多线铁路车桥耦合振动仿真研究

Simulation Study on Multiline Vehicle-Bridge Coupled Vibration

为了评估高速铁路上多线铁路桥梁列车运行安全性与舒适性,以渝黔铁路白沙沱大桥为例,采用多体系统动力学软件SIMPACK建立了CRH3动车和拖车三维空间动力学模型,并通过SIMPACK的子结构技术将动车和拖车组装成列车动力学模型;采用有限元软件ANSYS建立了桥梁的动力分析模型,计算其自振特性.根据列车和桥梁子系统之间的变形协调条件和力平衡条件,在轮轨接触面的节点上进行位移和力的数据传递,基于SIMPACK与ANSYS相结合的联合仿真方法首次进行多线车桥耦合振动仿真,分析了桥梁动力学指标及列车安全性指标和舒适性指标,探索了多线车桥耦合振动的一般规律和对列车安全性与舒适性的影响程度.研究结果表明:(1)三线列车共同作用下,与单线单独行车时对应动车和拖车的车辆安全性指标(脱轨系数、轮重减载率及轮轨横向力)几乎完全一致;车辆舒适性指标(车体竖向加速度、车体横向加速度、竖向舒适度指标及横向舒适度指标)中除个别竖向加速度约10%外,其余指标都在1%以内,表明由于桥梁刚度较大,桥梁振动对列车动力学指标的影响很小,单线和多线对应动力学指标非常接近,可近似采用单线单独行车时车辆动力学指标推测多线同时行车的对应指标.(2)三线列车共同作用下桥梁主跨跨中竖向位移比单线叠加位移略大,相差1%以内,竖向位移影响系数在1.001~1.006之间;三线列车共同作用下桥梁主跨跨中横向位移与单线代数叠加位移相近,相差±10%以内,主跨跨中横向位移影响系数在1.000左右,可以近似采用单线叠加的竖向位移和横向位移推测三线列车共同作用下的竖向位移和横向位移.(3)三线列车共同作用下桥梁主跨跨中竖向加速度绝对值比单线代数叠加后的绝对值小,影响系数在0.636~0.771之间,可参照单线代数叠加的桥梁竖向加速度保守评定桥梁的竖向加速度;三线列车共同作用下的主跨跨中横向加速度绝对值比单线行车横向加速度绝对值中的最大值小,可参照单线横向加速度绝对值的最大值保守评定桥梁横向加速度.

In order to evaluate the safety and comfort of trains for high-speed multiline railway bridges, it is necessary to perform a simulation research on coupled vibrations for multiline railway vehicle- bridges. For this study, the three-dimensional space dynamic models of CRH3 motor car and trailer were set up using a multibody system dynamics software SIMPACK, and the train dynamics model was assembled via the established CRH3 motor and trailer model by the substructure technology of SIMPACK. The dynamic analytical model of bridge was established by using finite element software ANSYS, for calculating the natural characteristics. Then, according to the deformation compatibility condition and force balance condition between the train system and bridge system, the data transfer of the displacement and force on the wheel-rail contact surface was conducted. The simulation study of multiline vehicle-bridge coupled vibrations was carried out by co-simulation based on SIMPACK and ANSYS for the first time. Meanwhile, the dynamic indexes of the bridge, comfort indexes, and safety indexes of the train were analysed to explore the general rules and influences of coupled vibrations on multiline vehicle- bridges. The research results are as follows： （1） The corresponding vehicle safety indexes （ derailment coefficient, wheel unloading ratio, and wheel/rail lateral force） under the combined action of three line trains are almost the same as those only under single line action. As for the vehicle comfort indexes （ vertical body acceleration, lateral body acceleration, vertical comfort index, and lateral comfort index）, most of the corresponding indexes under single line and three line action are very close （within 1 % difference） , the only exception being individual vertical body acceleration with slightly larger difference （about 10% ） between them. Hence, these comparisons show that the influence of bridge vibrations on the dynamic indexes of trains is small owing to the great stiffness of bridge structures. Thereby the values of corresponding dynamic indicators between single line condition and multiline condition are very close, i. e. the dynamic indexes of vehicles under multiline conditions can be speculated by those under single line conditions. （2） The midspan vertical displacement under the combined action of three lines is slightly larger than the algebra superposition displacement of single line, but less than 1 % , and the influence coefficient of vertical displacement is between 1.001 -1.006. The midspan lateral displacement under the combined action of three lines is close to the single line superposition displacement with about 10% difference, and the influence coefficient of vertical displacement is about 1. 000. Therefore, the midspan vertical and lateral displacements under the multiline condition can be speculated by superposing all single lines. （3） The absolute value of midspan vertical acceleration under the action of three line trains is smaller than that of algebraic superposition for single lines with influence coefficients between 0.636 - 0.771; hence, it is feasible to conservatively evaluate the vertical acceleration of a bridge under multiline condition referring to the superposition of all single lines. The absolute value of midspan lateral acceleration under the action of three line trains is smaller than the maximum value among the absolute values of the lateral accelerations of each single line; thus, the lateral acceleration of a bridge under multiline condition can be evaluated referring to its single line lateral acceleration.