Method for attaching a non-metal component to a metal component

#1. Technical Field

#The present invention relates to gas turbine engine fasteners and, more particularly, to gas turbine engine fasteners for attaching components fabricated from dissimilar materials.

#2. Background Art

#FIG. 1 is a schematic depiction of a gas turbine engine;

#FIG. 2 is a schematic side elevational view of a divergent flap and an external flap of the gas turbine engine of FIG. 1;

#FIG. 3 is a schematic side elevational view of the divergent flap of FIG. 2 with a plow portion shown in cross-section;

#Referring to FIG.1, a gas turbine engine 10 includes a compressor 12, a combustor 14, and a turbine 16 centered around a central axis 17. Air 18 flows axially through the engine 10. As is well known in the art, air 18 is compressed in the compressor 12. Subsequently, the compressor air is mixed with fuel and burned in the combustor 14. The hot gases expand generating thrust to propel the engine 10 and to drive the turbine 16, which in turn drives the compressor 12. The exhaust gases from the turbine 16 exit through the exhaust nozzle 20.

#Referring to FIG. 2, the exhaust nozzle 20 includes a plurality of external flaps 24 arranged circumferentially about the axis 17 and a plurality of divergent flaps 26 disposed radially inward from the external flaps. Each external flap 24 includes an external flap surface 28 having a particular geometry. Each divergent flap 26 includes a fore portion 30 and an aft portion 32. The fore portion 30 includes a hinge assembly 36 for securing the divergent flap 26 to the gas turbine engine. The divergent flap 26 further comprises a hotsheet 38 extending the length of the flap 26 from the fore portion 30 to the aft portion 32, a backbone structure 40 disposed radially outward of the hotsheet 38 and secured thereto by means for attachment 42, and a plow portion 46 disposed in the aft portion 32 of the divergent flap 26 and secured to the backbone structure 40 by a plow fastener assembly 48, shown in FIGS. 3-10.

#Referring to FIGS. 3 and 4, in the preferred embodiment of the present invention, the hotsheet 38 comprises a substantially flat substrate fabricated from ceramic matrix composite (CMC) having a hotsheet inner side 50 exposed to the exhaust gases 18 and a hotsheet outer side 52 facing the backbone structure 40. The hotsheet inner side 50 and the hotsheet outer side 52 extend from the fore portion 30 to the aft portion 32 and include a hinge edge 56 and a trailing edge 58. In the preferred embodiment, the trailing edge is defined by a chamfered surface 60. The hotsheet 38 also includes a plurality of attachment openings 61, as best seen in FIG. 4. The openings 61 also include a countersink hole 62 formed within the hotsheet inner side 50, as best seen in FIG. 11.