自由运行结构动态载荷识别的格林函数法

将Green函数法应用于平动自由结构的载荷识别问题.不计刚-柔耦合效应,建立测点的绝对运动加速度和动态激励的卷积关系,Green核函数由整体刚体运动与弹性振动的脉冲响应迭加而成,采用正则化方法求解反卷积问题.对自由梁和组合薄壁结构给出两个算例,以数值仿真结果叠加20%噪声水平的随机噪声模拟实测响应,结果表明,Green函数法能有效地反演复杂平动自由结构的动载荷,正则化方法求解此类问题的稳健性和耐噪性强.文中得到的Green函数法对复杂自由结构体系的动载荷反演具有应用潜力.

Green kernel function approach of load identification for free structures with overall translation

Green function method was extended to deal with the load identification of free structures with overall translation. The kernel function was obtained by the superposition of impulse response of overall translation and elastic vibration without taking into account rigid flexible coupling effect, the convolution integral relationship of absolute motion acceleration at measuring point and dynamic loads was constructed, and the regularization algorithm of truncated singular value decomposition (TSVD) was applied to solve the corresponding de convolution equations. The proposed method was used to analyze a beam and a composite thin walled structure in the motion of overall translation. The numerical simulation data was superimposed with random noise of 20% noise level and taken as the input of inverse problem to identify the given dynamic load. It is shown that Green function approach described in the paper can be effectively used to identify the dynamic loads acting on complex structures of overall translation, and regularization algorithms can solve this type of inverse problems with high robustness and noise resistance.