Patent Application
20070056246
The present invention refers to a composite beam with a corrugated-shaped web.
A preferred application of the composite beam according to the invention is an aircraft fuselage.
The advantages of corrugations are largely known in the structures community, mainly on civil applications. For many years, metallic corrugated beams have been used to improve efficiency and to save weight. Trapezoidal corrugation in the webs enables thinner webs and/or avoids the need of stringers. Different studies (Masami Hamada—1994—, C. L. Chan & Y. A. Khalid —2002—) concluded that there is a web weight reduction around 10% by the use of a corrugation.
As far as such undulations applied to composite beams are concerned, one may encounter several issues. A proper design might try to provide continuity of the web's plies towards the flanges. In a corrugated web, this implies that the tape or fabric, near the flanges, has to follow the path of the corrugation in addition to the fold to be joined to the flange. All composite technologies have limitations for the minimum achievable radius. Therefore, unless the radii (and thus the corrugation) are large enough, loosing effectivity of the web, tight curvatures are not affordable.
Patent application US 2004/0040252 and Patent U.S. Pat. No. 6,520,706 disclose composite beams having sinusoidal-shaped webs in which additional parts are used to join the web to the flanges. This might increase by a fair amount the total cost of the beam as such additional parts' manufacturing and installation costs are not negligible.
The composite beam according to the invention comprises:
a web having a corrugated-shaped profile, with aligned parts in two parallel planes in the longitudinal direction and tilted parts between them;
two flanges;
a first element of C-shape and a second element of beam-shape, each of them having webs bonded to the parallel parts of the corrugated web in one plane enclosing the beam web between them, and having the caps of said first and second elements bonded to one or two additional single flanges or bonded between them to form the beam flanges.
This design solves the problem of joining a corrugated-shaped web to the flanges, avoiding manufacturing restrictions while folding the composite plies of the web towards the flanges.
One advantage of this invention is that the beam is cost-effective and able to save weight compared to straight-web beams.
Other features and advantages of the present invention will arise from the following detailed description of an illustrative embodiment of the object of the invention regarding the attached figures.
a and 5b shows a schematic plan view of two different corrugated-shaped webs.
In a first embodiment of this invention, the beam 41 has an I-shaped profile and comprises the following elements: a corrugated web 21, two flanges 7, 9 and two C-shaped elements 33, 43. In addition, for the manufacturing processes, other elements such as adhesive 26 qualified at temperature for the interface between the web 21 and the flanges 7, 9 (in a similar way to sandwich constructions) and filler could be required.
The web 21 has a corrugated-shaped profile having aligned parts 22, 23 in two parallel planes 25, 27 in the longitudinal direction and tilted parts 29 between them.
The C-shaped element 33 comprises web 35 and caps 37, 39. Similarly the C-shaped element 43 comprises web 45 and caps 47, 49. Both elements 33, 43 point outwards and are placed one at each side of the corrugated web 13 The web 35 of the C-shaped element 33 is bonded (co-cured, co-bonded or secondary bonded depending on the manufacturing process) to the aligned parts 23 of the web 21 in plane 27 and its caps 37, 39 are bonded (co-cured, co-bonded or secondary bonded depending on the manufacturing process) to the flanges 7, 9 to form the beam flanges 17, 19.
Similarly the web 45 of the C-shaped element 43 is bonded to the aligned parts 22 of the web 21 in plane 25 and its caps 47, 49 bonded to the flanges 7, 9 to form the beam flanges 17, 19.
This design solves the problem of joining the corrugated web 13 to the flanges 7, 9 in a composite beam in a cost-effective way. In addition, the corrugated web 21 aims to stabilize the whole web. A trapezoidal-shaped corrugation gives support to the webs 35, 45 of the C-shaped elements 33, 43, avoiding, thus, buckling issues and the need for additional stringers or a thicker web.
In principle this invention covers any possible angle that could feature tilted parts 29 with aligned parts 22 and 23 as shown in
On the other hand, the C-shaped elements function is twofold: to transfer the load from one flange to the other and to joint the web 21 with the flanges 7, 9.
As shown in
In a second embodiment of this invention, the beam 51 has a C-shaped profile and comprises the following elements: a corrugated web 21 and two C-shaped elements 33, 53.
The C-shaped element 33 comprises web 35 and caps 37, 39. Similarly the C-shaped element 53 comprises web 55 and caps 57, 59. Both elements 33, 53 are placed parallel one at each side of the corrugated web 21.
The webs 35, 55 of the two C-shaped element 33, 53 are bonded (co-cured, co-bonded or secondary bonded depending on the manufacturing process) to the aligned parts 23, 22 of the web 21 in planes 27, 25 and its caps 37, 57; 39, 59 are bonded (co-cured, co-bonded or secondary bonded depending on the manufacturing process) to form the beam flanges 17, 19.
In a third embodiment of this invention, the beam 61 has a J-shaped profile and comprises the following elements: a corrugated web 21, one flange 9, one C-shaped element 33 and one Z-shaped element 63.
The C-shaped element 33 comprises web 35 and caps 37, 39. Similarly the Z-shaped element 63 comprises web 65 and caps 67, 69. Both elements 33, 63 and are placed one at each side of the corrugated web 21.
The webs 35, 65 of elements 33, 63 are bonded (co-cured, co-bonded or secondary bonded depending on the manufacturing process) to the aligned parts 23, 22 of the web 21 in planes 27, 25. Its upper caps 37, 67 are bonded to form the upper beam flange 17. Its lower caps 39, 69 are bonded to flange 9 to form the lower beam flange 19.
Manufacturing methods to be applied could be pre-impregnated material laid by means of ATL equipment for the different elements with subsequent hot-forming, curing, co-bonding and/or secondary bonding steps, but also textiles laid up on moulds and infused with resin systems (liquid or film) prior to curing of elements and bonding processes.
Those modifications comprised within the scope defined by the following claims may be introduced in the preferred embodiment described above.
| Number | Date | Country | Kind |
|---|---|---|---|
| 5381044 | Sep 2005 | EP | regional |
