ERROR ANALYSIS OF FINITE-ELEMENT RESULTS ON PLATES WITH NONUNIFORM GRIDS

DISCRETE Dirac delta functions in two dimensions and the governing plate differential equations are used to produce continuous approximations from discrete finite-element data on nonuniform grids. The continuous approximation can be differentiated to compute continuous stresses/moments at any point in the plate and, when substituted in the differential equations, provides a residual error. The paper presents application examples of the procedure and studies the use of the ''smoothed'' solution in a Zienkiewicz-Zhu error estimator to assess the performance of the present analysis. In an example involving the linear response of a clamped square plate under uniform transverse load, the present procedure dramatically corrected and smoothed the discrete finite element results.