Strength and Failure Characteristics of Thin Circular Membranes

Abstract

The problem treated in this paper concerns the deformation and failure characteristics of thin circular metal membranes. The problem originated in a research project on the elevated-temperature bulging of aluminum alloys, conducted at Case Institute of Technology under contract with the Office of Production Research and Development of the War Production Board. Commercially the problem relates to the design of safety diaphragms used for the protection of pressure vessels. Also, similar conditions of loading and geometry are present in certain structures subjected to underwater explosion or high hydrostatic pressure. The circular bulging of metal membranes also offers the possibility of investigating the fundamental properties of metal in biaxial stress and strain states. In this paper the instability phenomena encountered in the deformation of such shapes is analyzed in terms of strain distribution and also by previously developed equations relating the stress-strain and radius-strain functions. The paper also develops the fact that the circular bulge test appears particularly suitable for determining basic stress-strain relations to much higher strain values than are obtainable by conventional methods.