斜风作用下风-车-桥非线性分析系统建立

为了从风作用方向的三维模拟和系统非线性2个角度实现风-车-桥系统的全三维高真实度模拟，首先建立斜风荷载处理方法，采用平均风分解理论对桥梁斜风进行分解，形成桥梁斜风荷载，把桥梁风作用方向模拟域由垂直于桥梁纵轴线的二维平面扩展到三维空间；采用矢量合成法则和线性插值方法，依据车辆位置函数确定桥上车辆任意位置和时刻的合成风速，并基于风洞试验获取车辆气动力系数，形成车辆斜风荷载。然后基于已建立的非线性分析系统，融合斜风荷载处理方法，构建斜风作用下的风-车-桥全三维非线性分析系统，并实现动态可视化。最后采用建立的分析系统，对系列风偏角工况下的桥梁空间动力响应和车辆安全进行分析和评价。结果表明：斜风作用下，桥上车辆事故指标值及桥梁位移响应随着风偏角增大总体上均呈现先减小后增大趋势，且极值均出现在非90°的锐角区；基于风向垂直于桥跨方向的假定所进行的桥梁设计和车辆安全性评价结果偏于不安全。

A Nonlinear Analysis System for Wind-vehicle-bridge Under Skew Wind

To achieve full three-dimensional high-fidelity simulation of the wind-vehicle-bridge system from the three-dimensional simulation of wind action and system nonlinearity, a processing method for skew wind load was first established. The mean wind decomposition theory was used to decompose the skew wind and form the skew wind load of the bridge, and the simulation domain of the wind direction was extended from the two-dimensional plane perpendicular to the longitudinal axis of the bridge to the three-dimensional space. According to the vehicle location function, the synthetic wind speed of the vehicle at any position and time on the bridge was determined using the vector synthesis method and linear interpolation method. Based on the aerodynamic coefficients of the vehicle obtained from a wind tunnel test, the skew wind loads were determined. Second, based on the established nonlinear analysis system and the processing method for the skew wind load, a three-dimensional nonlinear analysis system of the wind-vehicle-bridge was constructed, and dynamic visualization was realized. Finally, the dynamic response of the bridge and the safety of the vehicle under a series of wind yaw angles were analyzed and evaluated using the established analysis system. The results show that, under the action of skew wind, the vehicle accident index value and the displacement response of the bridge are generally reduced and then increase with increase in wind yaw angle, and all the extreme values appear in the non-90° acute-angle region. Bridge design and vehicle safety evaluation are less secure when the wind direction is perpendicular to the bridge.