Dynamic Forging of Splines and Spur Gear Forms: A Modified Upper Bound Analysis that Includes the Effects of Inertia and Some Experiments

To analyse dynamic forging of splines and spur gear forms, the upper bound solutions developed earlier for similar quasistatic cases for spline and spur gear form forging were modified suitably to take account of the inertia forces. In the experimental investigation, initially solid cylindrical billets made of tellurium lead were deformed into these shapes, i.e. splines and spur gear forms, using low velocity dropweight impact conditions and the characteristic die load–time and die movement–time results observed. From these results, the typical die load–die movement curves were evaluated in each of these cases, and compared with the estimates based on the modified analysis. Though the dynamic forging loads in each of these cases were, in general, 20%–40% higher than those observed when tested under similar quasistatic conditions, the estimated dynamic forging loads employing the modified upper bound analysis, taking account of the inertia, as given here, showed good correlations with the experiments. These and other results observed on the progressive changes in shapes of the specimens under dynamic loading conditions are given and the results commented upon.