Experiments on the Effect of Rate of Testing on the Criterion of Failure of Certain Mild Steels When Subject to Dynamic Torsion and Static Tensile Stresses

Abstract

Torsional impact tests have been carried out on a range of mild-steel specimens subjected in addition to various intensities of axial tensile stress. Tests have been carried out at a low speed (time to yield about 002 second) and at a high speed (time to yield about 0001 second). In each case the stresses observed are compared with those predicted by various of the criteria of failure.

With this particular type of stressing the effect of increasing the speed of the torsional component is to move the criterion of yield in a direction away from that of constant shear strain energy (Mises-Hencky) toward that of constant maximum tensile stress.

The maximum observed torsional stresses lie between the constant maximum shear stress and the constant maximum tensile stress and they are apparently unaffected by the rate of straining within the range investigated.

The angles endured to fracture diminish progressively as the axial tension is increased and they tend to be slightly reduced by an increase in speed.