车桥系统非平稳随机振动的PEM-PIM算法

Combined PEM-PIM scheme for the non-stationary random vibration analysis of vehicle-bridge systems

研究了车桥耦合系统受到路面不平激励而发生的非平稳随机振动。采用虚拟激励方法(PEM)将路面的竖向随机不平度精确地转化为一系列竖向简谐不平度的叠加,从而简化了运动方程的求解,在此基础上用精细积分法(PIM)的三种格式进行数值计算。这种基于虚拟激励法的精细积分(PEM-PIM)算法比通常的数值积分方法更真实地模拟了车辆作用力在时间域和空间域上的连续变化,也更精确地实施了数值积分。与广泛采用的Newmark方法比较,三种PEM-PIM格式处理这类问题时在分析精度和计算效率上都有显著的改善,而又各有特色。

Non-stationary random vibration of vehicle-bridge coupling systems subjected to the action of irregular road surface is investigated in this paper. Pseudo-excitation method （PEM） is applied firstly to transform the random surface roughness into the superposition of a series of deterministic pseudo harmonic surface unevenness and thus simplifies the solution of the dynamic equations considerably. Three alternative formats of precise integration method （PIM） are presented to compute the vertical vibration responses due to the pseudo harmonic unevenness. They can well simulate the continuous varying of the road forces exerting on the vehicle both in the time and space domains, and thus have remarkably overcome the shortcomings of the conventional numerical integration methods, such as the Newmark method. Numerical results show that, the proposed combined PEM-PIM scheme is much more accurate and efficient than the widely used Newmark method for the random responses analysis of vehicle-bridge coupling systems.