High strain rate testing of aluminium alloy & high speed photography

Abstract
In order to gain in safety, it is necessary to study material responses in severe conditions, for instance under dynamic loadings, especially in the case of light alloys used in car, nautical and aeronautical industries. The initiated study concerns fatigue-impact coupling effects on a commercial aluminium alloy (AA5454) used in car industry. Through a part of this investigation, by modificating the pre-existent flywheel, we try to characterize its dynamic strain and failure properties. The first modification is the changing of the specimen holding device, using a new measurement technique, inspired by the Split Hopkinson Pressure Bar. This allows us to obtain data directly exploitable for the derivation of the intrinsie material behaviour, avoiding then a numerical post treatment. Furthermore, we present the multi-CCD camera system that we set up in addition to the flywheel apparatus. This photographie device is associated to this equipment in order to visualize localisation of plastic strain and subsequent failure phenomenon.