考虑压力影响的高阻尼橡胶隔震支座速度#br# 相关性本构模型及其地震响应研究

隔震支座是基础隔震结构中的重要装置，高阻尼橡胶隔震支座具有隔震效果好，环保无污染等优点，但其力学性能复杂，应力-应变曲线与多种因素相关。本文提出了一种考虑压力影响的高阻尼橡胶隔震支座速度相关性本构模型，研究其对隔震结构地震响应的影响。首先，通过多步松弛试验和不同速度下的循环剪切试验探明加载速度和压力对高阻尼橡胶力学特性的影响。其次，提出一个基于改进超弹性Zener模型的支座本构模型来同时考虑加载速度和竖向压力，并根据高阻尼橡胶的材料试验结果识别模型中的参数，再通过支座试验验证模型的准确性。最后，分析某隔震结构在高阻尼橡胶隔震支座的速度相关性和近断层脉冲型地震动综合作用下的地震响应特点。结果表明：高阻尼橡胶隔震支座的速度相关性在近断层脉冲型地震作用下表现得较明显，会对隔震结构的地震响应产生影响，应在隔震设计中予以关注。

A rate-dependent constitutive model of high damping rubber bearings considering #br# the influence of compressive load and its effect on the seismic response

Isolation bearings are important devices in the base-isolated structures, high damping rubber bearings (HDRBs) possess desirable isolation performance and environmentally friendly characteristic. However, the mechanical properties of HDRBs are complicated, and the stress-strain curve may be affected by the comprehensive force, loading rate, etc. In this study, a rate-dependent constitutive model of the HDRB considering the influence of compressive force was proposed and its effects on the seismic response of structures were studied. Firstly, the influences of loading rate and compressive force on the mechanical behavior of HDRB were investigated by conducting multi-step relaxation tests and cyclic shear tests at different compressive forces and loading rates. Then, a rate-dependent constitutive model of HDRB was developed based on the improved hyperelastic Zener model, which may consider the effects of loading rate and compressive force simultaneously. The model parameters were identified from the material test results, and bearing tests were carried out to verify the accuracy of the model. Finally, the seismic response of an isolated structure under the far-field and near-fault pulse-like ground motions was evaluated by different mechanical models of the HDRBs to investigate its overall seismic performance. It is found that the rate-dependent behavior of HDRBs appears to be more evident under the near-fault pulse-like ground motions, and it may influence the seismic response of isolated structures and shall be paid attention in the isolation deign.