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中文核心期刊

柔性轮对的离散时间传递矩阵法建模及垂向振动

DISCRETE TIME TRANSFER MATRIX MODELING OF FlEXIBLE WHEELSET AND VERTICAL VIBRATION

  • 摘要: 针对铁道车辆轮对系统的弹性振动及台架高频激振试验仿真问题, 以离散时间传递矩阵法建立了柔性轮对振动模型. 基于Newmark-β隐式法积分格式推导了分布质量弹性轮轴、集总质量车轮及弹簧-阻尼单元的离散时间传递矩阵, 采用Riccati法、Newmark-β法实现轮对系统垂向振动加速度以及速度、位移的求解, 将轮对模型与采用新型显式积分法求解的构架、轨道轮组动力学模型集成, 完成机车车辆单轴滚振试验台的动力学建模, 提出了混合积分模式下动态仿真求解流程. 基于滚振试验台, 开展了轨道轮初始表面粗糙度、打磨多边形及局部凹陷状态下300 ~ 400 km/h高速运行试验, 同步开展了相应的动力学仿真, 通过在时域-频域对测试和计算结果的比较, 检验了理论模型. 结果表明, 在振动加速度的时域-频域特性和幅值分布上, 单轮对柔体模型总体能够较好反映500 Hz频率下系统的中高频振动规律, 有效捕捉车轮不圆、多边形磨耗、局部凹陷等动态激扰, 三种轨面状态下计算的轴箱加速度幅值误差总体低于9%, 模型具有较好的适应性和准确性. 但相关建模方法如何在复杂空间结构中应用需要进一步探索.

     

    Abstract: For the dynamic simulation problems of elastic vibration and high-frequency exciting test for railway wheelset, the discrete time transfer matrix method is applied to establish the flexible wheelset vibrating model. The discrete time transfer matrixes of distributed mass elastic axle, lumped mass wheel and spring-damping element in wheelset are derived based on the Newmark-β integration formula. Both the Riccati method and Newmark-β method are applied to solve the vertical vibrating accelerations, velocities and displacements of wheelset system. The wheelset dynamic model is then introduced into the bogie frame and rail roller submodels to form an integrated dynamic system, in which the latter submodels are solved by the new explicit integration method. The single-wheelset rolling and vibration dynamic model of railway vehicle is then completed. The solution flow of dynamic simulation in the mixed integral modes is presented subsequently. Based on the vibrating and rolling test rig, the high-speed running test within the speeds of 300 ~ 400 km/h is carried out in the conditions of surface initial roughness, grinded polygon and local depression for rail rollers. The corresponding dynamic simulation under the same running conditions is carried out simultaneously. Both the simulation and test results are compared in time-frequency domains to verify the theoretical model. Viewed from the perspective of time-frequency characteristics and amplitude distribution of vibration accelerations, the results indicate that, the flexible wheelset dynamics model can well reflect the medium-high frequency vibration rules for the system vibrations below the frequency of 500 Hz. The dynamic excitations such as wheel out of round, polygonal wear and local depression can be captured effectively. The amplitude errors of calculated axle-box accelerations under the above three roller surface conditions are lower than 9% in general. The model has good adaptability and precision. However, the application of relevant modeling methods in the complex spatial structures needs further exploration.

     

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