Engineering assessment of ductile tearing in uniaxial and biaxial tension

To decide between clearly different approaches for engineering assessment of plane stress tearing, we performed uniaxial and biaxial tensile tests on middle-cracked specimens at various in-plane constraint states. Attention was focused on determination of the crack tip opening spacing sigma(n), crack tip opening angle psi(c), crack mouth opening angle as, energy dissipation rate R, and specific work of fracture A(s). Our experimental results demonstrate that the values of delta(n), psi(c), alpha(s), R, and A(s) for a high-strength low-hardening aluminium alloy all depend on the specimen geometry, its size, and the load biaxiality ratio. However, assessment of ductile tearing by interconnected characteristic quantities a, and A, is more preferable over the use of delta(n), psi(c), and R values for a number of basically important reasons discussed in this paper. (c) 2005 Elsevier Ltd. All rights reserved.