Identification of plastic behaviour of sheet metals in high strain rate tests

In this work, dynamic tension tests have been conducted by an SHB on sheet metals in order to characterize the plastic behaviour of the materials. First of all, the sample geometry and the clamping system were optimized by FEM simulations in order to: (i) reduce impedance disturbance due to the fasteners, (ii) maximize the specimen cross-section to increase the force measurement sensitivity, (iii) reduce the elongation measurement errors due to deformation of the clamping system. Pictures of the samples were acquired during the test by means of a fast camera. On the one hand, this permitted to validate the strain measurement by the classical SHB theory formulas; on the other hand, application of DIC method permitted to obtain the actual strain distribution maps. These strain maps have been used to extract the parameters of a strain hardening constitutive model.