Method of fabricating an airfoil element out of composite material and having metal reinforcement fastened by riveting

1. A method of fabricating an airfoil element out of composite material, the method comprising:

making a fiber preform, said preform being impregnated with resin;

polymerizing the resin with a matrix so as to obtain an airfoil element made of composite material comprising fiber reinforcement densified by a matrix; and

fastening metal reinforcement on the composite material airfoil element, the metal reinforcement being fastened on the airfoil element by rivets;

wherein the method further comprises, prior to impregnating the fiber preform with resin, inserting at least one spacer element between the fibers of the fiber preform and removing said at least one spacer element after the resin has been polymerized so as to form at least one passage between the fibers of the fiber reinforcement of the composite material airfoil element, and

wherein the method further comprises impregnating the fiber preform with the resin by injecting the resin into the fiber preform when the at least one spacer element is inserted between the fibers of the fiber preform.

2. The method according to claim 1 , wherein the at least one spacer includes at least one insert corresponding to the dimensions of a passage for the shank of a rivet is inserted between the fibers of the fiber preform, the insert being removed or eliminated after the resin has been polymerized in order to form a passage suitable for receiving the shank of a rivet in the composite material airfoil element.

3. The method according to claim 2 , wherein each insert is removed from the composite material airfoil element by mechanical means.

4. The method according to claim 2 , wherein the at least one insert is removed from the airfoil element by machining the at least one insert.

5. The method according to claim 2 , further comprising, after the polymerizing the resin and prior to the fastening the metal reinforcement, removing the airfoil element from a mold in which the polymerizing takes place, and then removing the at least one insert from the airfoil element.

6. The method according to claim 1 , wherein, prior to polymerizing the resin, a fiber texture that is to form the fiber preform is placed in the mold cavity of shaping tooling, said cavity including the at least one spacer, the at least one spacer including at least one tooth or spike serving to form at least one passage between the yarns of the fiber texture, the resulting fiber preform being maintained in the mold cavity during polymerization of the resin.

7. The method according to claim 1 , wherein the fiber preform is obtained from a fiber texture made by three-dimensional or multilayer weaving, the preform subsequently being impregnated with a resin.

8. The method according to claim 1 , wherein the airfoil element corresponds to a turbine engine blade.

9. The method according to claim 8 , wherein the turbine engine blade is an aeroengine fan blade.

10. The method according to claim 1 , wherein the polymerizing the resin includes heating the resin.

11. The method according to claim 1 , wherein the resin is a thermosetting resin and the polymerizing includes heating the thermosetting resin.

12. A method of fabricating an airfoil element out of composite material, the method comprising:

making a fiber preform, said preform being impregnated with resin;

polymerizing the resin with a matrix so as to obtain an airfoil element made of composite material comprising fiber reinforcement densified by a matrix; and

fastening metal reinforcement on the composite material airfoil element, the metal reinforcement being fastened on the airfoil element by rivets;

wherein the method further comprises, prior to impregnating the fiber preform with resin, inserting at least one spacer element between the fibers of the fiber preform and removing said at least one spacer element after the resin has been polymerized so as to form at least one passage between the fibers of the fiber reinforcement of the composite material airfoil element,

wherein the at least one spacer includes at least one insert corresponding to the dimensions of a passage for the shank of a rivet is inserted between the fibers of the fiber preform, the insert being removed or eliminated after the resin has been polymerized in order to form a passage suitable for receiving the shank of a rivet in the composite material airfoil element, and

wherein the at least one insert is removed from the airfoil element by machining the at least one insert.

13. A method of fabricating an airfoil element out of composite material, the method comprising:

making a fiber preform, said preform being impregnated with resin;

polymerizing the resin with a matrix so as to obtain an airfoil element made of composite material comprising fiber reinforcement densified by a matrix; and

fastening metal reinforcement on the composite material airfoil element, the metal reinforcement being fastened on the airfoil element by rivets;

wherein the method further comprises, prior to impregnating the fiber preform with resin, inserting at least one spacer element between the fibers of the fiber preform and removing said at least one spacer element after the resin has been polymerized so as to form at least one passage between the fibers of the fiber reinforcement of the composite material airfoil element,

wherein the at least one spacer includes at least one insert corresponding to the dimensions of a passage for the shank of a rivet is inserted between the fibers of the fiber preform, the insert being removed or eliminated after the resin has been polymerized in order to form a passage suitable for receiving the shank of a rivet in the composite material airfoil element, and

where the method further comprising, after the polymerizing the resin and prior to the fastening the metal reinforcement, removing the airfoil element from a mold in which the polymerizing takes place, and then removing the at least one insert from the airfoil element.