Genetic evolution of nonlinear material constitutive models

Abstract

Material constitutive model is highly nonlinear and multimodal in the large parameter space. A genetic evolution algorithm is thus proposed for its recognition. The nonlinear stress–strain relationship presented by several added multinomials, whose structure is not simplified, is automatically recognized from global response information, e.g., load vs. reflection data, obtained from a structure test through genetic evolution in global space. Nonlinear finite element analysis is used as a bridge to build a relationship between stress–strain data and load–deflection information. The potential of the proposed method is demonstrated by applying it to the macro-mechanical modeling of nonlinear behavior in advanced composite materials. A nonlinear material model for the ply is recognized using experimental results on a lamina plate [(±45)6]s to be a modification of Hahn–Tsai model [H.T. Hahn, S.W. Tsai, J. Compos. Mater. (1973) (7) 102]. The obtained nonlinear constitutive model is subsequently used to predict nonlinear behaviors of the [(±30)6]s and [(0/±45)4]s plates. The results are satisfying. This modeling procedure can be used as a method to guide to improve analysis of nonlinear behavior and damage of composite materials.