M KASHFI - PhD student, Department of Mechanical Engineering, Bu-Ali Sina University, Hamedan, Iran
G.H Majzoobi - Professor, Department of Mechanical Engineering, Bu-Ali Sina University, Hamedan, Iran
N Bonora - Professor, Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, Italy
G Iannitti - Ph.D. Researcher, Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, Italy

In the present work a new damage model based on CDM is proposed to predict the nonlinear behavior of woven glass fiber composite under tensile test. Orthotropic mechanical properties such as elasticity modulus and Poisson s ratio are determined by experiment. The tensile test showed that the material behavior was brittle elastic.However, the stress-strain curve was exhibited a nonlinear fashion. A new damage model was proposed and implemented via a user subroutine in MSC MARC. Moreover, the damage parameters were optimized by Genetic Algorithm. In conclusion the damage model can predict the nonlinear behavior of composite in both warp and weft direction with reasonable agreement in comparing with experiment.

Continuum damage mechanic, Woven fiber glass, Finite element, Iterative simulation, Orthotropic behavior