响应残差校验的载荷识别方法

Load identification method based on residual error verification

机械结构受到的载荷难以直接测量,需要通过结构的频率响应函数以及实际工作状态下的响应求得.但是当结构所受载荷为内部激励时,导致频率响应函数无法通过测试获得.基于此,介绍了一种适用于工程实际的载荷识别方法,包括"实验模态修正有限元模型、最小二乘法求逆载荷识别、响应残差校验"3个步骤,设计了实验台架验证该方法的可行性.根据实验模态修正实验台架的有限元模型;选取不同测点,基于最小二乘理论识别载荷,分析了响应测点数目和位置对识别精度的影响;响应残差曲线与以力传感器测量得到的载荷误差曲线的变化规律一致,从而验证了响应残差是一种评价识别精度的有效手段.对台架进行实验和仿真计算验证了该方法的可行性,对工程实际具有一定的借鉴.

It＇s difficult to measure applied load acting on mechanical system directly,so frequency response functions and vibration responses in operation are needed to estimate load.However,it＇s impossible to measure frequency response functions when the type of load is internal？load.According to this situation,a strategy of load identification which is suitable for engineering is presented in this paper.It includes three steps,e.g.mode modification,least square identification and verified by the residual error of response.The feasibility of this method is demonstrated through the designed bench.According to the experimental modal analysis,finite element model of the bench is revised.Based on the least square method,the effects of the number of measuring points and position on the accuracy of identification are analyzed with the combination of different measuring points.The experimental results show that the residual error of response coincides well with force error.It demonstrates that the residual error of response is an effective method to evaluate the identification accuracy.The feasibility of the approach is verified through experiment and simulation,and this method provides a certain guide for practical engineering.