弹性支撑梁在移动荷载作用下的响应分析

RESPONSE OF BRIDGE WITH ELASTIC BEARING UNDER MOVING LOAD

考虑弹性支撑刚度对弹性支撑梁固有频率及模态的影响,比较前二阶频率受弹性支撑刚度影响的规律及大小.选取二阶模态,利用模态叠加原理,研究弹性支撑梁在移动荷载和移动车辆作用下的动力响应.研究中,一阶模态考虑为简支梁一阶模态与弹性支撑梁的刚体平动相叠加,二阶模态考虑为简支梁二阶模态与弹性支撑梁的刚体转动相叠加.研究结果表明:考虑二阶模态所得结果与仅取一阶模态所得结果相差较大,相差大小受弹性支撑刚度决定,特别是当移动车辆考虑为弹簧质量系统时,耦合振动响应受刚体转动模态影响明显,耦合作用力也存在较大的差异.

Considering the stiffness of elastic bearing,the frequencies and modal of the bridge with elastic bearing were studied.The first two frequencies were compared,and the regularity of frequencies change with stiffness of elastic bearing was obtained.Using modal superstition principal,the first two modal were used for analyzing the response of bridge with elastic bearing under moving load.The first modal of bridge with elastic bearing includes the rigid body translation and the first modal of simply supported beam.The second modal of bridge with elastic bearing includes the rigid body rotation and the first modal of simply supported beam.The solution obtained with two modals differs widely from that with only the first modal.Especially,when the vehicle is simulated as a spring-mass system,the coupling force has wider difference.