Buckling phenomena in double curved cold-bent glass

Double curved anticlastic glazed surfaces are widely used for free-form façades and roofs of modern buildings. An effective technique consists in cold bending rectangular glass plies by twisting them with forces applied at the corners. The linear Kirchhoff-Love theory predicts that the deformed shape is a hyperbolic paraboloid, which preserves the straightness of the edges. However, experiments have provided evidence that a particular form of instability occurs above a certain limit of the distortion: one of the principal curvatures becomes dominant with respect to the other, the plate bulges into an asymmetric configuration and the edges are not any more straight. Here, a simple model is presented that, using a modified version of Mansfield׳s inextensional theory for thin plates, is able to interpret this phenomenon. Results are in good agreement with numerical experiments using large deflection theory. Moreover, the possibility of increasing the limit of the stable configuration by stiffening the edges is investigated.