二轴列车行经序列等跨桥时车辆共振响应分析

Resonance responses of vehicle during a two-axle train passing through sequential equal-span bridges

采用解析方法推导了二轴车通过序列等跨桥梁时车辆共振机理和条件,进而运用列车与桥梁动力分析模型及数值模拟方法来验证共振条件。结合重载铁路实例分析,以研究车辆共振对车桥系统影响规律。由研究结果得到以下几点结论:车辆出现共振现象是由车轮下规则的等跨梁重复性振频与车辆频率(车体点头或沉浮频率)一致而引起,就当前运营的重载列车而言,主共振车速常在正常运营速度之上,而次共振车速会落在列车运行速度范围之内;在车辆发生沉浮和点头主共振和次共振条件下,车辆动力响应和轮轨力将会被明显地放大;尽管车辆共振对桥梁动力响应的影响要比桥梁共振对车辆响应的影响要小,但对于短跨度桥梁而言,车辆共振也会显著加剧桥梁振动响应;当各节车辆均同时达到共振速度时,则会出现整列车出现全体性共振现象,是值得注意之处。

The vehicle resonance mechanism and conditions during a two-axle train passing through sequential equal-span bridges were derived analytically.Then,a simplified planar train-bridge dynamic analysis model and the numerical simulation method were employed to verify resonance conditions.A heavy haul railway system was taken as an example to study the effect laws of vehicle resonance on the vehicle-bridge system.The results showed that vehicle resonance phenomena are caused by the repetitive vibration frequency of sequential equal-span bridges being consistent with vehicle vibration frequency (train body nod or float frequency),for current heavy haul trains,the vehicle speed corresponding to the main resonance is often above the normal train operating speed,while that corresponding to the sub-resonance is within the train running speed range;when the vehicle has the float main resonance and the nod sub-resonance,its dynamic response and the wheel-rail force are amplified significantly;although the effect of vehicle resonance on bridge dynamic response is smaller than that of bridge resonance on vehicle dynamic response,for a short span railway bridge,the vehicle resonance can significantly intensify bridge dynamic response;when each vehicle of a train simultaneously reaches the resonant speed,the whole train resonance phenomenon occurs.