AN ADHESIVE ASSEMBLY METHOD AND AN ADHESIVE ASSEMBLY OBTAINED BY THE METHOD

Abstract

A method of adhesively bonding a first substrate on a second substrate in an adhesive bonding zone by an adhesive joint integrating a support mesh, wherein surplus adhesive joint is folded over onto one or the other of the first or second substrates so that the support mesh is present over the entire adhesively bonded zone after curing.

Claims

1. A method of adhesively bonding a first substrate on a second substrate in an adhesive bonding zone by means of an adhesive joint integrating a support mesh, the method comprising folding over a surplus adhesive joint onto one or the other of the first or second substrates so that the support mesh is present over an entire adhesively bonded zone after curing.

2. The adhesive bonding method according to claim 1, wherein the retention of the folded-over surplus adhesive joint is strengthened by mechanical pressure from a vacuum bag or from an appropriate retention fixture.

3. The method according to claim 1, wherein the surplus adhesive joint beyond the adhesive bonding zone has a length of less than 20 mm.

4. The method according to claim 1, wherein a surface of the first or second substrates that is to receive the surplus adhesive joint is previously prepared to facilitate eliminating that surplus.

5. The method according to claim 4, wherein the surface of the substrate that is to receive the surplus adhesive joint is prepared by depositing a peel-off fabric or an adhesive tape made of Teflon on at least a portion of the surface of the substrate.

6. The method according to claim 1, wherein the adhesive is an epoxy adhesive and the support mesh is a mesh made of nylon or of elastomer.

7. The method according to claim 6, wherein the first substrate is metal structural reinforcement and the second substrate is a leading edge of an aircraft turbine engine fan blade made of fiber reinforced organic matrix composite material.

8. An adhesively bonded assembly of a first substrate on a second substrate by means of an adhesive joint integrating a support mesh, wherein the support mesh is present after curing over the entire adhesively bonded zone between the first and second substrates.

9. The adhesively bonded assembly according to claim 8, wherein the adhesive is an epoxy adhesive and the support mesh is a mesh made of nylon or of elastomer.

10. The adhesively bonded assembly according to claim 8, wherein the first substrate is metal structural reinforcement and the second substrate is a leading edge of an aircraft turbine engine fan blade made of fiber reinforced organic matrix composite material.

11. The aircraft turbine engine fan blade including an adhesively bonded assembly according to claim 10.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other characteristics and advantages of the present invention appear from the following description made with reference to the accompanying drawings, which show an implementation having no limiting character, and in which:

[0018] FIG. 1 is a simplified diagram with a detail view showing an adhesively bonded assembly in accordance with the invention in its vacuum bag;

[0019] FIG. 2 shows the adhesively bonded assembly once the surplus adhesive joint has been eliminated; and

[0020] FIG. 3 shows a prior art adhesively bonded assembly in its vacuum bag.

DESCRIPTION OF EMBODIMENTS

[0021] FIG. 1 shows an adhesively bonded assembly in accordance with the invention arranged in its vacuum bag 40 that is to be subjected to pressure (arrows 44) from the autoclave. This assembly 10 of a first substrate 12 on a second substrate 14 by means of an adhesive joint 16 integrates a support mesh 18, as described above with reference to FIG. 1. The first substrate has an outer surface 12A and an inner surface 12B, and the second substrate also has an outer surface 14A and an inner surface 14B, these two substrates being bonded together via their inner surfaces.

[0022] The assembly of the invention differs from prior art assemblies in that the adhesive joint that is in the form of an adhesive film is folded over one of the two substrates (the first substrate 12 in the example shown, but that should not be considered as being limiting), with the film being held against the outer surface 12A by the adhesive joint itself, with this being strengthened by the mechanical pressure from the vacuum bag 40 in the event of curing in an autoclave or by pressure from an appropriate retention fixture (not shown) when the adhesive is used cold outside an autoclave.

[0023] This folding is advantageously performed over a length of substrate that is typically less than 20 mm. The adhesive is typically an epoxy adhesive and the support mesh is a mesh of nylon or of elastomer.

[0024] Once the adhesive has set cold or has been cured in the autoclave, the surplus adhesive joint on the adhesively bonded assembly can then be eliminated. This elimination is made easier by the fact that the outer surface 12A of the first substrate is previously prepared by adding an adhesive tape made of Teflon or a peel-off fabric 20 at least over the portion that is to receive the surplus.

[0025] As shown in FIG. 2, which shows the adhesively bonded assembly once the surplus adhesive joint has been removed, folding the adhesive joint over the outer surface of the substrate in this way serves to guarantee that support is present over the entire adhesively bonded zone between the two substrates, with the shrinkage zone 22 in the support mesh thus being offset beyond the adhesively bonded zone, to the end of the adhesive joint in its portion that is thus eliminated.

[0026] As a result of multiple tests with various types of support mesh and cutting up parts, the inventors have also been able to show that the surplus adhesive joint folded over onto the substrate has no impact on the distribution of pressure during curing and is therefore not of a nature that might reduce the final mechanical properties of the adhesive bonding.

[0027] A particular application to the invention lies in aircraft turbine engine fan blades, and more precisely in adhesively bonding metal structural reinforcement onto the leading edges of such fan blades, which are themselves made of fiber reinforced organic matrix composite material, given that such edges are greatly stressed in the event of impacts against objects. It is therefore essential to guarantee the quality of the adhesive bonding of the reinforcement, and this is well ensured by the invention.