A Study of beak geometries for achieving pure shear deformation in folding-shearing

Abstract. The automotive industry produces significant material waste from the deep drawing process. The Folding-shearing process was developed as a solution that involves folding a blank while collecting the excess material in a region called the ‘beak’. The beak is then sheared in-plane to form the part without any thickness changes. Previous work used folding-shearing to form a quarter of a square based cup and half of a U-channel part; however, these parts suffered from high levels of thickening in the sheared region. This study, for the first time, explores the underlying design principles to improve the thickness distribution by introducing curvature to the beak perimeter to induce compressive strains in one direction and tensile strains in the other. Numerical simulations are validated using physical trials and show a reduction in thickening from 17.5% to 6%.