Material constitutive model is highly nonlinear and multimodal in the large
parameter space. A genetic evolution algorithm is thus proposed for its re
cognition. The nonlinear stress-strain relationship presented by several ad
ded multinomials, whose structure is not simplified, is automatically recog
nized from global response information, e.g., load vs. reflection data, obt
ained from a structure test through genetic evolution in global space. Nonl
inear finite element analysis is used as a bridge to build a relationship b
etween stress-strain data and load-deflection information. The potential of
the proposed method is demonstrated by applying it to the macromechanical
modeling of nonlinear behavior in advanced composite materials. A nonlinear
material model for the ply is recognized using experimental results on a l
amina 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 t
he [(+/- 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 analysi
s of nonlinear behavior and damage of composite materials. (C) 2001 Elsevie
r Science B.V. All rights reserved.