The effect of strain rate of dynamically loaded copper on temperature accumulation

Abstract
A new experimental "escaping bar" technique is proposed for studying the dynamical behavior of copper at strain rates in the range from 500 to 1000 s ^-1 using a modified split Hopkinson pressure bar (SHPB). The conventional Hopkinson pressure bar consists of an incident bar and a transmitted bar. In the experimental facility used in this study, the transmitted bar was made shorter than the incident bar. Thus modified, the transmitted bar acted as an escaping bar, which allowed us to transport a specimen through a receiver into a calorimeter over a short period of time. Experiments were performed on copper specimens subjected to a single loading pulse multiple times at the same velocity of a striker. Ihe adiabatic conditions of the deformation process enabled one to measure temperature changes in a specimen. Using this technique, it is possible to evaluate the amount of the heat released during deformation and the value of energy remained in the material structure. A 3D Surface Profiler New View 5000 was used to examine the specimen microstructure.