本文根据广义协调原理，利用Ｆｅｒｇｕｓｏｎ曲面构造含有剪切变形影响的法向位移，与面内位移结合，得出适用于中厚度壳体的平直单元模型．算例说明本单元性能良好． In this paper, based on the principle of generalized coordination, the Ferguson surface is used to construct the normal displacement which contains the influence of shear deformation and combined with the in-plane displacement to obtain the flat element model suitable for medium thickness shell. An example shows that the unit has good performance.