Comparison of analytical techniques employed to reduce the data obtained for steel samples subjected to high ambient pressure and axial tension

This report reexamines some of the experimental data collected by P.W. Bridgman and published in his book ‘Studies in Large Plastic Flow and Fracture’. Of special concern, for the present considerations, is the problem of the flow and resultant ‘necking’ which occurs when a cylindrical bar of steel is subjected to high ambient pressures and axial tension. Bridgman developed an equation which corrected the average stress across the minimum cross-section of the ‘necked’ portion of the sample for the effects of plastic stress concentration. A subsequent analysis by one of the present authors offered another relation for the stress concentration which provided a more complete theoretical analysis of the problem. This report documents the statistical evidence that the new procedure provides a superior correlation to Bridgman's data than Bridgman's original analysis.