一种曲柄连杆式惯容器的力学性能与隔震性能研究

STUDY ON MECHANICAL PROPERTIES AND SEISMIC ISOLATION PERFORMANCES OF A CRANK TRAIN INERTER

基于惯容器(inerter)的耗能装置近年来受到结构减隔振(震)领域学者的极大关注。该文研究了一种新型惯容器——曲柄连杆式惯容器(CTI)。CTI由曲柄、连杆、齿轮箱和飞轮组成,具有表观质量可调和位移兼容性强等优点。提出了CTI装置与隔震支座在桥梁抗震中的联合布置形式。推导得到了CTI的表观质量解析表达式,及其线性近似条件。对CTI样机开展了不同表观质量及不同工作姿态下的力学性能试验。以一座典型的三跨变截面连续梁桥为例,采用数值方法研究了CTI在桥梁抗震中的参数设计方法并验证了其可靠性。研究结果表明:CTI可简化为线性惯容器的条件为最大变形应小于曲柄长度的0.312倍,连杆长度应大于曲柄长度的1.803倍。力学性能试验得到的表观质量与理论结果基本一致,通过改变曲柄长度可实现表观质量的精确调节,在线性工作范围内连杆工作姿态对表观质量影响不大。将CTI与隔震支座组合使用可在保证不发生落梁的情况下适度放大主墩顶处隔震支座的变形,提高其耗能效果,从而降低桥梁下部结构的地震响应。

In recent years,energy dissipation devices based on the inerter have received great attention in the field of structural vibration control and isolation.A novel Crank Train Inerter(CTI)is studied in this paper.It is composed of a crank,a linking rod,a gearbox and a flywheel,and has the advantages of convenient adjustment of the inertance and strong displacement compatibility.The CTI device and its arrangement with the isolation bearings in anti-seismic bridges are proposed.The analytical expression of inertance of the CTI and the linear approximation condition is derived.A prototype CTI with different inertances is manufactured for mechanical performance tests under different working postures.The vibration control performance of CTI is verified in the seismic design of a three-span continuous beam bridge with variable cross section by numerical simulations,and the parameter design method for CTI is proposed.The results show that the CTI can be approximated as a linear inerter on the condition that the maximum displacement of the structure is less than 0.312 times of the crank length,while the length of the linking rod is greater than 1.803 times of the crank length.The inertances obtained from the tests are consistent with the theoretical results.The inertance can be adjusted by changing the crank length,while it would not be affected by the posture of the linking rod in the linear working range.The seismic responses of the bridge substructure can be reduced by combining the isolation bearings with the CTIs,which enlarges the deformation and energy dissipation of the isolation bearing without unseating.