METHOD FOR REPAIRING A PART FOR AN AIRCRAFT TURBINE ENGINE

Abstract

A method for repairing a part for an aircraft turbine engine, the part including a lower panel, an upper panel and a core having a honeycomb structure arranged between the lower panel and the upper panel, the part having an unimpaired portion and an at least partially impaired portion, the repair method including the following steps: (a) removing at least one portion of the lower panel or the upper panel from an area to be repaired; (b) removing at least one portion of the core from the area to be repaired; (c) reforming the core in the area to be repaired directly on the part by additive manufacturing; (d) reforming the lower panel or the upper panel in the area to be repaired, directly on the part.

Claims

1. A method for repairing a part for an aircraft turbine engine, the part comprising a lower panel, an upper panel, and a core having a honeycomb structure arranged between the lower panel and the upper panel, the part comprising an unimpaired portion and an at least partially impaired portion, the repair method comprising the following steps of: (a) removing at least one portion of the lower panel or upper panel from an area to be repaired; (b) removing at least one portion of the core from the area to be repaired; (c) reforming the core in the area to be repaired directly on the part by additive manufacturing; (d) reforming the lower panel or the upper panel in the area to be repaired directly on the part.

2. The method according to claim 1, wherein the step (c) comprises the following substeps of: (c1) providing a digital model comprising spatial coordinates of the unimpaired portion of the core; (c2) supplying a first repair material to an additive manufacturing device, this device comprises a nozzle; and (c3) depositing the first repair material according to the spatial coordinates acquired in step (c1) to reform the core.

3. The method according to claim 2, wherein the core is formed of a material identical to the first repair material.

4. The method according to claim 2, wherein the first repair material is selected from metallic materials such as aluminium.

5. The method according to claim 1, wherein the lower panel and/or the upper panel comprises a plurality of plies.

6. The method according to claim 1, wherein the step (b) of removing at least one portion of the core is carried out according to a profile in a cross-section of the part in the form of an ellipse, the ellipse having a minor axis (Y) and a major axis (X).

7. The method according to claim 6, wherein the nozzle is cylindrical and in that the ellipse has a height measured along the minor axis (Y) greater than or equal to the radius of the nozzle; wherein the step (c) comprises the following substeps of: (c1) providing a digital model comprising spatial coordinates of the unimpaired portion of the core; (c2) supplying a first repair material to an additive manufacturing device, this device comprises a nozzle; and (c3) depositing the first repair material according to the spatial coordinates acquired in step (c1) to reform the core.

8. The method according to claim 7, wherein the ellipse has a width measured along the major axis (X) greater than or equal to twice the radius of the nozzle.

9. The method according to claim 2, wherein the honeycomb structure has a plurality of cells, the cells being separated by a distance D, the nozzle having a diameter greater than or equal to twice the distance D.

10. The method according to claim 1, wherein the lower panel and the upper panel are made of a composite material.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0031] Further characteristics and advantages will be apparent from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[0032] FIG. 1 is a cross-sectional view of an example of a part;

[0033] FIG. 2 is a cross-sectional view of the part in FIG. 1 to be repaired;

[0034] FIG. 3a is a cross-sectional view of the part of FIG. 2 in a first step of the method according to the invention;

[0035] FIG. 3b is a top view of FIG. 2;

[0036] FIG. 4 is a cross-sectional view of the part of FIG. 2 in a second step of the method according to the invention;

[0037] FIG. 5a is a cross-sectional view of the part of FIG. 2 in a third step of the method according to the invention;

[0038] FIG. 5b is a top view of FIG. 5a;

[0039] FIG. 6a is a cross-sectional view of the part of FIG. 2 in a third step of the method according to a first example;

[0040] FIG. 6b is a cross-sectional view of the part of FIG. 2 in a third step of the method according to a second example;

[0041] FIG. 7 is a cross-sectional view of the part of FIG. 2 in a fourth step of the method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0042] FIG. 1 shows a cross-sectional example of a part 1 according to the invention. The part 1 is intended to equip an aircraft turbine engine. The part 1 is for example an acoustic panel.

[0043] The part 1 comprises an upper panel 2, a lower panel 3 and a core 4 arranged between the upper panel 2 and the lower panel 3.

[0044] The upper panel 2 and the lower panel 3 have a thickness of between 0.1 mm and 15 mm respectively. The upper panel 2 and/or the lower panel 3 are made of a composite material. The upper panel 2 and/or the lower panel 3 comprise for example a plurality of plies 2a, for example between 2 and 15 plies. The plies 2a represent formed layers of the composite material. In the example shown in FIG. 1, the lower panel 3 comprises a single ply 2a.

[0045] The composite material comprises an organic matrix and reinforcing fibres embedded in the matrix. For example, the matrix is made of a thermoplastic or thermosetting polymeric material. The thermosetting polymeric material is for example an epoxy resin. The reinforcing fibres are for example carbon fibres.

[0046] The core 4 is arranged between the upper panel 2 and the lower panel 3. The core 4 has a thickness greater than the thickness of the upper panel 2 and the thickness of the lower panel 3. The thickness of the core 4 is for example between 5 mm and 20 mm. The core 4 has a honeycomb structure. The honeycomb structure is made of a material selected from metallic materials such as aluminium. According to another example of embodiment, the honeycomb structure is formed from a material selected from polymeric materials such as polypropylene or aromatic polyamides. The honeycomb structure has a plurality of cells 4a. The cells 4a have a tubular shape with a hexagonal cross-section for example. The cells 4a are separated by a distance D of between 1 mm and 20 mm.

[0047] In operation, the part 1 is subject to high forces and friction with other parts of the turbine engine, for example. This force or friction can lead to impairment of the part 1 which must be repaired to make the part 1 operational again.

[0048] Thus, as can be seen in FIG. 2, the part 1 comprises an unimpaired portion 5 and an at least partially impaired portion 6. The at least partially impaired portion 6 forms an area to be repaired. The at least partially impaired portion 6 extends, in the example of FIG. 2, from the upper panel 2 to a portion of the thickness of the core 4. According to another example not shown, the at least partially impaired portion 6 extends from the lower panel 3 to a part of the thickness of the core or from the upper panel 2 to the lower panel 3 thus passing through the entire thickness of the core 4.

[0049] The part 1 is repaired according to a repair method that will now be described on the basis of FIGS. 3a to 7.

[0050] As shown in FIGS. 3a and 3b, the repair method according to the invention comprises a first step (a) of removing at least one portion of the lower panel 3 or the upper panel 2 from the area to be repaired. The step (a) is for example carried out by machining the lower panel 3 or the upper panel 2. Thus, as best seen in the example in FIG. 3b, the core 4 is devoid of the upper panel 2 in the area to be repaired. The removal is achieved by removing at least one portion of each ply 2a. The removal of each ply 2a is done in an impaired manner, i.e., there is a removal R between each ply 2a.

[0051] In a second step (b) of the method, shown for example in FIG. 4, at least one portion of the core 4 is removed from the area to be repaired. The removal of the core 4 in step (b) is for example achieved by machining the honeycomb structure. Advantageously, the step (b) of removing at least one portion of the core 4 is carried out according to a profile according to the cross-section of the part in the form of an ellipse 7, the ellipse 7 having a small axis Y and a large axis X. The step (b) of removing the core 4 allows the initial size of a cell 4a to be known and to ensure the final verification of the repair.

[0052] At the end of steps (a) and (b) of the method, the part 1 has the area to be repaired free of the lower panel 3 or upper panel 2 and at least one portion of the core 4 and an unimpaired portion 5 surrounding the area to be repaired. The unimpaired portion 5 comprises the lower panel 3, the upper panel 2 and the core 4 between the lower panel 3 and the upper panel 2.

[0053] Then, according to a third step (c) of the method shown as an example in Figure the core 4 is reformed in the area to be repaired directly on the part 1 by additive manufacturing. The additive manufacturing method is, for example, a concentrated energy deposition method known by the acronym DED for “Direct Energy Deposition”, in particular when the core 4 is metallic. According to another example, the additive manufacturing method is a fused deposition modelling (FDM) method, in particular when the core 4 is polymeric.

[0054] Advantageously, the step (c) comprises a sub-step (c1) of providing a digital model comprising spatial coordinates of the unimpaired portion 5 of the core 4. The step (c) further comprises a substep (c2) of supplying a first repair material to an additive manufacturing device 8.

[0055] The additive manufacturing device 8 is for example shown in FIGS. 6a and 6b. It comprises a nozzle 8c and for example a motor 8a and a heating head 8b. The nozzle 8c is for example mounted on the heating head 8b. The nozzle 8c is for example cylindrical or conical.

[0056] According to a first example of embodiment shown in FIG. 6a, the ellipse 7 according to which the removal was carried out has a height measured along the minor axis Y greater than or equal to the radius of the nozzle 8c. Advantageously, the ellipse 7 has a width measured along the major axis X greater than or equal to twice the radius of the nozzle 8c.

[0057] According to a second example of embodiment shown in FIG. 6b in which the nozzle 8c is offset with respect to the motor 8a, the nozzle 8c has a diameter greater than or equal to twice the distance D separating the cells 4a.

[0058] Advantageously, the first repair material is identical to the material forming the core 4. This improves the bond strength between the core 4 of the unimpaired portion and the repaired core 4. Thus, the first repair material is for example made of a metallic material such as aluminium.

[0059] Next, a sub-step (c3) is performed in which the first repair material is deposited on the part 1 according to the spatial coordinates acquired in the step (c1) to reform the core 4. Thus, as shown in FIGS. 5a and 5b, the core 4 is restored.

[0060] The method according to the invention then comprises a step (d) of reforming the lower panel 3 or the upper panel 2 in the area to be repaired directly on the part 1. The step (d) advantageously comprises a sub-step (d1) of reforming a first ply 2a. The sub-step (d1) is repeated according to the number of plies 2a forming the lower panel 3 or upper panel 2. As the removal of the plies 2a during the step (a) was carried out in an impaired manner, the mechanical strength of the part 1 is improved.

[0061] FIG. 7 shows an example where the upper panel 2 is reformed.

[0062] In this way, the invention allows to restore the part 1 in its entirety without adding connecting parts that make the part 1 heavier and more complex. Also, the mechanical properties of the part 1 are preserved since the complete structure of the part 1 is restored.