Crack Propagation and Its Shear Mechanisms in the Bovine Descending Aorta.

Aortic dissection and rupture may involve circumferential shear stress in the circumferential-longitudinal plane. Inflation of bovine descending aortic ring specimens provides evidence of such shear from the non-uniform circumferential distortion of radial lines drawn on the circumferential-radial ring face. Delamination without tensile peeling induces cracks that propagate nearly circumferentially in the circumferential-longitudinal plane from the root of a radial cut representing rupture initiation in a ring.