Method for manufacturing a shell element reinforced with support elements

Abstract

A method for manufacturing a shell element reinforced with support elements comprises providing a skin element that has an outer surface and an inner surface opposite the outer surface, providing a first support element that has an attaching side and a free side opposite the attaching side, attaching the first support element on the skin element such that the attaching side of the first support element faces the inner surface of the skin element. A first recess is introduced into the first support element that proceeds from the free side of the first support element and extends transversely to the first axis. A second support element is provided that has a support side and a front side opposite the support side. The second support element is inserted into the first recess of the first support element such that the support side faces the inner surface of the skin element.

Claims

1. A method for manufacturing a shell element reinforced with support elements, having the following steps of: (a) providing a skin element that has an outer surface and an inner surface disposed opposite the outer surface; (b) providing a first support element that extends along a first axis and has an attaching side that is parallel to the first axis, and a free side opposite the attaching side; (c) attaching the first support element on the skin element such that the attaching side of the first support element faces the inner surface of the skin element; (d) forming a first recess on the first support element, which proceeds from the free side of the first support element and extends transversely to the first axis; (e) providing a second support element that extends along a second axis and has a support side that is parallel to the second axis, and a front side opposite the support side; (f) inserting the second support element into the first recess of the first support element such that the support side faces the inner surface of the skin element, and such that the second axis of the second support element extends transversely to the first axis of the first support element; and (g) attaching the second support element on the first support element and/or on the skin element; wherein a projection is provided on the first support element, the projection extending on the free side away from the skin element; wherein the first recess is formed in the projection; and wherein the projection is formed by removing material from the first support element, on the free side thereof, on both sides of the first recess and at a distance from the first recess.

2. The method of claim 1, wherein a second recess is formed on the second support element, the recess extending from the support side of the second support element and transversely to the second axis, and wherein the second support element is inserted into the first recess of the first support element at the location of the second recess such that the first and second recesses intersect one another during the insertion, and the sections of the second support element located next to the second recess encompass the first support element.

3. The method of claim 2, wherein the first recess extends from the free side to a first end point that is spaced apart from the attaching side by a first distance, wherein the second recess extends from the support side to a second end point that is spaced apart from the front side by a second distance, and wherein the length of the first distance corresponds to the length of the second recess from the support side to the second end point.

4. The method of claim 1, wherein a first end point of the first recess lies in the plane in which the free side extends next to the projection.

5. The method of claim 1, further comprising attaching the first support element on the skin element by means of prepreg layers that are placed onto lateral surfaces of the first support element, between the attaching side and the free side, and onto regions of the inner surface of the skin element, next to the first support element, and which are subsequently cured.

6. The method of claim 1, further comprising attaching the second support element on the first support element by means of prepreg layers that are placed onto lateral surfaces of the first support element, between the attaching side and the free side, and onto lateral surfaces of the second support element, between the support side and the front side, and which are subsequently cured.

7. The method of claim 1, wherein the second support element is attached on the skin element by means of prepreg layers that are placed onto lateral surfaces of the second support element, between the support side and the front side, and onto regions of the inner surface of the skin element, next to the second support element, and which are subsequently cured.

8. The method of claim 1, wherein, after the second support element has been attached on the first support element and/or on the skin element, the projection is removed to a level at which the free side extends next to the projection.

9. The method of claim 1, further comprising providing, on the skin element, additional support elements that are parallel to the first and/or the second support element.

10. A method for manufacturing a shell element reinforced with support elements, having the following steps of: providing a skin element that has an outer surface and an inner surface disposed opposite the outer surface; providing a first support element that extends along a first axis and has an attaching side that is parallel to the first axis, and a free side opposite the attaching side; attaching the first support element on the skin element such that the attaching side of the first support element faces the inner surface of the skin element; forming a first recess on the first support element, which proceeds from the free side of the first support element and extends transversely to the first axis; providing a second support element that extends along a second axis and has a support side that is parallel to the second axis, and a front side opposite the support side; inserting the second support element into the first recess of the first support element such that the support side faces the inner surface of the skin element, and such that the second axis of the second support element extends transversely to the first axis of the first support element; and attaching the second support element on the first support element and/or on the skin element; wherein a projection is provided on the first support element, the projection extending on the free side away from the skin element; wherein the first recess is formed in the projection; and wherein, after the second support element has been attached on the first support element and/or on the skin element, the projection is removed to a level at which the free side extends next to the projection.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The various embodiments will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:

(2) FIG. 1 shows a cured skin element made of CFRP material for manufacturing a shell element reinforced with support elements, in accordance with an embodiment;

(3) FIG. 2 shows a first support element that is disposed on the skin element of FIG. 1 and extends parallel to a further support element in accordance with an embodiment;

(4) FIG. 3 shows the first support element of FIG. 2 attached on the skin element of FIG. 1 by means of prepreg layers in accordance with an embodiment;

(5) FIG. 4 shows the first support element of FIG. 3 provided with a projection and a first recess that is provided in the projection in accordance with an embodiment;

(6) FIG. 5 shows the first support element of FIG. 4, wherein a second support element is disposed in the first recess so as to extend transversely to the first support element in accordance with an embodiment;

(7) FIG. 6 shows the arrangement of the first support element and the second support element of FIG. 5, wherein the second support element is attached on the first support element and on the skin element by means of prepreg layers in accordance with an embodiment; and

(8) FIG. 7 shows the arrangement of the first support element and the second support element of FIG. 6, wherein the projection of the first support element, and the second support element on its front side are machined off to the level of the free side of the first support element in accordance with an embodiment.

DETAILED DESCRIPTION

(9) The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

(10) FIGS. 1 to 7 show various steps of an embodiment of the method for manufacturing a shell element 5, in particular an aircraft structural element, which is reinforced with support elements 1 and 3.

(11) According to the depicted embodiment of the method, the first step is to provide a skin element 7 made of CFRP material, namely an outer skin element of an aircraft structure, in this case that has an outer surface 9 and an inner surface 11 opposite the outer surface 9 (step (a), see FIG. 1).

(12) Subsequently, a first support element 1, for example a stringer element, is provided (step (b)), wherein the first support element extends longitudinally along a first axis 13 and has an attaching side 15, which extends parallel to the first axis 13, and a free side 17 opposite the attaching side 15, the first support element being disposed on the skin element 7 such that the attaching side 15 of the first support element 1 rests on the inner surface 11 of the skin element 7 (see FIG. 2).

(13) The next step is to attach the first support element 1 on the skin element 7 by means of prepreg layers 19 that are placed onto the lateral surfaces 21 of the first support element 1, between the attaching side 15 and the free side 17, and onto the regions 23 of the inner surface 11 of the skin element 7, next to the first support element 1, and are subsequently cured, wherein the attaching side 15 of the first support element 1 faces the inner surface 11 of the skin element 1 and rests thereon (step (c), see FIG. 3).

(14) Subsequent thereto, a first recess 25, in the form of a slot, is introduced into the first support element 1, wherein the first recess 25 extends away from the free side 17 of the first support element 1 and transversely to the first axis 13 (step (d), see FIG. 4). The first recess 25 extends away from the free side 17 to a first end point 27 that is spaced apart from the attaching side 15 by a first distance 29. In the next step, or in a preceding step, a projection 31 is provided on the first support element 1, the projection extending away from the skin element 7 on the free side 17. The first recess 25 is formed in projection 31. The projection 31 is formed by removing material from the first support element 1, on the free side 17 thereof, namely on both sides of the first recess 25 and at a distance from the first recess 25 (see FIG. 4). This material removal can be implemented, for example, by means of milling or also by means of grinding. The first end point 27 of the first recess 25 is located in the plane in which the free side 17 extends next to the projection 31.

(15) A second support element 3 is then provided, which can be a stringer element, for example, just as is the case with the first support element 1, and which extends longitudinally along a second axis 33 and has a support side 35 and a front side 37 opposite the support side 35 (step (e), FIG. 5). A second recess 39 is introduced into the second support element 3 in the form of a slot, which extends away from the support side 35 of the second support element 3 and transversely to the second axis 33.

(16) Next, the second support element 3 is inserted into the first recess 25 of the first support element 1 such that the support side 35 faces the inner surface 11 of the skin element 7 and rests thereon, and such that the second axis 33 of the second support element 3 extends transversely to the first axis 13 of the first support element 1 (step (f), see FIG. 5). The second support element 3 is thereby inserted into the first recess 25 of the first support element 1 at the location of the second recess 39 such that the first and second recesses 25 and 39 cross or intersect one another during the insertion, and the sections 41a and 41b of the second support element 3 located next to the second recess 39 grip the first support element 1. The second recess 39 in the second support element 3 extends away from the support side 35 to a second end point 43, which is spaced apart from the front side 37 by a second distance 45. The length of the first distance 29 corresponds to the length of the second recess 39 from the support side 35 to the second end point 43, thereby allowing the second support element 3 to rest, via the support side 35, on the inner surface 11 of the skin element 7 and support skin element (see FIG. 5). At the same time, the length of the second distance 45 corresponds to the length of the first recess 25 from the free side 17 to the first end point 27, so that the front side 37 of the second support element 3 is aligned with the free side 17 of the first support element 1 in the region of the projection 31.

(17) Finally, the second support element 3 is attached on the first support element 1 and on the skin element 7 (step (g), see FIG. 6). The second support element 3 is attached on the first support element 1 by means of prepreg layers 19 that are placed onto the lateral surfaces 21 of the first support element 1, between the attaching side 15 and the free side 17, and onto the lateral surfaces 47 of the second support element 3, between the support side 35 and the front side 37, and which are subsequently cured. The second support element 3 is likewise attached on the skin element 7 by means of prepreg layers 19 that are placed onto the lateral surfaces 47 of the second support element 3, between the support side 35 and the front side 37, and onto the inner surface 11 of the skin element 7 in the region 49 next to the second support element 3, and which are subsequently cured.

(18) As the final step, after the second support element 3 has been attached on the first support element 1 and on the skin element 7, the projection 31 is machined off, by means of milling or grinding, to the level in which the free side 17 extends next to the projection 31 (see FIG. 7). Likewise, the second support element 3 is machined off on the front side 37 to the level of the free side 17 such that the free side 17 and the front side 37 extend in one plane.

(19) Further support elements 51 are provided parallel to the first and second support elements 1 and 3 and are applied on the skin element 7 in the same manner as the first and second support elements 1 and 3. A shell element 5 that is made of CFRP material and is reinforced with support elements 1, 3, and 51 can be manufactured particularly easily and rapidly in this manner, wherein support elements 1 and 3 are provided that extend perpendicularly to one another, i.e., cross over one another without a structural weakening at the intersection point.

(20) While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the present disclosure as set forth in the appended claims and their legal equivalents.