On the detachment of step-tapered doublers : Part 1—foundations

One!dimensional edge debonding of layerwise step!tapered patches from both ~at and cylindrical struc! tures is examined[ The problems are approach from a uni_ed point of view\ as propagating boundary problems in the calculus of variations\ with the models for both ~at and curved structures being formulated simultaneously[ The e}ects of a contact zone adjacent to the bonded region are incorporated as is the phenomenon of edge!point contact[ The formulation results in a selfconsistent representation of the various intact and debonded segments of the composite structure comprised of a multilayer patch and a base structure[ It concurrently yields the conditions which establish the locations of the propagating boundary of the bonded "intact# region\ and the propagating boundary of the contact zone[ The former condition yields the selfconsistent and physically interpretable expressions for the corresponding energy release rates for debonding[ The conditions governing edge!point contact are likewise established[ Three types of loading conditions are considered ] "i# in!plane:circumferential tension\ "ii# three!point transverse loading\ and "iii# applied transverse "internal# pressure[ It is shown analytically\ within the context of the mathematical models employed for both ~at and curved structures\ that of the loading types considered the third admits a contact zone for certain common conditions of the supports[ Results of numerical simulations\ based on analytical solutions\ pertaining to the test con_gurations of ~at structures subjected to applied in!plane tension and three!point transverse loading are presented for various taper angles and compared