基于 VMD 的简支梁动力响应计算冲击系数研究

Study on Calculating Impact Coefficient of Simple-supported Beam Dynamic Response Based on VMD

摘要:

分析现行荷载试验规范中对冲击系数计算方法存在的难点，为了从车辆过桥产生的动力响应中准确获取准静态响应，首先对桥梁振动方程进行了简化分析，然后利用桥梁动力响应曲线在频域上低频为准静态部分，高频为振荡曲线这一特性，提出一种变分模态分解VMD（Variational Mode Decomposition）结合HHT（Hilbert-Huang Transform）边际谱的方法。该方法通过仿真分析介绍了从动力响应中分解重构准静态响应成分的具体过程，最后将该方法应用于实际案例中。结果表明：该方法在车辆速度较低时能够准确快速提取结构的准静态响应，以提供桥梁结构安全运营和健康状态评估所需的参考依据。

Abstract:

The difficulties in the calculation method of impact coefficient in the current load test specification are analyzed. In order to accurately obtain the quasi-static response from the dynamic response of the vehicle passing through the bridge, the vibration equation of the bridge is simplified and analyzed. Then, a method of VMD (Variational Mode Decomposition) combined with HHT (Hilbert-Huang Transform) marginal spectrum is proposed according to the characteristic that the bridge dynamic response curve is quasi-static at low frequency and oscillatory at high frequency. The specific process of decomposing and reconstructing the quasi-static response components from the dynamic response is introduced through simulation analysis. Finally, the method is applied to practical cases. The results show that this method can accurately and quickly extract the quasi-static response at low vehicle speed, which can provide a reference for the safe operation and health state evaluation of bridge structures.