Citation

Pyttel T, Weyer S. Int. J. Crashworthiness 2003; 8(5): 433-442.

Copyright

(Copyright © 2003, Informa - Taylor and Francis Group)

DOI

unavailable

PMID

unavailable

Abstract

During the past two decades explicit Finite Element codes have become an indispensable tool for crashworthiness analysis and the design of passenger safety systems. While these codes are reliable for the prediction of ductile metal structures, there are many open questions for glassy polymers. Glassy polymers are being increasingly applied in components critical for passenger and pedestrian safety. This was the motivation for the development of an appropriate material model for these materials. The constitutive model presented in the paper is based on experimental investigations of tensile coupon tests. These tests were performed at different temperatures and with different velocities. The first part of the paper outlines the principal behaviour of glassy polymers and some fundamental differences to metals. The second part presents the constitutive model implemented in PAM-CRASH. This model has two features which distinguish it from standard elasto-plastic models. First the temperature is included and second the stress-strain curve is described with an appropriate function. A separate section describes the identification of the parameters of the model. In order to assess the performance of the model, an experiment with a structure used in automotive A-pillars was performed. A sphere - similar in size and weight to a human head - impacted a honeycomb plate made of BAYBLEND (a special kind of glassy polymer used at BMW) at different temperatures and with different velocities. For the simulation of this experiment the material model presented in this paper was used. Experiment and simulation results show good agreement for the whole range of temperatures and velocities.

Language: en