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 δn, crack tip opening angle ψc, crack mouth opening angle αs, energy dissipation rate R, and specific work of fracture As. Our experimental results demonstrate that the values of δn, ψc, αs, R, and As 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 αs and As is more preferable over the use of δn, ψc, and R values for a number of basically important reasons discussed in this paper.