A method of obtaining strain distributions of circumferentially notched cylindrical bars by means of a hardness test.

Abstract

Plastic strain distributions on the net section of circumferentially notched cylindrical specimens are obtained using the Vickers microhardness test and numerical calculation. Notched specimens were loaded up to 0.7 Pmax (Pmax : maximum tensile load), 0.8Pmax, 0.9Pmax, 0.95Pmax, Pmax, 0.98Pmax beyond Pmax and 0.95Pmax beyond Pmax. Strains at a point were calculated by making an assumed curve of radial displacement touch at that point to the real curve of radial displacement distribution obtained from the hardness number distribution. The distributions of the equivalent and axial plastic strains are concave at all load levels tested. The equivalent plastic strain is a little greater than the axial plastic strain. The magnitude of the equivalent and axial plastic strains at the notch root at Pmax is about twice as large as the axial plastic strain at Pmax of unnotched specimen.