基于车桥耦合振动的统计矩曲率梁式桥损伤识别研究

Research on Damage Identification of Beam Bridge with Statistical Moment Curvature Based on Vehicle Bridge Coupling Vibration

鉴于传统曲率指标桥梁损伤识别方法抗噪性能较弱和识别效率较低等问题,提出了一种基于统计矩曲率指标和车桥耦合振动理论的数据驱动桥梁损伤识别方法。首先,在牵引车的拖动下,利用2辆测试车静止时对相邻指定测点同步采集加速度响应信号,并计算相应信号的统计矩曲率,拖动2辆测试车重复该操作直至完成对整跨桥梁所有测点的采集及计算;然后对比前一状态下的桥梁各测点统计矩曲率值,将不同状态下的测点曲率值相减后绘制沿桥梁纵向变化的统计矩曲率差异曲线,基于曲线突出变化的测点即可获得桥梁损伤位置;进一步构建以统计矩曲率为参数的目标函数,实现桥梁模型修正,获取桥梁的损伤程度。首次推导了统计矩曲率与振型及其刚度之间的理论关系,并通过数值模拟研究了不同参数变化对该方法的影响,最后采用实桥测试验证了本文方法的实际可操作性。研究结果表明:与振型曲率和柔度曲率类指标相比,采用统计矩曲率指标识别损伤位置具有更好的抗噪性能和更高的识别效率;同时相对传统的传递率损伤识别方法,该方法对损伤的定位和损伤程度判断都具有更好的效果,且识别误差更小。

In view of the weak anti-noise performance and low identification efficiency of the traditional curvature index in bridge damage identification method,a data-driven bridge damage identification method based on statistical moment curvature index and vehicle bridge coupling vibration theory was proposed.Firstly,under the drag of the tractor,two test vehicles were used o synchronously collect acceleration response signals from adjacent designated measuring points when it was stationary;and the statistical moment curvature of the corresponding signals were calculated.The two test vehicles were dragged to repeat the operation until the collection and calculation of all measuring points of the whole span bridge were completed,and then the statistical moment curvature values of each measuring point of the bridge were compared in the previous state.After subtracting the curvature values of measuring points in different states,the statistical moment curvature difference curve varying along the longitudinal direction of the bridge can be drawn,and the damage position of the bridge can be obtained based on the measuring points with prominent changes in the curve.Further,the objective function with statistical moment curvature as the parameter was constructed to modify the bridge model and obtained the damage degree of the bridge.In this paper,the theoretical relationship between statistical moment curvature and vibration mode shape and its stiffness was derived for the first time,and the influence of different parameters on this method was studied through numerical simulation.Finally,the practical operability of this method was verified by practical bridge test.The results show that compared with vibration mode curvature and flexibility curvature index,the statistical moment curvature index has shown better anti-noise performance and higher recognition efficiency.At the same time,compared with the traditional transmission rate damage identification method,this method has behaved better effect on the location and degree of damage,and the identification error is smaller.