Senior research engineer, Mathematics Division, United States Steel Corporation, Research Laboratory, Monroeville, Pa.
In the usual method for analyzing notch toughness values only a few specific notch impact measurements are selected for experimental study. In obtaining these results, many of the experimental data are not used quantitatively. Some experimenters have used a four-parameter function, called the hyperbolic tangent, to summarize impact test data that can be assumed to follow an S-shaped pattern. The proposed method of analysis uses the parameters of this function rather than the actual impact test results to analyze changes in the notch toughness of metals. This method allows one to study the effect of the experimental variables on the shape of the entire curve rather than on one specific point on the curve. In addition, the curve parameters can be used to predict temperatures associated with any notch toughness measurement. An estimate of the variability of the prediction can also be calculated.
Paper ID: JTE11208J