Rapid Tensile Test

When we pull any object, strain is induced in it due to stress generated, and so our efforts are stored into the object in the form of strain energy. When we pull the object very slowly, during plastic deformation, this strain energy will be disicipated into heat loss and gets diffused in the object, increasing the temperature.

But if this pull force is applied rapidly, there wont be sufficient time for diffusion of energy, and the local temperature will rise corresponding to the local strain energy stored per unit volume. So the highest temperature will be where the strain energy stored is highest.

This strain energy per unit volume depends on stress and strain, but stress is uniform across the specimen, and in Tensile test we can see that in the necked region it is plastically deformed more as in the cup-cone failure. So there, in the outer periphery of necked region the Temperature rise should be highest.

I have attached some Results of Tensile test on a specimen, in ANSYS. I created a Tensile Test specimen and applied a Tensile Load on it, and Evaluated the Strain Energy in Results. As expected, we can see that in the cross sectional view of necked region, this energy in maximum at the periphery, and hence should have the maximum temperature.