With the increasing of raft foundation thickness , the hypothesis of kirchhoff will be invalid due to the incapable neglecting of transverse shearing deformation . the correct solution can not be deduced through theory of thin plate any more since the influence of transverse shearing deformation does not take into account 随着板厚度的增加，横向剪切变形不可忽略， kirchhoff假设不再成立，薄板理论已不能给出正确的解答，横向剪切变形的影响必须加以考虑。
In this article , it is systematically introduced the kirchhoff ' s thin plate theory and the reissner ' s moderately - thick plate theory in which the transverse shear force has been taken into account further the different hypotheses of the two theories are analyzed then the difference of the two theories is found out 本文系统地介绍了kirchhoff薄板和考虑横向剪切力作用的reissner中厚板的相关理论，分析了薄板、中厚板理论的两种不同假设，找到了二种理论主要区别。
The rayleigh - ritz method is used to lead to analytical expressions for the stiffness and mass matrices and load vector as well as their sensitivities , which uses the simple polynomials to define assumed displacement functions , geometry and construction of wing structures . excluding some selected terms from the displacement functions or using stiff springs at the specified locations imposes boundary conditions . the accuracy of calculated results is improved by including transverse shear effects and using multiple sets of ritz functions in the analysis 它使用简单多项式作为ritz基函数、定义翼面的几何和结构参数，利用rayleigh - ritz方法导出翼面结构的刚度矩阵、质量矩阵和载荷向量及其灵敏度的解析表达式，通过排除位移函数中某些选定的项或在指定点使用约束弹簧施加各种边界条件，考虑横向剪切变形和使用多组ritz基函数改进分析的质量，使用等效蒙皮和等效夹芯技术提高计算效率。
