jixian zaihe_combine fenbutu_6.2 excel

代码说明：

  通过修改输入excel文件中的铺层信息及材料属性，计算层合板的等效模量及极限强度，并绘制应力沿厚度方向的分布图(The equivalent modulus and ultimate strength of the laminates are calculated by modifying the information and material properties of the laminates inputted into excel files, and the stress distribution along the thickness direction is plotted.)