Statistical analysis of different mathematical models for stress-strain curves of AISI 321 stainless steel

This paper presents statistical analysis of data obtained by uniaxial tensile testing of AISI 321 stainless steel. This data is required as material input in numerical software, such as Abaqus, Ansys, MSC Marc, Nastran, etc. This data can be provided in the software as a set of points (piecewise linear model) that is cumbersome to enter, or it can be provided as a mathematical model, in the case of which the Finite Element Method (FEM) software calculates desired points directly from the mathematical model. Various mathematical models can be used to approximate tensile test data depending on the material loading state (linear, elasto-plastic, plastic). In this paper, the same uniaxial test data is analyzed, and curve fitting parameters are shown for each mathematical model.