Device for joining two tubular pieces of an aircraft jet engine

The coupling for two tubular components (11, 12), one being an acoustic protection component with an inner permeable skin, an outer impermeable skin and a cellualr core between them, and the other having an end flange (16), has a rigid ring (31) of approximately S-shaped cross-section located and fixed in a cavity (32) in the core. The ring is held in place by fastenings (34) that join a flanged ring to the end of the acoustic component, the ring being connected by its flange (28) to the flange (16) of the first tubular component (12).