By the combined use of reduced integration and addition of nonconforming displacement modes, a highly effective new plate element has been established. The displacement field of this element was formed by adding nonconforming modes only to transverse displacement component of Ahmad-Irons' element and the element matrices are computed by the numerical integrations with modified orders.
Comparing with other elements, the superiority of the both NC8-4.1 and NC8-5.1 elements over the elements previously studied has been observed. The solutions with these elements converge to the true solutions very rapidly as the mesh is refined. These elements are also shown to be applicable to the wide range of thick and very thin plate problems.