Analytical solutions of inerter-added sliding isolation structures to ground motions
Analytical solutions of inerter-added sliding isolation structures to ground motions
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DOI：
10.1016/j.ijmecsci.2022.107568
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发表时间：
2022-07
影响因子：
7.3
通讯作者：
Songtao Xue;Li Zhang;Liyu Xie;Ruifu Zhang;Jianfei Kang
中科院分区：
文献类型：
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作者：
Songtao Xue;Li Zhang;Liyu Xie;Ruifu Zhang;Jianfei Kang
以往的研究证明，在滑动隔震结构中添加惯性器可以在不影响上部结构控制效果的情况下减少隔震位移。然而，由于滑动隔震器具有很强的非线性，通常采用近似方法或数值分析来研究添加惯性的滑动隔震结构，这阻碍了对该结构内在工作机制的理解。本研究推导了谐波地震动下添加惯性体的滑动隔震结构在滑动和粘着运动状态下的精确解析解，并研究了附加惯性体对此类结构运动状态和响应的影响。本文的主要创新点是在滑动系统中采用惰性技术来提高性能，并明确表达添加惰性物质的滑动隔离结构的动态响应和运动模式，以帮助理解附加惰性物质的作用。建立了在谐波地面激励下添加惯性的滑动隔震结构的粘着运动和滑动运动的微分方程。分析结构的动力特性，并得出结构响应的精确解析解。给出了附加惰性滑动隔震结构运动的三种基本模式（即粘粘、粘滑和滑移模式）发生条件的显式形式。基于导出的解析解，进行了广泛的参数分析，以研究添加惰性物质对滑动隔震结构的运动模式和响应的影响。通过添加惰性体，与不添加惰性体的滑动隔震结构相比，添加惰性体的滑动隔震结构的上部结构的固有频率降低，阻尼比降低，地震动激励也减少。此外，惰性物使滑移模式更容易发生，这对于发生滑动时的滑动隔离结构是优选的。一般来说，增加惯性器的惯量有利于减少隔离位移，但与减少某些频率范围和大振幅激励下的最大加速度相反。建议在确定滑动隔震结构中惯性体的惯性时，在隔震位移的减少和加速度之间进行权衡。
Previous studies have proven that adding an inerter to a sliding isolation structure can reduce the isolation displacement without compromising the control effect of the superstructure. However, due to the strong nonlinearity of the sliding isolator, approximate methods or numerical analyses are adopted to investigate inerter-added sliding isolation structures, which hinders the understanding of the inherent working mechanisms of such structures. This study derives exact analytical solutions during both sliding and stick motion states of inerter-added sliding isolation structures under harmonic ground motions and investigates the influence of an additional inerter on the motion states and responses of such structures. The main novelties of this paper are the employment of the inerter technique in a sliding system for performance improvement and explicit expressions of the dynamic responses and motion modes for inerter-added sliding isolation structures that assist in understanding the role of the additional inerter. Differential equations are established for both the stick and sliding motions of inerter-added sliding isolation structures subjected to harmonic ground excitations. The dynamic characteristics of the structure are analyzed, and accurate analytical solutions are derived for structural responses. The explicit forms for the occurrence conditions of three fundamental modes (i.e., the stick-stick, stick-slip and slip-slip modes) for the motion of the inerter-added sliding isolation structures are presented. Based on the derived analytical solutions, extensive parametric analyses are conducted to investigate the influences of the added inerter on the motion modes and responses of sliding isolation structures. By adding an inerter, a decreased natural frequency, a decreased damping ratio and a reduction in ground motion excitation are observed for the vibration of the superstructure in the inerter-added sliding isolation structure compared to that in the sliding isolation structure without an inerter. Furthermore, the inerter causes the slip-slip mode to occur more easily, which is preferred for sliding isolation structures when sliding occurs. An increasing inertance of the inerter is beneficial for reducing isolation displacement in general but contrary to reducing maximum acceleration in some frequency ranges and excitations with large amplitudes. The trade-off between the reduction of isolation displacement and acceleration is recommended for determining the inertance of the inerter in sliding isolation structures.