Constitutive modelling with a novel two-step optimization for an Al-Zn-Mg-Cu alloy and its application in FEA

Abstract The modified Johnson-Cook constitutive model was developed for describing the flow behavior of Al-7.8Zn-1.65Mg-2.0Cu (wt%) alloy based on curves in temperature range 300 °C?450 °C and strain rate 0.01 s ?1 ? 10 which were obtained by isothermal compression tests conducted a Gleeble-3500 simulator. A two-step optimization method proposed to optimize prediction precision according evaluation average absolute relative error (AARE). By using traversal procedure calculating under different reference conditions, this evaluator found varying 4.1837% 11.105%, revealing great influence condition precision, then (RCO) conducted. Genetic algorithm (GA) introduced as second step (TSO) material constants model, furtherly improved reducing AARE-value 3.801%. models before after written into subroutines software DEFORM investigated through finite element analysis (FEA). simulated results (forming load rise) revealed that TSO has highest agreement with experimental.