the simulation results.