路面谱函数对车桥耦合随机振动敏感性分析

Sensitivity Analysis of Vehicle-Bridge Coupling Random Vibration Based on Road Roughness Spectral Function

将桥梁离散为梁单元,车辆简化为两自由度车模型,基于虚拟激励法建立车桥耦合随机振动模型。分别以GB7031谱、Wang谱及ISO谱三种路面不平顺谱函数作为不平顺激励输入,研究路面谱函数对简支梁桥及车辆振动响应的影响。分析三种路面功率谱对桥梁竖向振动响应的影响,研究不同路面谱函数作用下车速对桥梁振动响应的敏感性及车辆振动对路面谱函数的敏感性。研究结果表明:三种路面谱函数引起的简支梁桥跨中竖向位移均方根曲线形状相似;路面谱与车桥耦合共同作用,桥梁及车辆共振频率出现在桥梁一阶频率处;ISO谱引起的车辆振动响应受车速变化敏感性较弱,但桥梁振动响应受车速影响敏感性较强;GB7031谱和Wang谱引起车辆和桥梁的动力响应及频率特性接近,GB7031谱计算结果略大于Wang谱。

A new random vibration model of vehicle-bridge systems using pseudo excitation method(PEM)is proposed,based on the bridge modeled as beam elements and the vehicle modeled as two-degrees of freedom mass-spring-damper system.The responses of vehicle and bridge caused by road spectrum functions are researched based on the GB7031 spectrum,Wang spectrum and ISO spectrum,respectivley.The research covers the effect on vertical dynamic response of bridge,the sensitivity of bridge vibration due to vehicle speed and the dynamic responses of vehicle caused by road spectrum function.The results reveal the following conclusions:three road spectrums have the similarity vertical displacement root mean square(RMS)curve at mid-span;the resonance frequency appears at the bridge′s fundamental frequency;the vibration responses of vehicle caused by ISO spectrum change with vehicle speed weakly.However,thebridge dynamic responses caused by ISO spectrum show evident sensitivity in vehicle velocity.The dynamic response and resonance frequency of vehicle and bridge coupling caused by the GB7031 spectrum are approach to that of the Wang spectrum.The result of GB7031 spectrum is slightly greater than that of the Wang spectrum.