Materials insight

A Constitutive Formulation for Polymers Subjected to High Strain Rates

"Reliable prediction of the behavior of structures made from polymers is a topic under considerable investigation in engineering practice. Especially, if the structure is subjected to dynamic loading, constitutive models considering the mechanical behavior properly are still not available in commercial finite element codes yet. In our paper, we present a new constitutive law for polymers which recovers important phenomena like necking, crazing, strain rate dependency, unloading behavior and damage. In particular, different yield surfaces in compression and tension and strain rate dependent failure, the latter with damage induced erosion, is taken into account. All relevant parameters are given directly in the input as load curves, i.e. time consuming parameter identification is not necessary. Moreover, the models by von Mises and Drucker-Prager are included in the description as special cases. With the present formulation, standard verification test can be simulated successfully: tensile and compression test, shear test and three point bending tests."

S. Kolling, A. Haufe, M. Feucht, P.A. Du Bois
 

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About the author

Paul Du Bois

Paul Du Bois has worked as an independent consultant in the field of industrial application of large scale numerical simulations since September 1987. He has specialized in the application of explicit integration techniques for crashworthiness and impact problems.

Among Paul’s customers are most of the world’s automotive assemblers such as Daimler, GM, Ford, Opel, Fiat, Porsche, Volvo, PSA, Renault, Toyota, Nissan, Honda, Hyundai and many others including automotive suppliers and design and engineering companies. Paul’s more recent projects include a Daimler sponsored development of a generalized plasticity law for the simulation of plastics and the formulation of a tabulated hyper-elastic material law with damage for the simulation of rubber and foam.

He was involved with the joint research organization of the German automotive industry, FAT, in the working groups: ‘Side Impact Dummies’ from 1992 through 1997 and ‘Foam Materials’ (1996 until 2009). In 2003, Paul was asked by LSTC to perform a training mission at the Russian national laboratory in Snezinskh.