DE102008056702B4 - airplane window - Google Patents

Abstract

Aircraft window with a window frame (6), a seal (5) and a window pane (201), the window pane (201) being fastened to the window frame (6) via the seal (5), the window pane (201) having: a monolithic one Layer (202); wherein the monolithic layer (202) has an inside (204) and an outside (205); wherein the inside (204) and the outside (205) are each covered by a fiber-reinforced layer (203); wherein the fiber-reinforced layers (203) are attached to the monolithic layer (202) as outer cover layers, so that the fiber-reinforced layers (203) are connected flatly to the monolithic layer (202); wherein the window pane (201) is made in one piece.

Description

Field of the invention

The invention relates to aircraft windows with a monolithic layer and two fiber-reinforced layers. Furthermore, the invention relates to an aircraft with such an aircraft window.

Background of the invention

Known aircraft windows consist of an inner and an outer window pane. Both windows must be able to absorb the full differential pressure, the interior having to endure this load case only once, namely in the event that the outer window is destroyed. In this case, the inner window must ensure a safe onward flight to the landing. To ensure that the inner pane remains free of load during normal flight operation, the pane is provided with a small ventilation hole or the gasket has a ventilation channel, which ensures pressure equalization between the cabin and the space between the panes. The installation of the windows is done in such a way that no structural loads are transmitted into the window.

Polycarbonate or polymethyl methacrylate (PMMA) are used today as the material. Both materials are thermoplastics that solidify amorphously, are weatherproof, bendable, tensile and impact resistant. The use of polycarbonate is decreasing, as it tends to yellow during use.

EP 0846616 B1 . DE 198 06 108 A1 and EP 0936139 B1 each describe double-pane cabin windows for an aircraft.

The known "monolithic" type double pane solutions mentioned above require a large pane thickness in order to be able to remain within the requirements for maximum disk deflection in an aircraft. A limit to the maximum allowable deflection of the windows of the aircraft is necessary for reasons of aerodynamics. This necessary in the known double panes large disc thickness is associated with high wheel weight. In addition, a second disc is provided, which must ensure a safe flight to the next landing in case of failure of the first disc, as already mentioned above.

Out WO 2006/014961 A1 the use of transparent fiber reinforced disc material is known. The fiber-reinforced disc material consists of fibers and a matrix and is transparent. So far, however, no material combination fiber / matrix was found, which could achieve a significant increase in strength or stiffness, on the other hand remains transparent over the entire operating temperature range of an aircraft window. Both of the above conditions must be met for reasonable use as aircraft windows. The lack of transparency over the entire operating temperature range results from the very different thermo-optical properties (change in refractive indices over temperature) of fiber and matrix material. Based on a tolerance requirement for the difference between the refractive indices of fiber and matrix of +/- 0.002 for unrestricted transparency, only transparent fiber-reinforced materials can be achieved with a service temperature window of several 10 ° C temperature difference. However, the requirements for an aircraft window are 135 ° (-55 ° C to 80 ° C).

Double-pane cab windows, however, have relatively large pane thicknesses and a relatively high pane weight and, for safety reasons, require an embodiment with two monolithic panes.

The US 2006/00 63 880 A1 relates to a transparent panel composite with a transparent fiber-reinforced polymer glass layer for buildings, vehicles, aircraft and ships.

The US 2005/00 82 432 A1 describes a window assembly for cockpit and cabin windows of an aircraft with an outer glass window which is removably mounted by means of screws on a window construction and an aircraft skin.

From the DE 10 2006 025 930 A1 is a method for producing a fuselage structure of an aircraft or spacecraft known with inner and outer shells and with a torso forces receiving grid structure which is arranged between two window panes.

The US 35 25 658 A shows a transparent panel with a arranged between two glass layers fiber reinforced plastic.

Summary of the invention

It is the object of the invention to provide an aircraft window with improved rigidity and thus lower deflection compared to known disc solutions in a means of transport.

The object of the invention is solved by the subject matter of the independent claims, while advantageous developments of the invention are embodied by the dependent claims.

According to the invention, an aircraft window is provided with a window frame, a gasket and a window pane, the window pane being fastened to the window frame via the gasket. The windowpane has a monolithic

Layer, wherein the monolithic layer has an inside and an outside.

The inside and the outside are each covered by a fiber-reinforced layer.

According to the invention, the monolithic layer and the fiber-reinforced layers are sandwiched. The monolithic layer is covered on the inside and outside by a respective fiber-reinforced layer.

According to the invention, the monolithic layer has an inside and an outside, wherein the inside and the outside of each of a fiber reinforced layer is covered.

Such a window pane with fiber-reinforced layers as outer cover layers and a monolithic transparent core represent a type with which it is possible to make the best possible use of Steiner's share in the moment of area of the pane. As a result, the resistance to a deflection or the rigidity of the window pane is increased. According to Steiner's Theorem, the moment of inertia of a rigid body, and hence the resistance of the cross-sectional area to deflection, increases the moments of inertia of bodies connected to the rigid body, thereby increasing the total moment of inertia of the cross-section against deflection. The moments of inertia of the connected bodies enter into the total moment of inertia with the square of the distance to the neutral fiber.

Such a window pane has an increased rigidity compared to a purely monolithic pane. This increase in stiffness means that either the deflection of the window caused by the internal pressure of the cabin is reduced, which has a positive effect on the aerodynamics of, for example, an aircraft, or that the wall thickness of the pane can be reduced while the maximum wheel deflection remains constant. Alternatively, larger windows can be realized with the same deflection today known window. The increased rigidity windowpane according to the invention can consist of several monolithic layers and fiber-reinforced layers. The windowpane is constructed such that the two types of layers are superimposed. The layer structure can be chosen differently depending on the purpose.

Such a window pane leads to a reduction of the disc deflection with a constant slice thickness.

Such a window pane also leads to the reduction of the pane thickness with constant disc deflection combined with the reduction of the weight of the pane.

Such a window pane allows an enlargement of the pane surface with constant maximum pulley deflection and constant pane thickness.

Such a window pane has a damage-tolerant failure behavior, so that it would be possible to dispense with a second pane, which is known from the prior art.

According to a further embodiment of the invention, the monolithic visible light layer is made transparent. The monolithic layer may consist of different materials that are transparent to visible light.

Under visible light is basically understood light from a wavelength of about 380 nm to about 780 nm.

According to one embodiment of the invention, the fiber-reinforced layer is made transparent to visible light. In this case, the fiber-reinforced layer can be made of any material that ensures the transparency of visible light.

According to a further embodiment, the fiber-reinforced layer comprises reinforcing fibers and a transparent matrix.

According to another embodiment of the invention, the reinforcing fibers comprise glass fibers. The reinforcing fibers may also comprise any other suitable material having high reinforcing properties, such as silicone dioxide, graphite, or a polymer such as nylon or polycarbonate.

According to another embodiment of the invention, the transparent matrix is designed as a polymethyl methacrylate (PMMA) matrix. In this case, the matrix can likewise be formed from a transparent epoxy resin. The epoxy resin is selected based on transparency, tensile strength and refractive index.

In accordance with another embodiment of the invention, at least a portion of the reinforcing fibers of the fiber reinforced layer are formed with a diameter of such a size as to allow visible light to pass through the fiber reinforced layer.

Such a windowpane allows the reinforcing fibers to have a different refractive index than the transparent matrix, without the transparency of the fiber-reinforced layer becoming opaque. Further, the fiber strength increases as the diameter of the transparent reinforcing fiber decreases because surface defects are reduced.

According to a further embodiment, the reinforcing fibers of the fiber-reinforced layer are made with diameters smaller than 380 nm. 380 nm denotes the limit of visible light. Preferably, the reinforcing fibers have a diameter between about 10-380 nm. Thus, the reinforcing fibers have a diameter smaller than the smallest wavelength of visible light. Due to the small diameter of the fibers, the visible light can pass through these layers almost unhindered. Since in this case the fiber does not have to be transparent, there is no temperature dependence of the transparency.

According to a further embodiment of the invention, the thickness of the fiber-reinforced layer is implemented in the deci-micron range. The realizable thickness of such layers is limited, since the superimposition of the reinforcing fibers may result in areas of non-transparent material which extend from the dimensions into the wavelength range of visible light and thus may impair the transparency.

According to the invention, the fiber-reinforced layer is attached to the monolithic layer.

Such attachment can be done for example by gluing. The fiber reinforced layer may also be attached by thermal joining to the monolithic layer. The fiber-reinforced layer is placed on the monolithic layer and then both layers are heated until they thermally bond.

According to the invention, the window pane is made in one piece. Due to a damage tolerant failure behavior of the disc can be dispensed with a second disc.

The means of transport is an aircraft.

According to a further embodiment of the invention, an aircraft is specified with a window pane according to the invention. In such an aircraft, the thickness of the pane and thus the weight of the panes can thus be reduced with a constant pane deflection and with a constant size of the windows.

Further, there is provided a method of manufacturing a windowpane for a vehicle, the method comprising the steps of: providing a monolithic layer; Attaching a fiber reinforced layer to the monolithic layer.

The individual features of the various embodiments can of course also be combined with each other, which can also be partly beneficial effects set, which go beyond the sum of the individual effects, even if they are not expressly described.

Brief description of the drawings

Exemplary embodiments will be described below with reference to the following drawings.

1 shows a cross-sectional view of an aircraft window.

2a shows a cross-sectional view of a window pane according to an embodiment of the invention.

2 B shows a cross-sectional view of a window pane.

2c shows a cross-sectional view of a window pane.

2d shows a cross-sectional view of a window pane.

2e shows a perspective view of a fiber reinforced layer according to an embodiment of the invention.

3 shows a cross-sectional view of an aircraft window according to an embodiment of the invention.

4 shows a schematic side view of an aircraft with multiple windows according to an embodiment of the invention.

5 shows a flowchart of a method.

Detailed Description of Exemplary Embodiments

Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings.

The illustrations in the figures are schematic and not to scale. In the following figure descriptions, the same reference numerals are used for the same or similar elements.

1 shows a cross-sectional view of an aircraft window 1 with an outer disk 2 and an inner disk 3 that have a seal 5 on a window frame 6 of the aircraft are attached. The window frame 6 is on the aircraft's outer skin 7 appropriate. A ventilation hole 4 in the inner disc ensures that a pressure equalization between the disc space and the cabin interior takes place.

2a shows a cross-sectional view of a window pane according to the invention 201 with a monolithic layer 202 with an inside 204 and an outside 205 , On the inside 204 and the outside 205 the monolithic layer 202 is in each case a fiber-reinforced layer 203 appropriate. This sandwich construction with fiber-reinforced layers as outer cover layers and a monolithic transparent core is the invention.

The monolithic layer is covered on the inside and outside by a respective fiber-reinforced layer. It is conceivable that the respective fiber-reinforced layers on the respective outer sides may be covered by a monolithic layer. Any alternate arrangement of monolithic layers and fiber reinforced layers is also conceivable. However, such variants do not represent solutions according to the invention.

2 B shows a cross-sectional view of a window pane 201 with a fiber reinforced layer 203 , each of a monolithic layer 202 on the inside and outside of the fiber reinforced layer 203 is covered.

2c shows a cross-sectional view of a window pane 201 with three monolithic layers 202 and two fiber reinforced layers 203 , The monolithic layers 202 and the fiber reinforced layers 203 are arranged alternately one above the other.

2d shows a cross-sectional view of a window pane 201 with a monolithic layer 202 and a fiber reinforced layer 203 on one side of the monolithic layer 202 is arranged.

2e shows a fiber reinforced layer 203 with a transparent matrix 207 and a plurality of reinforcing fibers 206 , The reinforcing fibers 206 are in the matrix 207 integrated and have a diameter d. In one embodiment, the diameter d is the reinforcing fibers 206 less than the wavelength of visible light, for example, less than about 400 nm to 600 nm. The transparent reinforcing fibers 18 may have a diameter d between 10 nm to 400 nm. Due to the diameter d of the reinforcing fibers 206 which is smaller than the wavelength of visible light, is the light transmittance of the reinforcing fibers 206 very high.

In one embodiment of the invention, the reinforcing fibers 206 within the transparent matrix 207 distributed so that it is about 10-60% of the total volume of the fiber reinforced layer 203 turn off. Due to the high strength of the transparent reinforcing fibers 206 can increase the concentration of reinforcing fibers 206 that are in the transparent matrix 207 are integrated, reduce, for example, when the diameter d of the transparent reinforcing fibers 206 reduced without the structural properties with respect to tensile and compressive strength of the fiber-reinforced layer 203 be reduced.

The reinforcing fibers 206 can be within the transparent matrix 207 be arranged in any orientation, without the structural properties with respect to tensile and compressive strength of the fiber-reinforced layer 203 to reduce. Any arrangement of reinforcing fibers 206 within the transparent matrix 207 make a fiber reinforced layer 203 with almost isotropic material properties, for example, with approximately the same strength in all directions. Therefore, the fiber reinforced layer 203 be incorporated as a structural load bearing component in a means of transport.

3 shows a window pane according to the invention 201 in an airplane window 1 with a monolithic layer 202 and each with a fiber-reinforced layer 203 placed on the outside and the inside of the monolithic layer 202 are attached. The window glass 201 thus has a monolithic layer 202 and two fiber reinforced layers 203 on, which are attached to each other. The window glass 201 is about a seal 5 on a window frame 6 attached to the plane. The window frame 6 is on the aircraft's outer skin 7 appropriate.

4 shows a schematic side view of an aircraft 401 with several windows according to the invention 201 ,

5 shows a flowchart of a method for producing a window pane 201 for a means of transport. In a first step, a monolithic layer is provided 501 , The second step consists of attaching a fiber reinforced layer to the monolithic layer 503 , The attachment of the fiber-reinforced layer to the monolithic layer takes place for example by means of gluing. The attachment of the fiber-reinforced layer to the monolithic layer can also be effected by thermal joining. In thermal joining, the fiber-reinforced layer (s) and the monolithic layer (s) are superimposed. Subsequently, the layers are heated until the fiber-reinforced layer (s) and the monolithic layer (s) thermally bond. After a subsequent cooling phase is the window pane 201 completed.

Although the invention has been described with reference to exemplary embodiments, various changes and modifications can be made without departing from the scope of the invention. Such windows can also be used in areas other than aviation, such as trains, buses or ships, or any means of transport where a window pane is also needed or desired.

Reference signs in the claims are not to be considered as limiting.

LIST OF REFERENCE NUMBERS

1

airplane window

2

Outer disk

3

Inner disc

4

ventilation opening

5

poetry

6

window frame

7

Aircraft skin

201

windowpane

202

monolithic layer

203

fiber reinforced layer

204

inside

205

outside

206

reinforcing fiber

207

transparent matrix

401

aircraft

501

Providing a monolithic layer

502

Attaching a fiber reinforced layer to the monolithic layer

Claims (10)

Airplane window with a window frame ( 6 ), a seal ( 5 ) and a window pane ( 201 ), whereby the window pane ( 201 ) about the seal ( 5 ) on the window frame ( 6 ), the windowpane ( 201 ) comprising: a monolithic layer ( 202 ); the monolithic layer ( 202 ) an inside ( 204 ) and an outside ( 205 ) having; the inside ( 204 ) and the outside ( 205 ) each of a fiber-reinforced layer ( 203 ) are covered; wherein the fiber reinforced layers ( 203 ) as outer cover layers on the monolithic layer ( 202 ), so that the fiber reinforced layers ( 203 ) with the monolithic layer ( 202 ) are connected areally; the window pane ( 201 ) is made in one piece. Aircraft window ( 201 ) according to claim 1, wherein the monolithic layer ( 202 ) is transparent to visible light. Aircraft window ( 201 ) according to one of claims 1 or 2, wherein the fiber-reinforced layers ( 203 ) are made transparent to visible light. Aircraft window ( 201 ) according to one of claims 1 to 3, wherein the fiber-reinforced layers ( 203 ) Reinforcing fibers ( 206 ) and a transparent matrix ( 207 ) exhibit. Aircraft window ( 201 ) according to claim 4, wherein the reinforcing fibers ( 206 ) Comprise glass fibers. Aircraft window ( 201 ) according to claim 4 or 5, wherein the transparent matrix ( 207 ) as a polymethyl methacrylate matrix. Aircraft window ( 201 ) according to one of claims 1 to 6, wherein at least a part of the reinforcing chamfers ( 206 ) of the fiber-reinforced layers ( 203 ) having a diameter (d) of such a size as to allow visible light to pass through the fiber-reinforced layers ( 203 ). Aircraft window ( 201 ) according to one of claims 4 to 7, wherein the reinforcing fibers ( 206 ) of the fiber-reinforced layers ( 203 ) having diameters (d) smaller than 380 nm. Aircraft window ( 201 ) according to one of claims 1 to 8, wherein the thickness of the fiber-reinforced layers ( 203 ) in the deci-micrometer range. Aircraft ( 401 ) with an aircraft window according to one of claims 1 to 9.

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