Identification and validation of a hyperelastic model for self-reinforced polypropylene draping

Self-reinforced polypropylene (SRPP) is a composite in which the reinforcement and the matrix consist of the same polymer, namely polypropylene. The present work focuses on the development and experimental validation of an FE model for thermoforming of SRPP. The constitutive model of SRPP sheet is based on the Boisse – Charmetant hyperelastic law. Material properties required to fit the model were obtained from the tensile and picture frame shear tests performed at forming temperatures and bending test of a non-consolidated fabric at room temperature. The model is validated in comparison with the experimental draping data, with special attention to parameters and patterns of wrinkles. Samples, pre-heated to a surface temperature of 170–175 °C, were deformed up to 1–4 cm heights using a hemispherical mould with a 4.5 cm diameter. Overall, good qualitative correlation between experimental and modelling results is observed, which justifies use of the proposed model with the experimentally identified parameters for prediction of SRPP draping and subsequent analysis of the mechanical response of the consolidated part to loading.