车辆气动力展向相关性传递函数及其对桥上运动车辆响应的影响

Transfer Function of Spanwise Correlation of Vehicle Aerodynamic Forces and Its Effects on the Responses of a Vehicle Running on a Bridge

为研究运动车辆气动力的展向相关性对桥上运动车辆响应的影响,在分析运动车辆顺风向和竖向脉动风速谱的基础上,发展出一种新型的运动车辆脉动风速相干函数形式,推导出与顺风向和竖向脉动风速对应的运动车辆气动力的展向相关性传递函数,并根据"余弦规则"得到作用在运动车辆上的抖振力谱。通过建立列车-轨道-桥梁多体系统耦合振动仿真模型,以单节列车在典型的高速铁路桥梁上行驶为例,对比不同车速、不同风速与不同地表类型时,运动车辆气动力的传递函数对桥上运动车辆响应的影响。研究结果表明:当考虑上述传递函数时,车辆响应的均方根均有不同程度的降低,其中对车体横向和竖向加速度均方根的影响最为显著;当车速为40m·s-1时,在考虑与不考虑传递函数情况下,车体横向加速度均方根的相对误差高达40.6%,车体竖向加速度均方根的相对误差也高达36.6%;随着车速的提高,各车辆响应均方根的相对误差均逐渐变小;随着风速的提高,轮重减载率和轮轨垂向力均方根的相对误差均逐渐变大,而车体竖向Sperling指标和轮轨横向力均方根的相对误差却先增加后减小;从A类地表类型到D类地表类型,车体加速度均方根以及车体Sperling指标的相对误差均逐渐增大,而轮轨力均方根、脱轨系数均方根、轮重减载率均方根的相对误差均先增大后减小。

To study the effects of the spanwise correlation of vehicle aerodynamic forces on the responses of a vehicle running on a bridge,a new form of the fluctuating wind coherence function relative to a running vehicle was developed based on its longitudinal and vertical fluctuating wind power spectra.The transfer functions of the spanwise correlation of the vehicle aerodynamic forces,corresponding to longitudinal and vertical fluctuating wind speeds,were proposed.In addition,the spectra of buffeting forces acting on the running vehicle were obtained in accordance with the cosine rule.By establishing the coupling vibration simulation model for a rail vehicletrack-bridge multibody system,a single rail car running on a typical high-speed railway bridge was considered as an example,and the effects of the above-mentioned transfer functions on the responses of a vehicle running on the bridge were investigated for different vehicle speeds,wind speeds,and terrain surface types.The results indicate that the root mean square(RMS)values of the vehicle responses decrease to different degrees when the above-mentioned transfer functions are considered,particularly for the lateral and vertical accelerations of the car body.When the vehicle speed is 40 m·s-1,the relative errors for the RMS of the lateral and vertical accelerations of the car body in the cases with and without consideration of the transfer functions are as high as 40.6% and 36.6%,respectively.However,the relative errors for the RMS of the vehicle responses gradually decrease in value as the vehicle speed increases.As the wind speed increases,the relative errors for the RMS of the wheel load reduction rate and wheel-rail vertical force gradually increase;however,the relative errors for the vertical Sperling index and the RMS of the wheel-rail lateral force first increase and then decrease.When the terrain surface type changes from A to D,the relative errors for the RMS of the accelerations and Sperling index of the car body gradually increase;however,the relative errors for the RMS of the wheel-rail force,derailment coefficient,and reduction rate of the wheel load first increase and then decrease.