A Study to Improve the Crash Performance of Plastic Materials Considering the Strain Rate and Fracture Characteristic

Abstract

The numerical simulation of structural parts made from plastics is becoming increasingly important nowadays. The fact that almost any structural requirement can be combined in a lightweight, durable and cost effective structure is the driving force behind its widespread application. More and more structural relevant parts are being constructed and manufactured from plastics. It is difficult accurately to predict the reliability according to finite element analysis, because plastics materials show the complex material behaviour. Thus, it is demanded for reliable and obvious methods to design these parts and to predict their material behaviour. For the finite element simulations of polymeric materials mathematical models are needed which cover all the phenomena of the material. In this paper, it is possible to describe accurately the mechanical behaviour of thermoplastic materials using a new constitutive model termed as SAMP-1(Semi- Analytical Model for Polymers) in LS-dyna. We performed the high speed tension tests (strain rate: 0.001/s, 0.1/s, 1/s, 50/s, 100/s) for the characterisation of the plastics material. Also, the parameters of the SAMP-1 model were identified by using multidirectional mechanical tests such as uniaxial tension, simple shear, and compression tests. As validation purpose, the SMAP-1 model was compared to the existing models for predicting the stress-strain behaviour in the test specimens and the dynatup impact test.