Response of thick composite rings under uniform external pressure

Abstract

The investigation reported herein is concerned with examining, via an experiment, the response of thick hoop wound AS4/PPS and S-2 Glass/ Epoxy rings subjected to external hydrostatic pressure. A custom pressurization testing chamber was manufactured for this purpose. Two different methods of applying the pressure was examined. In the first of these methods, constrained ring buckling (mode three) was observed in the initial stages of the test as the specimen was constrained from motion by the rubber membrane used to seal the hydraulic pressure. In the second type of loading method, unconstrained ring buckling (mode two) was observed. Microscale failure initiators such as fiber kinking or delamination between plies was visible in the rings that were unloaded upon buckling. A one dimensional shear deformation theory and a two dimensional elasticity theory were employed to examine the buckling and initial postbuckling behavior of the tested rings. Good agreement between experiment and theory is noted. The details of the analytical work pertaining to the ring buckling analysis is reported elsewhere.