桥梁抗风型TMD对车-桥耦合振动系统减振性能研究

Vibration reduction effect of bridge anti-wind type TMD on vehicle-bridge coupled vibration system

为研究桥梁抗风型调谐质量阻尼器(tuned mass damper, TMD)对车辆荷载引起结构振动的减振效果,并揭示车载作用下的TMD激振机理,提出了基于模态动能演化的多自由度结构TMD控制方法,确定了安装TMD的最优设计参数和布设位置;考虑桥梁有限元模型动力求解的通用性,基于桥梁三维动力分析系统BDANS软件建立了车-桥-TMD动力耦合分析系统;以经典单自由度移动弹簧质量过简支梁模型为研究对象,分析了车-桥-TMD系统振动特性,结合某深水区非通航桥梁抗风型TMD工程实例分析了TMD对车致振动的减振效果和机理。研究结果表明:TMD行程幅值与减振效果呈现正相关特点,即行程幅值越大对车-桥动力效应引起的振动减振效果越好;安装TMD可以显著提高结构的等效阻尼比,满足等效阻尼比>1%的工程需求,提高桥梁结构振动的稳定性;TMD在一定条件下可以减小车辆通过时引发桥梁竖向位移冲击效应,最大可减少3%左右;TMD对车-桥2个子系统的加速度瞬态峰值均起到了一定的抑制效果,尤其对桥梁结构竖向振动加速度作用效果明显,安装TMD后的桥梁跨中竖向振动加速度RMS值减少约20%;对大跨钢箱桥梁而言,相比较小的车辆荷载冲击效应,一阶竖弯呈邻跨反对称特性的桥梁结构在车辆通行过程中更容易激起TMD,使桥梁结构获得更佳的减振效果。

Here,to study vibration reduction effect of bridge anti-wind type tuned mass damper(TMD)on structural vibration caused by vehicle load,and to reveal exciting vibration mechanism of TMD under vehicle load,a multi-DOF structural TMD control method based on modal kinetic energy evolution was proposed,and the optimal design parameters and deployment positions for installing TMDs were determined.Considering the universality of dynamic solving for bridge finite element models,a vehicle-bridge-TMD dynamic coupled analysis system was established based on the bridge 3-D dynamic analysis system software BDANS.Taking a classic single-DOF moving mass-spring passing through a simply supported beam model as the study object,vibration characteristics of a vehicle-bridge-TMD system were analyzed.The vibration reduction effect and mechanism of TMD on vehicle-induced vibration were analyzed using an anti-wind TMD engineering example of a non-navigable bridge in a certain deep-water area.The study results showed that amplitude of TMD travel is positively correlated with the vibration reduction effect,i.e.,the larger the amplitude of TMD travel,the better the vibration reduction effect of TMD on vehicle-bridge coupled vibration system;installing TMD can significantly improve the equivalent damping ratio of bridge structure,meet the engineering requirement of equivalent damping ratio>1%,and improve the stability of bridge structure vibration;TMD can reduce the vertical displacement impact response of bridge caused by vehicle passing through under certain conditions with a maximum reduction of about 3%;TMD has a certain suppressing effect on transient peak accelerations of both vehicle and bridge subsystems,especially,on vertical vibration acceleration of bridge structure;after installing TMD,RMS value of vertical vibration acceleration at bridge mid-span decreases by about 20%;for large-span steel box-girder bridge,compared to smaller vehicle load impact responses,the bridge structure with first-order vertical bending modal shape exhibiting adjacent-span asymmetric feature can more easily trigger TMD during vehicle passing to obtain the better vibration reduction effect on bridge structure.