OPPOSITE PATHS IN THE TEARING OF SHEET MATERIALS

It is a matter of everyday experience that sheet material - such as al uminium foil and adhesive tape fails to tear evenly but yields ones th at converge to a point. Tn small matters this is merely irritating, bu t it can be of major engineering importance: for example, in damage to an aircraft's fuselage or a ship's hull. This article reviews the mec hanics of the process, using the concept of least work.