A Three-Stage Explicit Stress-Strain Relations For Stainless Steel Alloys Applicable In Tension And Compression At Elevated Temperatures

摘要

Presented in this paper is an explicit full-range stress-strain relation for stainless steel alloys applicable at normal and elevated temperatures.The relation utilizes an approximation of the closed form inversion of a highly accurate three-stage stress-strain relation recently obtained from the Ramberg-Osgood equation.The three stage inversion is formulated using an appropriate rational function assumption to approximate the fractional deviation of the actual stress-strain relation from an idealized linear elastic behaviour.The temperature dependence on the stress-strain relation is then introduced by modifying the basic mechanical properties of stainless steel to account for the temperature effects.The proposed approximate inversion is applicable over the full-range of the stress well beyond the elastic region up to the ultimate stress.Moreover,the inversion can be applied to both tensile and compressive stresses.The proposed approximate inversion is tested over a wide range of material parameters as well as a wide range of temperatures.It is shown that the new expression results in stress-strain curves which are both qualitatively and quantitatively in excellent agreement with experimental results and the fully iterated numerical solution of the full-range stress-strain relation for normal as well as elevated temperatures.