Non-linear flexure testing of a high-strength glass disk

Strength measurements of glass disk substrates were made by ring-on-ring flexural testing. The non-linear problem of a disk undergoing a large deflection in ring bending was solved approximately by a variational method. The solution has the minimum total energy and satisfies the required boundary conditions. Deflection, stress and strain distributions are evaluated as functions of the external load in terms of seven parameters related to sample material and geometry. Good agreement between experiment and theory has been obtained without any adjustable parameter for a glass disk of Corning Code 0313.