Experimental characterization and computational simulations of the low-velocity impact behaviour of polypropylene

Abstract

The objective of this work is to validate predictive models for the simulation of the mechanical response of polypropylene undergoing impact situations. The transferability of material parameters deduced from a particular loading scenario (uniaxial loading) to a different loading situation (multiaxial loading) was studied. The material was modelled with a modified viscoplastic phenomenological model based on the G'Sell–Jonas equation. To perform the numerical simulations, a user-material subroutine (VUMAT) was implemented in the ABAQUS/explicit finite element code. Constitutive parameters for the model were determined from isostrain rate uniaxial tensile impact test data using an inverse calibration technique. In addition, falling-weight low-energy impact tests were performed on disc-shaped specimens at velocities in the range 0.7 to 3.13 m s−1. The model predictions were evaluated by comparison of the experimental and finite element response of the falling-weight impact tests. The G'Sell–Jonas model showed much better predictability than classical elastoplasticity models. It also showed excellent agreement with experimental curves, provided stress-whitening damage observed experimentally was accounted for in the model using an element failure criterion.