Mathematical interpretation of nonlinear relationship of stainless steel stress and strain

Abstract

Basic distinctive characteristics of stainless steels are reflected in the nonlinear relationship of stress and strain, prominent ductility, strain hardening due to cold forming, asymmetry and anisotropy of material. These properties lead to a different behavior of structural elements of this material than the equivalent elements made of carbon steel. Implementation of a design concept based on an ideal elasto-plastic model of material such as carbon steel, often produces conservative results in case of stainless steel, which is already at a disadvantage due to its cost in construction engineering. Proper defining of recommendations for design and their implementation in technical codes requires a precise and accurate mathematical interpretation of nonlinearity of stainless steel. This paper presents the most important analytical models for description of the relationship of stress and strain of various alloys of stainless steel which have lately been developed worldwide. Most of these models are based on the original Ramberg-Osgood analytical expression.