基于车桥耦合振动的等截面连续梁桥多损伤识别研究

文章选用1/4车辆模型，用单元刚度的减少模拟裂缝损伤，对等截面连续梁桥进行损伤识别研究。利用MATLAB中的Cftool模块拟合离散的振型数据得到振型函数，再利用MATLAB模拟车辆匀速驶过桥梁的过程，求解车桥耦合振动方程，可得车辆与桥梁特殊位置的响应。研究结果表明：通过车体竖向速度响应比无损时增大的位置可以识别桥梁的损伤跨；根据车辆行驶到损伤跨时对应的该跨跨中竖向位移响应与无损时存在偏差的位置，可以识别桥梁存在损伤的范围；通过偏差的大小可以判断损伤的大小。

By selecting a quarter vehicle model, bridge crack damage was simulated with the reduction of unit stiffness, aiming at the identification of multiple damages of continuous beam bridge with constant cross-equal section. The vibration mode function was obtained by fitting the discrete vibration mode data of the bridge through the Cftool module in the MATLAB software. Then the MATLAB software was used to simulate the process of the vehicle traveling through the bridge at a constant speed, and the equation of the vehicle-bridge coupling vibration was solved. Finally, the vibration response of vehicle and bridge at special positions was calculated. The results show that the damaged span of the bridge can be identified according to the position where the vertical speed response of the vehicle body increases compared with non-damage conditions; the range of damage can be identified according to the position where the vertical displacement response in the middle of the damaged span deviates from that without damage when the vehicle travels to the damaged span; the size of the damage can be identified according to the size of the deviation.