An Improved Estimate for the Error in the Classical, Linear Theory of Plate Bending*

The relative mean square error in the three-dimensional stress field predicted by classical plate theory is shown to be OQi/L^)2, where h is the plate thickness and Lj. is a mean square measure of the wavelength of the midplane deformation pattern. This improves a recent result of Nordgren who obtained a relative error estimate of 0(h/L*). The improved error estimate, which, like Nordgren's, is based on the PragerSynge hypercircle theorem in elasticity, is obtained by constructing a kinematically admissible three-dimensional displacement field that depends on the solution of the classical plate equations but which yields an accurate, nonzero distribution of the transverse shearing strain through the thickness.