重载货车转向架非线性干摩擦力等效线性化及在车桥耦合中的应用

摘要

Equivalent linearization of nonlinear dry friction force was carried out for the bogie in heavy haul freight car using describing function approach based on the equality of average power in a period of vibration.Namely,the vertical and lateral nonlinear friction forces between wedge and bolster were equivalent to the vertical and lateral linear damping forces.The rotating frictional resistance moments of side bearing and center plate were linearly equivalent to rotating frictional damping forces,and then the equivalent linear dynamics model of heavy haul freight car was established.Taking C80 type heavy haul freight car for example,the dynamics simulation calculations of heavy haul freight car were executed by the given equivalent linear dynamics model and nonlinear dynamics model respectively.The results indicate that,although the equivalent linear dynamics model slightly increases the stability indexes of carbody in both vertical and lateral directions,wheel-rail lateral force,derailment coefficient and wheel load reduction rate,these parameters still are in the range of GB/T 5599-1985 standard,and satisfy the requirements of their own evaluation indexes.As a result,the correctness and rationality of describing function approach applied to the equivalent linearization of nonlinear dry friction force are verified.It illustrates that the equivalent linear dynamics model of heavy haul freight car based on describing function approach can substitute for the complicated nonlinear dynamics model to analyze the dynamic response of vehicle-bridge coupling when heavy haul freight car passes through the existing bridge.It provides a new effective way for the parameter optimization of nonlinear suspension system of heavy haul freight car as well as the dynamics performance analysis of vehicle-bridge coupling.%采用基于振动周期内平均功率相等的描述函数法,对重载货车转向架的非线性干摩擦力进行等效线性化,即将斜楔与摇枕间的垂向和横向非线性摩擦力线性等效为垂向和横向线性阻尼力,将旁承和心盘处的回转摩擦阻力矩线性等效为同转摩擦阻尼力,进而建立重载货车的等效线性动力学模型.以C80型重载货车为例,分别采用给出的等效线性动力学模型和非线性动力学模型进行重载货车动力学仿真计算.结果表明:等效线性动力学模型虽然小幅度增大了车体的垂向和横向平稳性指标、轮轨横向作用力、脱轨系数和轮重减载率,但是仍在GB/T 5599-1985标准范围内,满足其各项评价指标要求,验证了用描述函数法对非线性干摩擦力等效线性化的正确性和合理性；说明基于描述函数法的重载货车等效线性动力学模型可以替代复杂的非线性动力学模型进行重载货车通过既有桥梁的车桥耦合动力响应分析,为重载货车的非线性悬挂系统参数优化和车桥耦合动力学性能分析提供了新的有效途径.