Indian Journal of Science and Technology

Abstract

Background/Objectives: To study about different models used for nonlinear analysis of stainless steel and to find an optimized equation for the nonlinear strain hardening exponent for stainless steel material. Methods/Statistical Analysis: There are lots of models proposed for analyzing the nonlinear behavior of the stainless steel. The base of all the models are model suggested by1 . But there exist lots of uncertainties in Ramberg Osgood suggested equation for nonlinear strain hardening parameter, which is using proof stress at 0.01 and 0.2 strains. In 2014 2 also proposed an equation for computing the nonlinear strain hardening parameter, which is using proof stress at 0.05 and 0.2 strains. The percentage error is less when compared with the Ramberg-Osgood equation, but still it shows some errors. In this work a new equation for nonlinear strain hardening model is developed using nonlinear regression technique with an optimized algorithm based on the comparative study of the above two models. Findings: A new equation for computing the nonlinear strain hardening parameter for stainless steel was proposed. The presently proposed equation for nonlinear strain hardening parameter is calculated by using proof stress corresponding to 0.01, 0.05 and 0.2 strains, which is showing excellent matching with the computer optimized values of nonlinear strain hardening exponent. The percentage errors with respect to the computer optimized values are very less when compared other models percentage errors. The Ramberg-Osgood equation is giving total error of thirty-five percentages; 2 model gives nearly nine percentages for ferritic stainless steel. Proposed model is showing an error percentage of two only. Application/Improvements: Proper nonlinear analysis of stainless steel is required for the economical use of sections and for getting more realistic assessment of the structural response of the material.

Keywords: Material Nonlinear Analysis, Nonlinear Strain Hardening Exponent N, Nonlinear Regression Analysis, Ramberg Osgood Model, Stainless Steel