Patent Document ID: 20150370936
Application ID: 14765208
Patent Flag: 0

Claim One:
1. A stress-strain relation simulation method comprising: an experimental-value acquisition step of plastically deforming an elastic-plastic material to acquire experimental values of a stress-strain relation; a first material-constant identification step of, by a computer, with a kinematic-hardening incremental vector dα ij of a yield surface in an elastic-plastic constitutive model as Equation (1), the elastic-plastic constitutive model being defined as a function of stress and back stress, identifying material constants contained in the elastic-plastic constitutive model with the experimental values acquired at the experimental-value acquisition step; a second material-constant identification step of, by the computer, based on the Equation (1) into which the material constants identified at the first material-constant identification step are substituted and based on the experimental values acquired at the experimental-value acquisition step, identifying material constants contained in Equation (2); and a step of, by the computer, simulating the stress-strain relation of the elastic-plastic material with the Equation (1) and the Equation (2) into which the material constants identified are substituted, and the elastic-plastic constitutive model. d α ij = [ C ( a Y ) ( σ ij - α ij ) - C 0 ρ X ij ] d ɛ eq p ( 1 ) C = C a + C c exp ( - X eq n A ) where a : maximum value of movement of yield surface Y : yield stress α ij : movement vector of yield surface σ ij : stress vector X ij : yield - surface kinematic - hardening amount after stress reversal ( X eq is equivalent value thereof ) d ɛ eq p : equivalent plastic - strain increment C 0 , C c , A , n : material constants ( 2 )