风屏障的突风效应对桥上列车走行性的影响

为研究列车进出风屏障段时所受突风效应的影响，以一高速铁路多跨简支梁桥为研究对象，通过风洞试验测试了风屏障在100.0%、43.5%和0透风率情况下车-桥系统的气动特性；基于哑元耦合法，建立了风-车-桥系统分析模型，开展了两种风屏障布置形式（通长和非通长）时风屏障透风率和列车车速对列车动力响应的影响分析. 研究结果表明:设置风屏障时桥上列车的气动特性存在较大差异，尤其列车气动阻力系数在风屏障透风率0比透风率100.0%时减少87%；当风屏障通长布置时，风屏障防风效果显著，随着透风率的减小，列车动力响应大幅减小，其中轮重减载率减小达53%；当风屏障非通长布置情况时，列车在进入和离开风屏障区段时，突风效应对列车的横向加速度和竖向加速度均影响显著，透风率越低，加速度响应变化越剧烈，但对于轮轴横向力和轮重减载率的影响有限；随着车速的提高，突风效应造成的加速度响应总体上增大，呈明显的非线性变化. 

Impact of Sudden Change of Wind Loads on Running Performance of Vehicle on Bridge with Wind Barriers

To investigate the impact of sudden change of wind loads on a vehicle passing through the transition section with wind barriers, a multi-span simply-supported beam bridge of high-speed railway was taken as the research object. Aerodynamic characteristics of the vehicle-bridge system were studied by wind tunnel tests under three wind barrier porosities of 100.0%, 43.5% and 0. Based on the dummy body coupling (DBC) method, a wind-vehicle-bridge coupling simulation model was established. Effects of wind barrier porosities and vehicle operation speeds on the vehicle dynamic responses were analyzed with two types of wind barriers setting (continuously and non-continuously). The results show that aerodynamic characteristics of the vehicle change obviously due to the setting of wind barriers. Compared to the 100.0% wind barrier porosity condition, the drag coefficient of vehicle decreases 87% under the condition of 0 wind barrier porosity. The wind barriers set continuously have obvious wind shielding effects. With the decrease of the wind barrier porosities, the vehicle dynamic responses decrease greatly, and the wheel load reduction rate reaches 53%. With the wind barriers set non-continuously, the sudden change of wind loads has great effects on the lateral and vertical accelerations of the vehicle when it enters and leaves the wind barrier section. The lower the porosity of wind barriers is, the more violent the change of the acceleration response is, but the impact on the lateral force of the wheel axle and the wheel load reduction rate is limited. With the vehicle speed increasing, the responses of acceleration generally increase due to the sudden change of wind loads, in an obviously non-linear trend.