基于车桥耦合随机振动的桥梁动力安全性分析

Safety Analysis of the Bridge Dynamic Performance Based on Train-Bridge Coupling Random Vibration

研究目的：列车通过桥梁时，过大的桥梁振动会影响桥上列车运行的安全性。为保障列车的安全平稳运行，需建立考虑车桥耦合的随机振动模型，并对桥梁动力性能进行分析。本文基于空间车桥时变耦合系统模型，引入不平顺功率谱，编制基于MATLAB的车桥耦合随机振动分析程序，采用虚拟激励法计算车桥振动响应的标准差。研究结论：（1）与Monte Carlo法相比，虚拟激励法对标准差以及响应功率谱的求解十分简单快速，虚拟激励法分析车桥随机振动精度更高，计算效率提高了1～2个数量级；（2）利用三倍标准差原理，得到随机响应可能出现的上下界限区间，与规范限值比较，从而为桥梁动力安全性分析提供一种新思路；（3）桥梁跨中横向加速度和横向振幅的最大值和最小值曲线基本呈对称分布，其随机性较大，对于桥梁竖向加速度，确定性响应部分与由轨道不平顺引起的随机响应同样重要；（4）桥梁跨中竖向位移的随机性不大，主要由确定性荷载决定其大小；（5）该研究成果可为考虑车桥耦合随机振动的桥梁动力性能评价提供科学依据。

Research purposes： The excessive bridge vibration caused by train will affect tbe safety of train running when it is crossing the bridge. In order to ensure the safety and steady, a train - bridge coupling random vibration model need to be built and the bridge dynamic performance should be analyzed. Based on the space time varying train - bridge cotiplitig system model and track irregularity power spectrum, this paper designed a train - bridge coupled random vibration analysis program by using MATLAB, calculated the standard deviation value for the random response of the train- bridge system by adopting pseudo excitation method. Research conclusions： （ 1 ） Compared with the Monte Carlo method, the pseudo excitation method is a simple and rapid way in working out the standard deviation value and response power spectrum. It has higher accuracy and computation efficiency by 1 -2 order of magnitudes. （2） The range of the random vibration response was obtained by using the theory of triple standard deviation, and the paper compared it with the existing specification limits, provided a new thought for the bridge dynamic security analysis. （ 3 ） The maximum value and minimum value curves of the lateral acceleration and amplitude are symmetrical and most random. As to the vertical acceleration, the deterministic part of the response is as important as the standard deviation caused by the track irregularity. （4） The vertical displacement is of less randomness and mainly determined by the determined loads. （5） The result provides a scientific basis for bridge dynamic performance evaluation of train - bridge coupling random vibration.