Blister growth in layered cylinders

The problem of growth of a pre-existing "thru" delamination situated at the interface between an elastic layer and the inner surface of a rigid, possibly porous, cylinder is considered for the case of loading by applied interfacial pressure. The domain of application of the load is considered to spread with the debonded region as it propagates, and/or to spread/contract with a propagating contact zone emanating from the delamination edge, in an attempt to simulate the effects of an invasive fluid entering the debonded region via the pores of the cylinder or through some other opening to the interface. A geometrically nonlinear shallow shell theory is employed as the mathematical model of the layer and the governing differential equations, boundary and matching conditions are obtained via a variational formulation. The associated energy release rates are obtained as a consequence of the corresponding transversality conditions for the propagating delamination boundary, and the condition which defines the propagating boundary between the contact zone and a lift zone is similarly obtained. Analytical solutions are found and numerical simulations performed, revealing characteristic behavior of the evolving system. While certain of these characteristics are seen to be qualitatively similar to those observed for such systems under other types of loading, heretofore unobserved behavior is revealed for the present case. Underlying mechanisms for delamination growth in these types of systems are thus further illucidated by the results of the present analysis.