Viscoelastic viscoplastic model for aeronautical thermoplastic laminates at high temperature: Validation on high stress gradient structures

This study was aimed at validating a numerical model accounting for the influence of time-dependent effects of thermoplastic PolyPhenyleneSulfide (PPS) matrix on the behavior of carbon woven fiber reinforced PPS laminates at temperatures exceeding its Tg, when matrix viscoelasticity and viscoplasticity are prominent. This model combines a linear spectral viscoelastic model and a generalized Norton-type viscoplastic model, and was implemented into the Finite Element code Cast3m. From the macroscopic response standpoint, the validation of the model has been achieved by means of tests on high gradient structures at T > Tg (perforated with a central hole, single-edge notched, asymmetric double-edge notched specimens). Lastly, a full-field measurement technique (Digital Image Correlation) has been used at high temperature to test the model's ability to qualitatively and quantitatively predict the surface strains distribution of TP composites in high gradient structures.