基于实测数据的车轨耦合模型更新方法

提出了一种适用于车轨耦合系统的模型更新方法,其更新过程主要由两大步骤来实现:a.更新列车运行速度;b.更新扣件刚度。首先,建立了地铁列车车轨耦合系统模型,采用迭代的方法求解系统动力响应;其次,选取地铁普通整体道床轨道线路开展测试以获得现场实测数据,随后利用车轨耦合系统模型发现钢轨位移动力响应受扣件刚度影响较为明显,而受扣件阻尼影响较小。更新列车运行速度的主要目的是使激振主频更加吻合现场实测状况,在此基础上更新扣件刚度可使频域幅值更为接近。钢轨位移动力响应的频谱由列车周期荷载的一阶多次频率控制,这是由于轨道结构的多点连续支承特性所造成的。通过对比模型更新后的模拟结果与测试结果,验证了所提模型更新方法的可行性。研究结果表明,更新列车运行速度及扣件刚度是进行地铁列车与轨道耦合系统模型更新的有效方法之一。

Model Updating Method for Vehicle-Track System Based on Field Measurement

In this paper, a novel model updating method for the vehicle/track system in the subway is put forward. Present study indicates that the train speeds and fastening system stiffness are two key issues dominating the model updating process of the track subway system. For demonstration, a vehicle/track coupling model based on the multi-body system is presented and the dynamic response of track system subjected to the moving train is computed using an iterative method. Then, a typical subway track in service is selected for the present investigation to capture field testing data. The numerical predictions of the dynamic response of track computed by the proposed model updating method are verified and compared with the field testing results. The following conclusions are drawn: (1) the fastening system stiffness plays a more dominating role in affecting the dynamic response of the track than that of the fastening system damping; (2) updating the running speeds can influence the major excitation frequencies of running vehicle on the tracks, which may produce more consistent results referred to as field measurement; (3) updating fastening system stiffness may result in denser distribution of frequency amplitudes; and (4) the spectrum of rail displacements is dominated by n times of the first order train loadings since the effects of multiple supports on the track structures are taken into account.