多维非平稳随机激励下隔震曲线梁桥的非线性振动控制

Nonlinear vibration control of an isolated curved girder bridge under multi-dimensional nonstationary random excitation

隔震曲线梁桥的平面不规则性引起的弯扭耦合效应,使其地震响应与隔震直梁桥相比更加复杂,为了有效的抑制隔震曲线梁桥地震中过大的梁体及支座位移,采取半主动控制策略来保证其安全性。采用经典的Bouc-Wen模型,建立考虑上部结构偏心的隔震曲线梁桥非线性振动控制方程,将该方程等效线性化后,输入考虑扭转分量的多维非平稳随机激励。利用混合精细积分法对无控、经典最优控制(COC)以及序列最优控制(SOC)后的隔震曲线梁桥进行随机响应分析。结果表明:在罕遇非平稳随机激励下,隔震曲线梁桥的动力响应呈现出非平稳特性,且考虑扭转分量的多维非平稳随机激励对隔震曲线梁桥动力响应影响要大于未考虑扭转分量下的;运用经典最优控制以及序列最优控制控制下的隔震曲线梁桥各个方向的的动力响应都有明显的减小,且结构动力响应的非平稳特性也得到了明显的抑制。

The coupling effect of bending and torsion caused by plane irregularity of an isolated curved girder bridge makes its seismic response more complex than that of the isolated straight girder bridge.In order to effectively restrain the excessive displacement of a beam and a bearing in the isolated curved girder bridge,a semi-active control strategy was adopted to ensure its safety.Based on the classical Bouc-Wen model,the nonlinear vibration control equation of the isolated curved girder bridge was established with considering the eccentricity of the upper structure,and after the equation was equivalently linearized,the multi-dimensional non-stationary random excitation considering the torsion component was input.The random response analysis of the isolated curved girder bridge after uncontrolled,classical optimal control(COC)and sequential optimal control(SOC)were carried out by using the hybrid precise integration method.Results show that the dynamic response of the isolated curved girder bridges presents non-stationary characteristics under rare non-stationary random excitations,and the influence of multi-dimensional non-stationary random excitation with considering the torsion component on the dynamic response of the isolated curved girder bridge is greater than that without the torsion component.The dynamic response of the isolated curved girder bridge in all directions are significantly reduced by using the classical optimal control and the sequential optimal control,and the non-stationary characteristics of the structural dynamic response are also obviously restrained.