Determination of material parameters for discrete damage mechanics analysis of carbon-epoxy laminates

Discrete damage mechanics (DDM) refers to micromechanics of damage constitutive models that, when incorporated into commercial finite element software via user material subroutines, are able to predict intralaminar transverse and shear damage initiation and evolution in terms of the fracture toughness of the composite. A methodology for determination of the fracture toughness is presented, based on fitting DDM model results to available experimental data. The applicability of the DDM model is studied by comparison to available experimental data for Carbon Epoxy laminates. Sensitivity of the DDM model to h- and p-refinement is studied. Also, prediction of modulus vs. applied strain is contrasted with ply discount results and the effect of in situ correction of strength is highlighted.