An Investigation of the <i>I</i> and <i>dJ/da</i> Concepts for Ductile Tearing Instability

Abstract

Unstable ductile tearing was found in a series of tests on notched bend-bars of HY130 steel tested in a screw-driven machine. R-curves were measured and ductile tearing stability analyzed according to the energy rate, I, and dJ/da tangency concepts. The effect of compliance on the energy rate available and an appropriate estimation of work dissipation rate for the I theory are described. The dJ/da concept is used in both its “exact” form and as originally stated in terms of T, with certain compliance terms modified. Subject to choice of appropriate compliance terms, the experimental behavior is predicted satisfactorily by both I and dJ/da methods, although the restriction of this analysis to a configuration very similar to that on which the R-curve was measured must be recalled.