A multiscale progressive failure approach for composite laminates based on thermodynamical viscoelastic and damage models

This paper presents a multiscale progressive failure approach for composite materials which allows predicting the failure of a laminate from the thermo-mechanical properties (behaviour and strength) of the individual unidirectional plies. This kind of approach is predictive for different laminate layups and takes also into account the effects of ply failures on the macroscopic behaviour and the final laminate failure. For the first time to our knowledge, the viscosity of the matrix was introduced into the model for a more realistic description of the mesoscopic behaviour, especially for the non-linearity under shear loading. The mesoscopic failure criterion is based on physical principles and makes a distinction between the fibre failure and the interfibre failure modes. In order to describe the progressive failure of a laminate (ply after ply), a progressive degradation model, based on thermodynamical damage models, was developed. The definition of the final failure is also improved in order to predict the final failure more accurately, especially for [±θ]s laminates. Finally, some results (stress vs. strain laminate responses and macroscopic failure envelopes) are presented and compared with test data found in the literature.