Damage and failure in low energy impact of fiber-reinforced polymeric composite laminates

We analyze the damage initiation, damage progression, and failure during 3-dimensional (3-D) elastoplastic deformations of a fiber reinforced polymeric laminated composite impacted by a low speed rigid sphere, and compare computed results with experimental findings available in the literature. Damage is assumed to initiate when one of Hashin's failure criteria is satisfied, and its evolution is modeled by an empirical relation proposed by Matzenmiller, Lubliner and Taylor. The transient nonlinear problem is solved by the finite element method (FEM). Contributions of the work include considering damage in 3-D rather than plane stress deformations of a laminated structure and elasto-plastic deformations of the composite. This has been accomplished by developing a user defined subroutine and implementing it in the FE software ABAQUS. From strains supplied by ABAQUS the material subroutine uses a micromechanics approach based on the method of cells and values of material parameters of constituents to calculate average stresses in an FE, and checks for Hashin's failure criteria. If damage has initiated in the material, the subroutine evaluates the damage developed, computes resulting stresses, and provides them to ABAQUS. The damage evolved at a material point is not allowed to decrease during unloading. The delamination failure mode is simulated by using the cohesive zone model available in ABAQUS. The computed time histories of the axial load acting on the impactor are found to agree well with the experimental ones available in the literature, and various damage and failure modes agree qualitatively with those observed in tests. (C) 2011 Elsevier Ltd. All rights reserved.