基于改进迭代模型的车-桥耦合系统竖向随机振动研究

采用改进的车-桥耦合系统迭代计算模型,建立了基于虚拟激励法(PEM)的列车-轨道-桥梁竖向随机振动分析模型.采用虚拟激励法将轨道不平顺精确地转化为一系列竖向简谐不平顺的叠加,并运用分离迭代法求解车-桥耦合系统振动方程.以CRH2高速列车通过5跨简支梁桥为例,对改进的车-桥耦合系统迭代计算模型的计算精度和效率进行了验证.结果表明:在保持与传统模型相同计算精度的前提下,改进模型能使计算效率提高5倍左右.通过对列车-轨道-简支梁桥竖向随机振动响应中确定性激励引起的均值和轨道不平顺引起的均方根进行分析可知:桥梁竖向位移主要受列车自重控制,轨道不平顺引起的桥梁竖向位移影响很小;桥梁和车体竖向加速度受轨道不平顺影响显著,改善线路条件能有效提高列车的乘车舒适性;同时,车速越高,桥梁和车辆随机响应的均方根越大,由轨道不平顺引起的耦合系统振动响应的离散度越大.

Study on Vertical Random Vibration of Train-bridge Coupled System Based on Improved Iteration Model

By using the improved iteration model for train-bridge coupled system, the analysis model of train-track bridge vertical random vibration based on Pseudo Excitation Method (PEM) was established. PEM was applied to transform the random track irregularities into the superposition of a series of vertical harmonic irregularities, while the iteration calculation was applied to solve the equation of the train-bridge coupled system. Taking a five-span simply-supported beam bridge passed through by a CRH2 high-speed train as numerical example, the accuracy and efficiency of the improved iteration model for train-bridge coupled system was verified. The results show that the calculation efficiency of the improved model is about 5 times that of the conventional model under the same calculation accuracy. The mean value and the root mean square (RMS) of the vertical random vibration response for train-track-simply supported beam bridge, which are caused by deterministic load and track irregularities, respectively, were calculated. It can be seen that the vertical displacement of the bridge is mainly controlled by the weight of the train, but the excitation of track irregularity has little effect on it. The vertical acceleration of the bridge and car bodies are significantly influenced by track irregularities, and the improvement of the track condition can effectively improve the riding comfort. The RMS of the train-bridge coupled system random vibration and the discrete of the vibration caused by track irregularities increase with the acceleration of train speed.