为了得到系统的总体刚度矩阵和质量矩阵，我发现自己写的矩阵总是会有些误差。为了提高精度，可以先用nastran建模，利用nastran的矩阵即可-In order to obtain the overall system stiffness matrix and mass matrix, I found myself writing the matrix will always be some errors. To improve accuracy, can be modeled using na