Adherence of an Axisymmetric Flat Punch Onto a Clamped Circular Plate: Transition From a Rigid Plate to a Flexible Membrane

A clamped circular film is adhered to a rigid cylindrical punch. An external force pulls the punch away causing delamination at the punch-plate interface. The deflections of the film are discussed for a range of film thickness and stiffness, detailing the continuous transition from a plate under bending to a membrane under stretching. An equilibrium theory of delamination mechanics is derived based on an energy balance. A complete separation at the punch-film interface, or the “pull-off” event, is predicted when the contact circle shrinks to approximately 0.18 of the film diameter. The values and trends, presented in dimensionless normalized form here, should have implications in biological and colloidal sciences in relation to thin-walled capsules and in electronics in relation to thin encapsulating films.