MATERIALS-TRUE STRESS-TRUE STRAIN CURVES-DETERMINATION OF

Bars were tested in a 60,000 lb. Baldwin universal test machine using a KSMD extensometer and an MA-1 microformer recorder. For Mg the magnification to the yield point was 500X and for all of the other specimens the magnification was 250X to yield. The load was then removed and the magnification was reduced to 20X for the test to failure. Initial and final diameters were recorded. The method of MacGregor was used to determine true stress-true strain relationships. Values for true stress and true strain were computed from the test data using the following relationships True strain 1n 1 e, e Nominal strain. True stress P 1 eA,P Measured load, A Original area E ACH TRUE STRESS-TRUE STRAIN CURVE PRESENTED WAS DETERMINED FROM THE RESULTS OF ONE SPECIMEN. The results are empirical. Author