Patent Application
20180127081
This application claims the benefit of and priority to European patent application No. 16382507.8, filed on Nov. 4, 2016, the entire disclosure of which is incorporated by reference herein.
The present disclosure refers in general to panel structures for the manufacture of an aircraft, in particular, for its fuselage and empennage section.
More in particular, it is an object of the present disclosure to provide a reinforced panel structure for an aircraft, which is capable of withstanding high energy impacts, such as a bird strike, a blade release, or an engine debris impact, with a minimized damage.
The disclosure herein also refers to a method for manufacturing such a panel structure.
The use of composite materials formed by an organic matrix and unidirectionally orientated fibers, such as Carbon Fiber Reinforced Plastic (CFRP), in the manufacture of structural components of an aircraft, for example fuselage skin panels, torsion boxes, stringers, ribs, spars etc., is well known in the aeronautical industry.
Typically, skin panels are stiffened by several stringers longitudinally arranged, in order to provide strength and guarantee a proper buckling behavior of the skin panels. The stringers are conventionally co-cured, co-bonded, secondarily bonded or bolted to the skin panel.
These reinforced panels must be designed to meet both aerodynamics and structural requirements, such as a bird collision or blade release.
As known, bird-plane collisions during flight, take-off and landing happens every day, jeopardizing people and aircraft integrity.
Also, in propeller aircrafts, blades may break, in part or completely, or be entirely released from a propeller hub. Usually, these releases lead to serious damages in the aircraft structure and/or its systems due to the impact, and to unbalanced situations for the engine due to the broken or released blade.
For that, airworthiness authorities have requested aircraft manufacturers to consider the impact scenario due to a bird or a blade collision, in order to guarantee that the aircraft is capable of maintaining flight long enough to reach a landing site.
Current solutions are mainly based on providing localized reinforcements at spots indicated by debris trajectory studies. No significant modifications of the structure of the aircraft are considered, as penetration in the structure is allowed.
However, this situation changes if propeller engines are installed far from the central fuselage section, as in the rear section of the fuselage, where skin panels may be thinner and the residual strength after a blade impact may be compromised.
It would therefore be desirable to provide technical ways that comply with airworthiness requirements to ensure a safe continuation of flight and landing of an aircraft that had suffered a collision.
The present disclosure overcomes the above-mentioned drawbacks by providing a panel structure for an aircraft, which minimizes the damage caused by an impact.
One aspect of the present disclosure refers to a panel structure for an aircraft that comprises at least one composite layer and at least one net-shaped layer attached to the at least one composite layer, wherein the net-shaped layer comprises a material suitable or configured to improve the impact resistance of the panel structure.
Thus, the disclosure herein provides a new panel structure designed, including a high-strength internal net/skeleton. Thus, instead of traditional monolithic panels (metallics or composites), the disclosure herein provides panels with improved impact resistance performance.
With this configuration, panels are designed to spread loads through a large area (the net-shaped layer) when a high energy impact is received. This way, the disclosure herein offers an impact reinforced panel.
Another aspect of the disclosure herein refers to an aircraft, comprising a fuselage, an empennage, a skin covering the fuselage and the empennage, and a panel structure as described, wherein at least part of the fuselage and/or empennage skin is formed by the panel structure.
Finally, another aspect of the disclosure herein refers to a method for manufacturing a panel structure for an aircraft, comprising providing at least one layer of composite material, providing at least one net-shaped layer comprising a material suitable or configured to improve the impact resistance of the at least one composite layer, and attaching the at least one net-shaped layer to the at least one composite layer to form an impact reinforced panel structure.
The method of the disclosure herein provides several alternatives for attaching the net-shaped layer to the composite layer.
The method of the disclosure herein provides a simple and cost-effective way of producing an impact reinforced skin panel.
For a better comprehension of the disclosure herein, the following example drawings are provided for illustrative and non-limiting purposes, wherein:
The panel structure 1 of
The net-shaped layer 2 of
Preferably, the net-shaped layer 2 comprises at least one of the following materials: steel, titanium, aluminium, carbon fiber, aramid fibers (Kevlar®), ultra high molecular polyethylene (Dyneema®), PBO (Zylon®).
With these materials, the net-shaped layer 2 provides an impact protection reinforcement that improves the damage tolerance capacity of a conventional panel skin of an aircraft. Thus, the panel of the disclosure herein increases the impact protection performance, and minimizes the damage area due to impacts.
The net-shaped layer 2 may have different configurations. Preferably, the net-shaped layer 2 has a polygonal configuration, such as a rhomboid configuration as shown in
In a preferred embodiment, the net-shaped layer 2 is set in knotted form, comprising a plurality of meshes 7 defined by corner knots 8 formed by at least two wires 9.
Also, as shown in
Thus, the net-shaped layer 2 acts as a barrier in case of a high energy impact, spreading the loads of the impact over the entire layer, and minimizing the damage contention.
As shown in
In the embodiment of
In the embodiment of
As shown in
The laminate sheet material 5 offers a smooth surface in order to fit the aerodynamic requirements of the panel structure 1. Also, the net-shaped layer 2 may be filled with a foam 6 or other light material to achieve an external smooth surface.
Finally,
According to the disclosure herein, the method for manufacturing a panel structure 1 for an aircraft comprises the steps of providing at least one layer of composite material 3, 4, providing at least one net-shaped layer 2, the net-shaped layer 2 comprising a material suitable or configured to improve the impact resistance of the at least one composite layer 3, 4, and attaching the net-shaped layer 2 to the at least one composite layer 3, 4 to form an impact reinforced panel structure 1.
Preferably, and as shown in
While at least one exemplary embodiment of the present inventioin(s) has been shown and described, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of the disclosure described herein. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, and the terms “a”, “an” or “one” do not exclude a plural number. Furthermore, characteristics or steps which have been described with reference to one of the above exemplary embodiments may also be used in combination with other characteristics or steps of other exemplary embodiments described above.
| Number | Date | Country | Kind |
|---|---|---|---|
| 16382507.8 | Nov 2016 | EP | regional |
