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Abstract:
Taylor impact tests in the classic and symmetric configurations were applied to analyse the development of plastic deformation and damage in Al-6082-T6 rods. Deformation histories during impact were recorded using high-speed photography, while internal axial damage was identified using metallography. The axial damage observed during the symmetric test were initiated during stress triaxiality peaks under tensile loading conditions. Variations of the stress state are the result of superimposed lateral mechanical waves reflected from the perimeter of the specimen. The fracture strain decreases with the increase of the stress triaxiality; it is thus possible to initiate damage at relatively low strain values under high-stress triaxiality values. During classic Taylor test because of the deflection of the elastic steel anvil in the rod on anvil test, the oscillations are smaller and quickly damped in comparison to the rod on rod experiment. Therefore, the initiation of axial damage is impossible. The cracks on the specimen edge are due to tensile loadings. For both the symmetric and classic Taylor tests, the damage conditions are comparable, i.e., a stable increase of strain combined with tensile loadings.

Keywords:
Taylor impact, Numerical modelling, High-speed photography, Damage initiation, Constitutive relation

Abstract:
The application of an extended Rusinek–Klepaczko constitutive equation to predict the mechanical response of 6082-T6 aluminum under the Taylor impact test conditions was presented in this article. The numerical results obtained in the study were verified through a comparison with the experimental data extracted from the Taylor anvil-on-rod impact experiments. It was concluded that the extended Rusinek–Klepaczko constitutive model predicts the behavior of the tested aluminum alloy under applied loading conditions with satisfactory accuracy. Moreover, it was found that the plastic wave phenomenon in this material is very limited and that there was no region of constant plastic wave velocity. Strain rates up to 1.6 × 104 s−1 were recorded during the Taylor impact experiments; therefore, this value may be set as the upper limit of the extended Rusinek–Klepaczko model for the alloy, which was validated with the anvil-on-rod experiment.

Keywords:
Taylor test, split Hopkinson pressure bar, direct impact compression test, 6082-T6 aluminum alloy, plastic wave propagation

Abstract:
In this paper original experimental methodologies of dynamic plastic behavior of various structural materials in a wide range of strain rates up to 10 5 s - 1, and at selected temperatures are presented. Identification of constitutive models and their verification are also included