Simulation of discrete damage evolution in laminated composite compact tension specimens

Damage progression in laminated Overheight Compact Tension specimens was modeled using discrete representations of individual cracks and delaminations. Matrix cracking and delamination initiation, propagation, and interaction, without any prior knowledge and/or meshing of matrix cracking surfaces, is accomplished by combining stress and fracture mechanics-based constitutive modeling within a mesh independent crack-modeling framework. Simulation results including only matrix damage for specimens with [45₂/90 ₂/-45₂/0₂]_s and [0 ₄/90₄]_2s stacking sequences were compared with load-displacement curves and 3D X-ray micro computed tomography results from tested specimens. Excellent correlation was shown between the simulated and experimental load-displacement curves including statistical variations and proper representation of both the curve non-linearity and peak load. Similarly, remarkable correlation between simulated and experimental damage extent was shown. Additionally, a [45/90/-45/0]_2s specimen exhibiting significant fiber fracture was modeled and results compared with experiment. Fiber fracture was simulated using a continuum damage mechanics approach in addition to the discrete cracking and delamination damage representations of matrix damage. The simulated load displacement curve and damage extent compared favorably with experimental results.