黏弹性阻尼器抗震疲劳性能试验加载制度研究

Research on loading protocol in seismic fatigue performance test of viscoelastic dampers

我国现行规范及规程对于黏弹性阻尼器抗震疲劳性能试验要求未能完全真实地反映其性能特点,使得许多性能优良的黏弹性阻尼器不能满足现行标准中的疲劳性能要求,而黏弹性阻尼器由于其黏弹性材料的特殊性,若其未发生破坏,放置一段时间后力学性能会有明显恢复。因此,针对黏弹性阻尼器抗震疲劳性能试验中的加载制度低估了黏弹性阻尼器性能这一问题,提出了一种改进的黏弹性阻尼器抗震疲劳性能试验加载制度,即先在100%应变幅值下预加载5圈以剔除初始刚度的影响,再按照"5圈100%应变幅值加载,20圈50%应变幅值加载,5圈100%应变幅值加载"的加载制度进行30圈加载。通过对比黏弹性阻尼器的滞回耗能,发现黏弹性阻尼器在改进加载制度下的滞回耗能大于绝大部分天然地震动下的滞回耗能,从能量的角度验证了所提改进加载制度的合理性。

Current codes and regulations in China for the seismic fatigue performance test of viscoelastic dampers are hard to fully reflect the actual performance characteristics of viscoelastic dampers,so many viscoelastic dampers with excellent performance still cannot meet codes requirements. However,due to the particularity of the viscoelastic material,the mechanical properties of viscoelastic dampers without damage will be restored after a period of time.Therefore,toward the underestimation of the performance in the seismic fatigue performance test of viscoelastic dampers,the improved loading protocol in the seismic fatigue performance test of viscoelastic dampers was proposed. It was suggested that viscoelastic dampers should be pre-loaded for five cycles at 100% strain amplitude to eliminate the influence of initial stiffness followed with another 30 cycles( five cycles at 100% strain amplitude,20 cycles at 50%strain amplitude,and then five cycles at 100% strain amplitude). By comparing the hysteretic energy of viscoelastic dampers,it is proved that the hysteretic energy of viscoelastic dampers under the proposed improved loading protocol is greater than that under most earthquake ground motions. Thus,the rationality of the proposed improved loading protocol is verified through the perspective of energy.