三次样条函数在桥梁移动荷载识别中的应用

APPLICATION OF CUBIC SPLINE FUNCTION TO MOVING LOAD JDENTITICATION ON A BRIDGE

基于欧拉梁模型,介绍了移动荷载识别的一般原理,提出采用三次样条曲线拟合来识别桥梁移动荷载的方法,用三次样条函数逼近桥梁挠度,对逼近函数微分求得桥梁挠曲速度和加速度,并根据模态叠加原理将挠度、速度、加速度转换为模态响应,由模态坐标方程和最小二乘法识别桥上移动荷载。通过计算机仿真,利用算例测试识别误差,获得的结果较理想。

General principle of identification of moving forces on a bridge based on a Euler beam model is introduced,cubic spline curve fitting is adopted to identify the moving force on the bridge.Using cubic spline function to approach the bridge beam deflection responses,its velocities and accelerations are calculated by using central difference method,and all three kinds of the responses are changed into the modal responses through modal superposition principle,then the moving forces are identified with the least square method based on the modal coordinate equation of the beam.The results of numerical simulation show that the method has high identification accuracy.