根据模态综合叠加技术的优势,提出基于精细积分算法(PIM)的车桥耦合振动模型新算法。考虑积分步长内荷载协调分解,通过插值函数将移动车辆荷载等效到单元节点,利用科茨积分格式求解Duhamel非齐次项荷栽。以移动常量力作用于简支梁桥为例,将解析解和多种迭代格式数值解进行对比,校验精细积分法结合科茨积分格式求解车桥耦合振动模型算法的准确性。以移动弹簧质量车模型作用于简支梁桥为例,分析积分步长、计算时间对Rung—Kutta法、Newmark-fl法及PIM法计算结果的影响。结果表明:基于模态综合叠加法并结合精细积分格式求解车桥耦合振动问题不受积分步长限制,具有快速收敛的优势。
According to the superiority of the modal superposition method, a new numerical algorithm based on precise integration method (PIM)was proposed to solve the problem of vehicle-bridge coupling vibration. The load decomposition coordination in an integration step was considered, and moving vehicle load was equivalent to element point through interpolating function, then Cotes integral format was introduced to solve Duhamel nonhomogeneous load. Taking a moving constant force on simply supported beam as an example, the veracity of Cotes integral format was verified through comparing the analytical solution with several numerical integral results. Taking a moving spring mass vehicle model on simply supported beam as an example, the effects of integral time step and computing time on computing results using Rung- Kutta method, Newmark-fi method and PIM were analyzed. The results show that the PIM lies in unlimited by integral step length, and has superiority of quick convergence in solving the problem of vehicle-bridge coupling vibration.