Validation of material model for polypropylene (PP)

Abstract

Polymers are the up and coming engineering material. The number of possibleapplications is increasing fast and so is the need for a good polymer material model. Thescientists at SIMLab at NTNU have developed such a material model. In this thesis is thematerial model calibrated to represent an impact modified polypropylene used by Toyota.The validation started with the calibration. A review of the theoretical background of thematerial model and a detailed explanation of the calibration procedure are given todescribe the derivation of the calibrated material model. The model is then applied in FEsimulationsof the material tests and the two validation tests. The first validation test is aquasi-static tension test using a specimen with a centric hole. This test resembles thematerial tests but the centric hole makes the load response slightly more complex. Theother test is an impact test using a drop tower. This test validates the material modelsability to represent dynamic problems and also tests the representation of the strain ratedependency.The material model proves that it is capable of representing all the tests in this thesis quite accurately.