Prediction of viscoelastic effective creep compliances in cracked cross-ply composite laminates

Viscoelastic effective creep compliances were predicted for symmetric composite laminates with constant matrix crack density. Following previous analytical models, the governing equations were solved in the Laplace domain, and the resulting displacement field was inverse Laplace transformed to obtain the displacement field, damage variables, and strain response to a given stress in the time domain. For the displacement field, both a series solution and a non-series solution were obtained. The non-series solution was then used to calculate the strain response of a cross-ply laminate subjected to constant stress under constant matrix crack density via the numerical inverse Laplace transform. To validate the model, the creep strains predicted using the model were compared with a finite element analysis solution, experimental results, and a synergistic damage mechanics solution.