Dynamic Response of Stepped Bars Subjected to Torsional Impact. Two-Dimensional Numerical Analysis and Experimental Verification.

The present work deals with the two-dimensional stress wave in a semi-infinite stepped bar of circular cross section, subjected to torsional impact. The equations governing the dynamic torsional deformation of the stepped bar are solved by the method of numerical integration along bicharacteristics. The torsional impact experiments for the stepped bar were performed using a modified torsional Hopkinson bar apparatus. The numerical results for the dynamic shear strain on the stepped bar are shown to be in close agreement with the experimental results. The distributions of the dynamic shear stresses in the vicinity of the junction of the stepped bar are examined to determine the limitations of the elementary theory of torsional wave propagation.