Comparative analysis of optimisation methods for linking material parameters of exponential and power models: An application to cyclic stress–strain curves of ferritic stainless steel

Abstract

The four most commonly used optimisation methods for linking the material parameters of an exponential Armstrong–Frederick and a power Ramberg–Osgood model are compared for given cyclic stress–strain curves of a ferritic stainless steel EN 1.4512. These methods are the damped Gauss–Newton method, the Levenberg–Marquardt method, the Downhill Simplex method and a genetic algorithm. Globally optimal material parameters are obtained by parallel searches within the methods. The methods are tested for cyclic curves at 20 ℃, 300 ℃, 650 ℃ and 850 ℃. The optimal values of material parameters and R2 values are comparable, whereas the search paths, the numbers of steps to reach optimal solutions and the processing time of the methods differ.