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This work examined the effect of shock loading kinetics on the early stages of damage evolution in Cu samples. The tensile loading characteristics were tailored by controlling the geometry and material used for the flyer plates in the plate impact experiments. All the Cu specimens used in this study had similar microstructures with an average grain size of 100μm. This work has shown that the interplay of the energy supplied by the shock impulse and the time spent in its dissipation seem to be responsible for the characteristics of the resultant damage fields. For an increasing value in the coupled parameter of energy*time, the damage fields appear to evolve from the early stages of damage, in the form of void nucleation and initial void growth, to the void coalescence stage. In this regard, a damage field consisting of well-coalesced voids, which created a nearly complete fracture surface, was observed for the highest value of energy*time. Additionally, a framework is postulated in which damage development can be predicted from the real-time, continuum level response measurements, i.e. free surface velocity. Under this framework, good agreement between the characteristics of the free surface velocities and the predicted, as well as the experimentally observed, damage fields is found. |
