说明：  空间刚架刚度矩阵集成以及演示算例 其中： K_beam问件为空间刚架单元矩阵，是计算复杂空间刚架模型的基础。 TT文件为坐标转换矩阵。 prepare为算例。
(The integration of stiffness matrix of space rigid frame and the demonstration example. K_beam is the element matrix of space rigid frame, which is the basis of calculating the complex space rigid frame model. The TT file is the coordinate transformation matrix. Prepare is an example.)