Constitutive modelling of the strain-rate dependency of fabric reinforced polymers

Among the various mechanisms which occur during impact, the strain rate effect plays a significant role on the mechanical response of layered carbon fibre reinforced polymer structure. In this work, the viscoelastic behaviour of the material is studied to introduce a strain-rate dependency. To preserve numerical efficiency the generalised Maxwell model, formulated in the strain-space, is taken as a basis. The non-linear viscoelastic behaviour is introduced by coupling the generalised Maxwell model with a pre-existing intralaminar matrix continuum damage model. The fact that the Maxwell model preserves the explicit scheme of the damage model leads to an efficient material model for impact simulations. This paper proposes a complete framework to implement the strain-rate sensitive damage model in an explicit finite element code (for low-speed impact simulations). For this purpose, the procedure of parameter identification, based on DynamicMechanical Analysis, is given. Furthermore, a challenging experimental procedure on high-speed jack device with a particular attention paid to the consistency of the results is proposed to validate the developed model.