整体平动自由结构载荷时域识别技术研究

摘要

研究整体平动自由结构载荷识别的 Green 函数法及应用途径。建立测点绝对运动加速度与动态激励力卷积关系，采用截断奇异值分解的正则化方法求解反卷积问题。以受轴向激励自由梁为对象，考虑不变及变截面模量两种情形，讨论整体平动及变形运动在核函数中的构成比例与核函数矩阵病态特性关系，分析结构整体刚度及测点部位局部刚度对载荷反演精度的影响机制及测点布置需考虑的刚度因素，提高正则化方法计算稳健性；分析复杂的组合薄壁结构，以一点响应反求其在牵制释放实验中所受冲击载荷进行结构瞬态响应有限元仿真，比较多点仿真与实测结果，验证反求方法的有效性。%The green kernel function method to identify dynamic loads on structures with overall translation was studied.The convolution integral relationship between dynamic loads and absolute acceleration at measuring points was derived,and the regularization algorithm of truncated singular value decomposition was applied to solve corresponding de-convolution equations.The free beams with constant and variable stiffness distribution were analyzed.The effects of overall stiffness and local stiffness in the area of measuring point on the minimum singular values were examined.It is concluded that the large stiffness near measuring points can improve the computing robustness and noise resistance of the regularization method.The method proposed was used to identify the shock load on a composed thin-walled structure in hold down and release experiment.The response in numerical simulation based on load identification was compared with the measured result,and the validity and accuracy of the identification technique were verified.