动载荷时域半解析识别方法

Semi-analytical method to identify dynamic load in time domain

基于模态空间转换、离散数据最小二乘拟合与模态叠加原理,提出一种动载荷时域半解析识别方法。通过模态空间转化将动载荷识别问题转化为模态坐标函数识别问题,以结构特性参数与已知自由度上的动响应为输入,利用最小二乘拟合得到模态坐标的拟合函数,根据叠加原理与结构动力学控制方程,识别出结构时域动载荷。分别用计算仿真与试验测试得到的时域加速度响应作为输入,实现时域动载荷的识别。识别结果与真实动载荷对比表明,本文的识别方法能较准确地识别结构动载荷值及载荷作用部位。

A semi-analytical method for dynamic load identification in time domain was proposed based on the approaches of modal space transformation, least square fitting and modal superposition. The problem of dynamic load identification was converted to the identification of modal coordinate functions by means of modal space transformation; using the structural characteristic parameters and dynamic responses at some given degrees of freedom as the inputs of load identification, the least square fitting was then employed to obtain the fitting functions of modal coordinates; finally, the dynamic loads in time domain were identified in the light of the principle of modal superposition and the governing equations of structural dynamics. In the identification process, acceleration responses derived from simulation and experiment were taken respectively as the inputs. The comparisons between the identified loads and the real ones show that, the method can meet the requirements of identifying the magnitudes of dynamic loads and their locations.