Plastic Deformation of a Perforated Sheet With Nonuniform Circular Holes Along the Thickness Direction

Abstract

For a perforated sheet with circular holes, used in shadow masks, the diameter of the circular hole varies through the thickness, and the nonuniform circular holes are arranged in a triangular pattern. In order to simplify the analysis, a perforated sheet with equivalent circular holes of uniform diameter is proposed such that its plastic behavior is similar to that with the given nonuniform circular holes. In this study, a yield criterion is discussed for the perforated sheet with uniform circular holes by employing an equivalent continuum approach, which is then applied to examine the plastic deformation of the perforated sheet with nonuniform circular holes. The analytical results predicted by the theory, including those for the apparent yield stresses and strain ratios, are verified by the results obtained from the finite element analysis and also from experiments.