Compos.Struct 93(9), 2241-2249, 2011
A CONSTITUTIVE MODEL FOR FIBER-REINFORCED POLYMER PLIES
ACCOUNTING FOR PLASTICITY AND BRITTLE DAMAGE INCLUDING
SOFTENING - IMPLEMENTATION FOR IMPLICIT FEM
T. Flatscher, H.E. Pettermann
Institute of Lightweight Design and Structural
A constitutive ply model is developed to allow for the simulation of laminated
structures made of fiber-reinforced polymers.
The model accounts for stiffness degradation accompanied by strain hardening
(i.e. distributed brittle damage), unrecoverable strain accumulation (i.e.
multi-surface plasticity), and stiffness degradation accompanied by strain
softening (i.e. localized brittle damage).
Owing to the characteristics of such ply materials the model handles these
effects and their evolutions in an anisotropic manner.
The constitutive model is briefly reviewed with respect to distributed damage
and plasticity, and the extension to incorporate softening is given in detail.
The implementation as material routine for an implicit FEM package and the
computation of the material Jacobian matrix is presented.
Additional measures are adopted for improving/achieving convergence, as being
required for the treatment of material softening within numerical solution
The application of the constitutive model for structural analysis is
demonstrated by presenting simulation results from Open Hole Tension
The predictions include the overall non-linear response until structural
failure and the local distribution and evolution of the mechanisms incorporated
in the constitutive ply model.
Discussion of these results and comparison to literature show that crucial
intra-ply mechanisms are captured well by the proposed constitutive model.