EURODYMAT 2000 - 6th International Conference on Mechanical and Physical Behaviour of Materials under Dynamic Loading

J. Phys. IV France 10 (2000) Pr9-149-Pr9-154
DOI: 10.1051/jp4:2000925

Dynamic tensile testing of sheet metal

P. Mouro¹, G. Gary² and H. Zhao<sup>3

1</sup>  PSA, Peugeot-Citroën, Direction of Research and Innovation, chemin de la Malmaison, 91570 Bièvres, France
²  Laboratoire de Mécanique des Solides, École Polytechnique, 91128 Palaiseau cedex, France
³  Laboratoire de Mécanique et Technologie – Cachan, Université Pierre et Marie Curie Paris 6, 61 avenue du Président Wilson, 94235 Cachan cedex, France

Abstract
The testing of sheet metal at high strain rates requires the use of the SHPB set-up. This technique provides satisfactory results as far as the compression and shear are concerned. A modified SHPB set-up is presented here, which extends the scope of this technique to the tensile loading of sheet metals. In this case, many measurement problems arise due to the way in which the specimen is connected to the bars, which never completely prevents unexpected slipping and is liable to induce interference waves due to an impedance mismatch. The technique described here was based on the "hat specimen" technique proposed by Lindholm [l]. A two-dimensional "hat shaped" specimen is subjected to compression loading. A tensile state is induced in a symmetrically necked area, where higher strains are concentrated. Connecting supports of an appropriate shape are attached to the bars. They have the same impedance as that of the bars to avoid the occurrence of any interference waves. The "hat" shape prevents sliding, and to ensure perfect initial contact conditions, the complete system is elastically pre-stressed. A special method of wave analysis is then used to determine the forces and displacements occurring at the specimen ends from the strain signals recorded in the bars.

© EDP Sciences 2000