Forming limit diagram of perforated sheet

Abstract

The proper design and manufacture of tube sheets in heat exchangers and shadow masks in color picture tubes require the characterization of the deformation behavior of perforated sheets containing a large number of holes. The limit or failure strains in sheet metal forming are best represented by a forming limit curve (FLC) which indicates the onset of necking over all possible combinations of strains in the plane. A number of theoretical treatments have been developed to predict the FLC of continuum materials. However, there are few reports on the experimental and theoretical studies on FLC for a perforated sheet. The purpose of this paper is to propose a model which can explain the FLC of a perforated sheet for dot-type shadow mask.