基于改进分数阶Tikhonov正则化的桥梁移动载荷识别

Bridge moving load identification based on improved fractional Tikhonov regularization

针对整数阶Tikhonov正则化方法识别桥梁移动载荷识别精度较差的问题,提出一种基于改进分数阶Tikhonov正则化的桥梁移动载荷识别方法。根据时域法理论建立桥梁移动载荷识别模型,模拟双轴车辆在桥梁上行驶过程,通过核函数方法将移动载荷表示为弯矩响应和加速度响应核函数的微分形式,采用离散化方法将微分方程转化为线性方程组,通过改进分数阶Tikhonov正则化方法进行求解。结果表明:较分数阶Tikhonov正则化方法和整数阶Tikhonov正则化方法,采用改进分数阶Tikhonov正则化方法的移动载荷识别结果在识别精度和抗噪性上都有一定优势,且改进分数阶Tikhonov正则化方法在低噪声水平下载荷识别精度较高,识别误差仅为分数阶Tikhonov正则化方法的15%;识别结果受弯矩响应影响较小,且具有良好的鲁棒性,更适用于桥梁移动载荷的现场识别。

Aiming at the problem of poor identification accuracy of bridge moving load by integer Tikhonov regularization method(Tik),a bridge moving load identification method based on improved fractional Tikhonov regularization method(IF-Tik)is proposed.According to the theory of time domain method,the bridge moving load identification model is established to simulate the driving process of two axle vehicles on the bridge.The moving load is expressed as the differential form of moment response and acceleration response kernel function by kernel function method.The differential equation is transformed into linear equations by discretization method,which is solved by improved fractional Tikhonov regularization method.The results show that compared with F-Tik and Tik methods,IF-Tik method has certain advantages in recognition accuracy and noise resistance,and IF-Tik method has higher recognition accuracy at low noise level,and the recognition error is only 15%of F-Tik method;The identification result is less affected by the moment response,and has good robustness,which is more suitable for the field identification of bridge moving load.