A nonconforming scheme with high accuracy for the plate bending problem

The convergence order O(h2)O(h2) of the plate bending problem has been derived by the superconvergence methods or constructing new finite elements where shape function space consist of P3P3 space so far. In this paper, we can also present the same result of the Adini rectangular element by the interior penalty method. We built a new nonconforming scheme, where the penalty parameter is accurately estimated and the consistency term vanishes. Then, the error estimate can only be determined by the interpolation error.