Fracture Mechanics of a Shaft-loaded Blister Test - Transition from a Bending Plate to a Stretching Membrane

A linear elastic solution is proposed for a circular disc in transition from a plate-like (pure bending) to a membrane-like behavior (pure stretching) under a central point load. The strain energy release rate for film delamination is found to be G = χ(Pw₀/πa²) with χ a numerical constant varying from 1/2 for a plate-like disc to 1/4 for a thin flexible membrane.