Manufacturing method of a frame member of a door frame structure of an aircraft, the frame member, and the door frame structure

Abstract

The present invention describes a method for manufacturing a frame member (1) for a door frame structure (100) for an aircraft. Here, connection regions (21; 22) are produced on the assembly surfaces (20a; 20b) by generating surface structures on a first assembly surface (20a) and a second assembly surface (20b) of a connection member (20), wherein the connection member (20) is formed of a metallic material. The assembly surfaces (20a; 20b) of the connection member (20) are placed against a door frame member (10) and an attachment member (30), wherein the door frame member (10) and the attachment member (30) are each made of a fiber-reinforced thermoplastic material. In addition, the connection member (20) is welded to the door frame member (10) and the connection member (20) is welded to the attachment member (30). The frame member (1) and the door frame structure (100) are also described.

Description

Technical Field

[0001] The present invention relates to a manufacturing method of a frame member of a door frame structure of an aircraft, a frame member, and a door frame structure. Background Art

[0002] In the fuselage of an aircraft, doors are usually provided for passengers and on-board crew, as well as for loading and unloading the aircraft. Here, the doors are installed in a frame that is connected to the fuselage structure or forms part of the fuselage structure. In the closed state of the door, the door is locked and / or supported on the frame. During flight, the pressure inside the fuselage is usually significantly higher than the ambient pressure. The forces acting on the door due to the pressure difference must be accommodated by the frame.

[0003] Conventional frame configurations each have two mutually opposite members in each case, which are fastened to ribs or other structural components of the fuselage structure by attachment struts. In this case, for weight reasons, the members and attachment struts can be formed of fiber composite materials. Usually, in each case, metal angles are provided to fasten the attachment struts to the members and the fuselage structure, and the metal angles are screwed or riveted to the attachment struts and the members or the fuselage structure. To reduce weight and simplify the assembly of the frame, US2009 / 0146008A1 describes a frame having members made of titanium, where the attachment struts are formed integrally with or integrally formed on the members. Summary of the Invention

[0004] The object of the present invention is to provide a frame concept for a door of an aircraft, which is improved especially in terms of weight and assemblability.

[0005] For this purpose, the present invention proposes a method for manufacturing a frame member of a door frame structure of an aircraft, the frame member defining a door opening, the method having the following steps:

[0006] Forming a first connection area on a first assembly surface by generating a surface configuration of the first assembly surface of a connection member, wherein the connection member is formed of a metallic material;

[0007] Forming a second connection area on a second assembly surface by generating a surface configuration of the second assembly surface of the connection member, wherein the second assembly surface extends transversely with respect to the first assembly surface;

[0008] Placing the first assembly surface of the connection member against a door frame member made of a fiber-reinforced thermoplastic material;

[0009] Welding the connection member and the door frame member, wherein the thermoplastic material of the door frame member enters the first connection area of the connection member;

[0010] Place an attachment member against a second mating surface of the connecting member, wherein the attachment member is formed of a fiber-reinforced thermoplastic material; and

[0011] Weld the connecting member and the attachment member together on opposite sides of the connecting member that weld the door frame member and the connecting member together, wherein the thermoplastic material of the attachment member enters a second connection area of the connecting member.

[0012] The present invention also provides a door frame structure for an aircraft, having:[[]]END]]

[0013] A first frame member, the first frame member being the frame member according to the present invention;

[0014] A second frame member, the second frame member being the frame member according to the present invention;

[0015] A first transverse strut extending between the door frame members of the first frame member and the door frame members of the second frame member and fastened respectively at opposite ends of the first transverse strut to a first end portion of the door frame member of the first frame member and a first end portion of the door frame member of the second frame member; and

[0016] A second transverse strut extending between the door frame members of the first frame member and the door frame members of the second frame member and fastened respectively at opposite ends of the second transverse strut to a second end portion of the door frame member of the first frame member and a second end portion of the door frame member of the second frame member.

[0017] According to a first aspect of the present invention, there is provided a method for manufacturing a frame member for a door frame structure for an aircraft. According to the method, a first connection area is formed on an assembly surface of a connecting member by creating a surface texture of the first assembly surface of the connecting member (i.e., by roughening the assembly surface), wherein the connecting member is formed of a metallic material. For example, the connecting member can be an angle member in the form of an L-shaped or T-shaped member having a first web and at least one second web extending transversely with respect to the first web. Thus, in this step, a surface topography with protrusions and depressions is created on one surface of the connecting member. Due to the roughening, incisions or cavities are formed in the assembly surface. The thickness of the connection area can be particularly defined by the maximum height difference measured between the bottom of the cavity and the protrusions defining the cavity.

[0018] Furthermore, a second connection region is formed on the second mounting surface by generating a surface configuration of the second mounting surface of the connecting member, wherein the second mounting surface extends transversely with respect to the first mounting surface. This step is similar to the formation of the first connection region. For example, the first mounting surface may be located on the first web of the angle member, while the second mounting surface may be located on the second web of the angle member. Generally, the second mounting surface extends transversely with respect to the first mounting surface.

[0019] In a further step, the first mounting surface of the connecting member is placed against the door frame member. The door frame member is formed of a fiber-reinforced thermoplastic material. Generally, the door frame member is formed of a fiber composite material having a plurality of reinforcing fibers, particularly reinforcing fibers in the form of filaments or filament pieces, such as carbon fibers, glass fibers, ceramic fibers, aramid fibers, boron fibers, mineral fibers, natural fibers or plastic fibers or mixtures thereof, wherein the reinforcing fibers are embedded in a thermoplastic resin or matrix material. The door frame member can in particular be arranged to form a lateral boundary of a door opening of the airframe structure of an aircraft in the door frame structure of the aircraft. In this step, the connecting member is placed in contact with the door frame member. This is achieved by a certain contact pressure of the connecting member and the door frame member on one another. As described by way of example above, if the connecting member is formed as an angle member, the first web of the angle member is placed against the door frame member such that the first mounting surface makes surface contact, preferably direct surface contact, with the surface of the door frame member, that is to say without an optional intermediate layer. Thus, the second web protrudes from the door frame member.

[0020] Furthermore, the connecting member and the door frame member are welded together, wherein the thermoplastic material of the door frame member enters the first connection region of the connecting member. In this step, the thermoplastic material becomes plastically deformable in the region of the surface against which the first mounting surface of the connecting member abuts. In this molten state, the thermoplastic matrix material of the door frame member enters the cavities formed in the first mounting surface and solidifies there. Thus, the connecting member is fastened to the door frame member.

[0021] In a further step, the attachment member is placed against the second mounting surface of the connecting member, wherein the attachment member is formed of a fiber-reinforced thermoplastic material. In particular, the attachment member can be formed of the same fiber-reinforced thermoplastic material as the door frame member. The attachment member can in particular be arranged as a component for mechanically coupling the door frame member to the airframe structure of the aircraft, for example to a rib. The attachment member, which can also be referred to as an intercostal element, is placed against the second mounting surface of the connecting member by means of one surface, preferably placed in direct contact with this mounting surface, that is to say without an optional intermediate element. This placement step is carried out by a certain contact pressure of the connecting member and the attachment member on one another.

[0022] Finally, the connecting part and the attachment member are welded, wherein the thermoplastic material of the attachment member enters the second connection area of the connecting part. The welding of the connecting part and the attachment member is carried out similarly to the welding of the door frame member and the connecting part.

[0023] The steps of the method according to the invention can also be carried out in an order different from the above order. In particular, the formation of the first connection area and the second connection area on the first assembly surface and the second assembly surface of the connecting part can be carried out first. In addition, the formation of the first connection area and the second connection area on the first assembly surface and the second assembly surface of the connecting part can be carried out simultaneously.

[0024] The welding of the attachment member and the door frame member, each formed of fiber-reinforced thermoplastic material, to the connecting part formed of metal improves the automation ability of the assembly process. In addition, in this way, the number of mechanical connecting devices such as screws, bolts or rivets required for assembling the frame structure of the door of the aircraft can be reduced. This can reduce the weight and at the same time shorten the assembly time. Since the welding of the assembly surfaces of the connecting part to the attachment member and the door frame member results in surface connection of these parts, a more uniform mechanical stress distribution is achieved relative to rivet or screw connection. Therefore, stress concentration can be reduced. In addition, the welded connection has an advantage in terms of fatigue strength.

[0025] In one embodiment of the method, the formation of the first connection area and the second connection area of the connecting part is carried out respectively by melting the metal material on the first assembly surface and the second assembly surface by means of a laser beam, or by electrochemically roughening the first assembly surface and the second assembly surface respectively. Therefore, it can be provided that the assembly surface of the connecting part is roughened by melting the assembly surface of the connecting part within a specific thickness range by means of a laser beam. During the subsequent re-solidification of the metal material, the surface structure or surface topography of the connection area is formed. As described below, the advantage of performing such laser treatment is that the laser device for generating the laser beam required for this purpose can also be used to weld the connecting part to the door frame member and the attachment member. As an alternative to the laser treatment, electrochemical treatment of the assembly surface can also be carried out. Here, for example, an electrolyte material can be applied to the assembly surface, and material can be removed anodically from the corresponding assembly surface, that is, the assembly surface forms the anode of an electrochemical cell.

[0026] In a further embodiment, it is provided that the welding of the connecting part to the door frame member and the attachment member is in each case carried out by laser welding, ultrasonic welding or induction welding. In the case of all the above-mentioned welding methods, energy is introduced into the thermoplastic matrix material of the door frame member and the attachment member, thus melting the material. In the case of laser welding, this is carried out by means of a laser beam guided from the side of the connecting part or the corresponding other connecting object (i.e., the door frame member or the attachment member) to the contact area between the assembly surface of the connecting part and the connecting object. The advantage offered by laser welding is that the equipment costs of the process can be kept low overall, since the same laser device can be used for welding and for forming the connecting area of the connecting part. In addition, laser welding is advantageous in areas that are difficult to access spatially (for example, in the case of angled connecting parts). The introduction of energy into the thermoplastic material can also be achieved by ultrasonic welding, in which a sonotrode introduces vibrations into the connecting object and the thermoplastic material melts due to friction. In the case of induction welding, a metal mesh provided between the corresponding connecting object and the assembly surface of the connecting part is heated by voltage, thus melting the thermoplastic material.

[0027] In a further embodiment of the method, the first and second connecting areas of the connecting part are each formed with a surface topography having a height difference between 1 μm and 8 μm. Accordingly, the thickness of the connecting area is between 1 μm and 8 μm. In particular, due to the roughening, incisions or cavities with a depth between 1 μm and 8 μm are formed on the surface. The depth of the cavities limits the maximum depth of penetration of the thermoplastic material into the corresponding assembly surface. The depth can optionally be between 2 μm and 6 μm, preferably between 3 μm and 5 μm. In particular, within the latter range, a high mechanical strength of the welded joint between the connecting part and the door frame member or the attachment member is advantageously achieved.

[0028] In a further embodiment, in the method, a third connecting area is additionally formed on the third assembly surface by generating a surface configuration of the third assembly surface of the connecting part, wherein the third assembly surface is arranged opposite to and oriented towards the second assembly surface such that the second and third assembly surfaces form a receiving space. In this embodiment, the connecting part has an additional connecting surface. For example, for this purpose, the connecting part can have an additional third web that extends parallel to the second web and has a third assembly surface on the side facing the second web. The second web has a second assembly surface on the side facing the third web. The third connecting area on the third assembly surface can be formed using one of the above-mentioned methods and has the same thickness as the first or second connecting area.

[0029] In this embodiment, while placing the attachment member against the second mating surface of the connecting member, the attachment member is placed against the third mating surface of the connecting member by sliding the attachment member into the receiving space. Thus, here, the attachment member slides between the second web and the third web of the connecting member. In this case, the second mating surface and the third mating surface can be specifically arranged to have an interval that achieves a press fit relative to the attachment member. This provides the advantage that the contact pressure required for welding is generated between the attachment member and the connecting member without the need for additional clamping devices or the like.

[0030] Subsequently, the connecting member and the attachment member are welded at the second mating surface and the third mating surface of the connecting member, wherein, as already described, the thermoplastic material of the attachment member enters the second connecting region and the third connecting region of the connecting member.

[0031] According to a further embodiment, the first mating surface of the connecting member is placed against the joint region of the surface of the door frame member, and the second mating surface of the connecting member is placed against the joint region of the surface of the attachment member, wherein the door frame member and the attachment member are made of thermoplastic material in a thickness range between 1 μm and 8 μm from the surface in the joint region. Thus, in the attachment member and the door frame member, in each case, at least in the surface region, there are no reinforcing fibers in a specific cross-sectional region below the surface. In this embodiment, the connecting member with the corresponding mating surface is provided in such a region. Since in the joint region, the reinforcing fibers are arranged at a predetermined interval from the surface, specifically in the range between 1 μm and 8 μm, the misalignment of the fibers during welding is reliably prevented. In addition, a material reserve is provided that can be used to access the corresponding connecting regions of the connecting member. The thickness range of each of the attachment member or the door frame member made of thermoplastic material can especially also be between 2 μm and 6 μm, preferably between 3 μm and 5 μm.

[0032] In a further embodiment of the method, it is provided that the door frame member has a U-shaped cross-section formed by a transverse web and two side webs, and wherein the first mating surface of the connecting member is placed against the inner surface of the longitudinal web of the door frame member that extends between the side webs. Regardless of this embodiment, the door frame member is formed as an elongated member, for example having a linear, arcuate or substantially curved longitudinal extent. In this embodiment, the member has a U-shaped or C-shaped cross-section. Here, the cross-section is formed by a transverse web, and at each of the opposite ends of the transverse web, a side web is provided, and each of the side webs extends transversely with respect to the transverse web. The inner surface of the door frame member extends between the transverse webs, and the first mating surface of the connecting member is placed against this inner surface.

[0033] Here, it can optionally be provided that the connecting part is placed such that the first mounting surface abuts against the inner surface of the longitudinal web of the door frame member, so that the second mounting surface of the connecting part extends transversely with respect to the side web of the door frame member. If the connecting part is formed as an angle piece, then the connecting part is arranged on the inner surface of the longitudinal web such that the second web of the connecting part and, optionally, a third web of the connecting part, each extend between the side webs of the door frame member.

[0034] In a further embodiment of the method, it can be provided that the fibre-reinforced thermoplastic material of the door frame member and / or the attachment member contains polyetheretherketone (abbreviated as PEEK), polyphenylene sulphide (abbreviated as PPS), polyetherimide (abbreviated as PEI) or a similar thermoplastic material as the matrix material.

[0035] According to a further embodiment, titanium, a titanium alloy, aluminium, an aluminium alloy or a similar metallic material is used as the metallic material of the connecting part.

[0036] According to a further aspect of the invention, there is provided a frame part for a door frame structure of an aircraft. The frame part according to the invention has a door frame member made of a fibre-reinforced thermoplastic material, a connecting part made of a metallic material welded to the inner surface of the door frame member, and an attachment member made of a fibre-reinforced thermoplastic material welded to the connecting part.

[0037] According to this aspect of the invention, there is provided a frame part which can in particular be manufactured by the above method. Thus, the technical relationships and advantages discussed on the basis of this method also apply analogously to the frame part according to the invention, and vice versa.

[0038] The door frame member is formed as an elongate part, for example having a linear, arcuate or substantially curved longitudinal extent. The door frame member can in particular be arranged to form the lateral boundary of a door opening in the fuselage of the aircraft in a door frame structure of the aircraft. Here, for example, a door can be mounted on the door frame member. In addition, a stop element can also be provided on the door frame member, against which the door is supported in the closed state.

[0039] The attachment member, which can also be referred to as an intercostal element, is likewise formed as an elongate part, which preferably has a linear longitudinal extent. The attachment member can in particular be arranged to mechanically couple the door frame member to a part of the fuselage structure of the aircraft, for example to a rib or a further part of the frame part. The frame part preferably has a plurality of attachment members spaced apart from one another, each attachment member being welded to a further connecting part and via this further connecting part being welded to the door frame member.

[0040] In particular, the door frame member and the attachment member are mechanically connected by a connecting member made of metal, wherein the thermoplastic matrix materials of the door frame member and the attachment member enter the connection area of the assembly surface in the area of the surface against which the respective assembly surfaces of the connecting member abut. Due to this welded connection, the number of mechanical connection means such as screws, bolts or rivets required for assembling the door frame structure of the aircraft door is reduced. This can reduce the weight while shortening the assembly time. In addition, a more uniform mechanical stress distribution is achieved relative to rivet or screw connections. Therefore, stress concentration can be reduced. In addition, the welded connection has advantages in terms of fatigue strength.

[0041] According to an embodiment of the frame member, the connecting member is formed as an L-shaped or T-shaped angle member, wherein the connecting member is fastened to the door frame member by means of a first assembly surface and to the attachment member by means of a second assembly surface. Thus, the connecting member has a first web and at least one second web. Optionally, a third web may additionally be provided. The first web has a first assembly surface. The second web is attached to the rear surface of the first web opposite the first assembly surface and extends transversely with respect to the first web. In addition, the second web has a second assembly surface. A third assembly surface is provided on the optional third web, wherein the third assembly surface is arranged opposite the second assembly surface and is oriented to face the second assembly surface such that the second assembly surface and the third assembly surface form a receiving space. Here, the third web extends parallel to the second web, and the third assembly surface is provided on the side facing the second web. The second web has a second assembly surface on the side facing the third web. If the second web and the optional third web are each arranged close to the edge of the first web, the result is that the connecting member has an L-shaped cross-section. If the second web and the optional third web are each arranged in the central region of the first web, the result is that the connecting member has a T-shaped cross-section.

[0042] In a further embodiment of the frame member, the door frame member has a U-shaped or C-shaped cross-section formed by a transverse web and two side webs, and wherein the connecting member is fastened to the inner surface of the transverse web of the frame member extending between the side webs. Thus, the cross-section of the door frame member is formed by the transverse web, and one side web is provided at each of the opposite end portions of the transverse web, and the side webs each extend transversely with respect to the transverse web. The inner surface of the door frame member extends between the transverse webs, and the connecting member is welded to this inner surface by means of a first assembly surface.

[0043] In a further embodiment, the frame part additionally has a structural member made of a fiber-reinforced thermoplastic material and a further connecting part made of a metallic material. The further connecting part is welded to the inner surface of the structural member and to the end part of the attachment member which is located opposite the door frame member. The structural member is in particular formed as an elongate part, for example having a linear, arcuate or substantially curved longitudinal extent. For example, the structural member can be formed as a rib section of a fuselage structure. The attachment member thus extends between the door frame member and the structural member and is welded at its end parts to connecting elements which are in turn welded to the door frame member or to the structural member. The further connecting elements can be designed in the same way as the first connecting part which is welded to the door frame member. The structural member increases the mechanical stability of the frame part.

[0044] In a further embodiment, the frame part additionally has a door stop or a stop element. It is arranged on the outer surface of the door frame member which is opposite the inner surface and has a engagement projection which projects from the outer surface. The stop element can in particular be formed as a metallic element which is screwed onto the door frame member. Optionally, the door stop is arranged relative to the longitudinal extent of the door frame member such that it at least partially, preferably completely, overlaps the first mounting surface of the connecting part. In this way, it is possible to provide screws for fastening the door stop such that they extend through the door frame member and the connecting part with their shanks. In this way, metallic engagement surfaces are advantageously provided for the screw heads and the nuts respectively.

[0045] According to a further aspect of the invention, a door frame structure of an aircraft is provided. The door frame structure has a first frame part according to one of the above-described embodiments and a second frame part according to one of the above-described embodiments. Furthermore, the door frame structure has a first transverse strut which extends between the door frame members of the first frame part and the door frame members of the second frame part and is fastened to the first end part of the door frame member of the first frame part and to the first end part of the door frame member of the second frame part respectively. Furthermore, the door frame structure has a second transverse strut which extends between the door frame members of the first frame part and the door frame members of the second frame member and is fastened to the second end part of the door frame member of the first frame part and to the second end part of the door frame member of the second frame part respectively.

[0046] The door frame structure thus adjoins a door opening, in which a door can be pivotally mounted on one of the door frame members of the frame part.

[0047] Here, "fiber-reinforced thermoplastic material" should generally be understood to refer to a material that has various reinforcing fibers, particularly reinforcing fibers in the form of filaments or filament segments, such as carbon fibers, glass fibers, ceramic fibers, aramid fibers, boron fibers, mineral fibers, natural fibers, or plastic fibers, or mixtures thereof, where the reinforcing fibers are embedded in a thermoplastic resin or matrix material, such as polyetheretherketone (abbreviated as PEEK), polyphenylene sulfide (abbreviated as PPS), polyethyleneimine (abbreviated as PEI), or similar thermoplastic materials.

[0048] Regarding directional indications and axes, particularly those related to the profile of a physical structure, an axis, direction, or the profile of a structure "along" another axis, direction, or the axis, direction, or profile of a structure should be understood to mean that they, particularly the tangents generated at the corresponding points of the structure, extend at an angle relative to each other that is less than or equal to 45°, preferably at an angle less than 30° relative to each other, and particularly preferably extend parallel to each other.

[0049] Regarding directional indications and axes, particularly those related to the profile of a physical structure, an axis, direction, or the profile of a structure "transverse" to another axis, direction, or structure should be understood to mean that they, particularly the tangents generated at the corresponding points of the structure, extend at an angle relative to each other that is greater than or equal to 45°, preferably at an angle greater than or equal to 60° relative to each other, and particularly preferably extend perpendicular to each other. Brief Description of the Drawings

[0050] The present invention will be discussed below with reference to the accompanying drawings. In the figures:

[0051] Figure 1 A schematic diagram of the door frame structure of an aircraft according to an exemplary embodiment of the present invention is shown in a plan view;

[0052] Figure 2 A perspective view of a frame member for a door frame structure of an aircraft according to an exemplary embodiment of the present invention is shown;

[0053] Figure 3 Shows Figure 2 A cross-sectional perspective view of the door frame member of the frame member shown in;

[0054] Figure 4 A cross-sectional perspective view of a frame member according to another exemplary embodiment of the present invention is shown;

[0055] Figure 5 A schematic cross-sectional view of a connecting member of a frame member according to an exemplary embodiment of the present invention is shown;

[0056] Figure 6Shows a schematic diagram of forming a second connection area on a connection component, which is carried out as a step of the method according to an exemplary embodiment of the present invention;

[0057] Figure 7 Shows the Figure 6 detailed view of the area represented by the letter character X in;

[0058] Figure 8 Shows a schematic diagram of welding a connection component and an attachment member, which is carried out as a step of the method according to an exemplary embodiment of the present invention;

[0059] Figure 9 Shows a detailed view of the welded joint between a connection component made of a metallic material and a door frame member or an attachment member made of a fiber-reinforced thermoplastic material; and

[0060] Figure 10 Shows the Figure 9 detailed view of the area represented by the letter character Y in.

[0061] List of reference numerals

[0062] 1 - Frame member; 10 - Door frame member; 10a - Inner surface of the door frame member; 10b - Outer surface of the door frame member; 10A - First end portion of the door frame member; 10B - Second end portion of the door frame member; 11 - Transverse web of the door frame member; 11a - Inner surface of the transverse web; 12 - First side web of the door frame member; 13 - Second side web of the door frame member; 15 - Joint area; 20, 50 - Connecting member; 20a - First assembly surface of the connecting member; 20b - Second assembly surface of the connecting member; 20c - Third assembly surface of the connecting member; 21 - First connection area; 22 - Second connection area; 23 - Third connection area; 21P - 23P - Protrusion; 21V - 23V - Cavity; 24 - Receiving space; 25 - First web of the connecting member; 25b - Rear surface of the first web; 26 - Second web of the connecting member; 27 - Third web of the connecting member; 28 - Lateral end area of the first web; 30 - Attachment member; 30a - First surface of the attachment member; 30A - First end portion of the attachment member; 30B - Second end portion of the attachment member; 30b - Second surface of the attachment member; 31 - Transverse web of the attachment member; 32 - First side web of the attachment member; 33 - Second side web of the attachment member; 35 - Joint area of the attachment member; 40 - Structural member; 40a - Inner surface of the structural member; 41 - Longitudinal web of the structural member; 42 - First side web of the structural member; 43 - Second side web of the structural member; 60 - Door stopper; 62 - Joint protrusion; 100 - Door frame structure; 101 - First frame member; 101A - First end area of the first frame member; 101B - Second end area of the first frame member; 102 - Second frame member; 102A - First end area of the second frame member; 102B - Second end area of the second frame member; 103 - First transverse strut; 104 - Second transverse strut; 105 - Door opening; 200 - Laser source; 201 - Optical waveguide; 202 - Optical device; 300 - Welding automation device; 301 - Chassis; 302 - Manipulator; 303 - Moving arm; B - Laser beam; L - Longitudinal direction; M - Matrix material; F - Reinforcing fiber; X, Y - Area; d15 - Thickness range of the door frame member; d35 - Thickness range of the attachment member; d21 - d23 - Height differences of the first connection area, the second connection area, and the third connection area respectively.

[0063] In the drawings, unless otherwise specified, the same reference numerals are used to denote the same components or components with the same functions. Detailed Description

[0064] Figure 1The door frame structure 100 of an aircraft is shown by way of example. The door frame structure 100 has a first frame member 1,101, a second frame member 1,102, a first transverse strut 103, and a second transverse strut 104. The first frame member 101 and the second frame member 102 are arranged spaced apart from each other. The transverse struts 103, 104 extend transversely relative to the frame members 101, 102, or extend therebetween. The first transverse strut 103 is fastened to a first end region 101A of the first frame member 101 and a first end region 102A of the second frame member 102. The second transverse strut 104 is fastened to a second end region 101B of the first frame member 101 and a second end region 102B of the second frame member 102, wherein the second end regions 101B, 102B are opposite the first end regions 101A, 102A relative to the longitudinal extent L of the frame members. As Figure 1 schematically shown, the frame members 101, 102 and the transverse struts 103, 104 together define or delimit a door opening 105, which door opening 105 can be closed by a door (not shown).

[0065] Figure 2 is shown Figure 1 a perspective view of one of the frame members 1 schematically shown in. Figure 3 is shown Figure 2 a sectional perspective view of a door frame member 10 of the frame member 1 shown in, Figure 4 shows a further perspective view of the door frame member 10.

[0066] As Figures 2 to 4 shown, the frame member 1 has a door frame member 10, a connecting member 20, an attachment member 30, an optional structural member 50, and an optional further connecting member 40. In addition, the frame member 1 has one or more door stops or stop elements 60. In the Figure 1 and Figure 2 case of the frame member 1 shown by way of example, a total of seven attachment members 30 are provided.

[0067] As Figure 2 shown by way of example, the door frame member 10 is formed as an elongate member, which elongate member can in particular have an arcuate or substantially curved longitudinal extent. The door frame member 10 can in particular be designed as a profile member. In Figures 2 to 4The door frame member 10 shown by way of example has a U-shaped or C-shaped cross-section. Here, the cross-section is formed by a transverse web 11, a first side web 12, and a second side web 13. The side webs 12, 13 extend along each other in this case, in particular parallel to each other, and are connected by the transverse web 11. The door frame member 10 is formed of a fiber-reinforced thermoplastic material, for example, the thermoplastic material contains polyetheretherketone (abbreviated as PEEK), polyphenylene sulfide (abbreviated as PPS), polyethyleneimine (abbreviated as PEI), or a similar thermoplastic material as the matrix material M. Reinforcing fibers F, such as carbon fibers, glass fibers, ceramic fibers, aramid fibers, boron fibers, mineral fibers, natural fibers, or plastic fibers, or a mixture thereof, are embedded in the matrix material M.

[0068] Figure 5 A cross-sectional view of the connecting members 20, 50 is shown by way of example. The connecting member 20 generally has a first mounting surface 20a, a second mounting surface 20b, and an optional third mounting surface 20c. Generally, the second mounting surface 20a extends transversely with respect to the first mounting surface 20b, whereby a corner or an angle is formed by the mounting surfaces 20a, 20b.

[0069] Figure 5 The connecting member 20 shown by way of example is formed as a T-shaped angle member. The connecting member 20 has a first web 25, a second web 26, and an optional third web 27. The second web 26 and the third web 27 extend transversely with respect to the first web 25, and are arranged spaced apart from each other in the central region of the first web 25, and are connected to the first web. The first mounting surface 20a is located on the first web. The second web 26 and the third web 27 are provided on the rear surface 25b opposite to the first mounting surface 20a and project from the rear surface. The second web 26 has the second mounting surface 20b, and the optional third web 27 has the third mounting surface 20c. It can be seen that the second mounting surface 20b and the third mounting surface 20c are oriented to face each other and define or delimit the receiving space 24. Figure 5 As can be seen, the second mounting surface 20b and the third mounting surface 20c are oriented to face each other and define or delimit the receiving space 24.

[0070] Instead of Figure 5 the T-shaped cross-sectional shape shown by way of example, the connecting member 20 may also have an L-shaped cross-sectional shape (not shown). For this purpose, both the second web 26 and the optional third web 27 are provided on a lateral end region 28 of the first web 25 (not shown).

[0071] The connecting member 20 is formed of a metallic material, for example, formed of titanium, a titanium alloy, aluminum, an aluminum alloy, or a similar metallic material.

[0072] As Figure 1 、 Figure 2 and Figure 4As shown by way of example, the attachment member 30 is similarly formed as an elongated part, in particular in the form of a profile member, like the door frame member 10. In Figure 1 , Figure 2 and Figure 4 the attachment member 30 shown by way of example has a linear or straight longitudinal extent. However, it goes without saying that the attachment member 30 can also have a curved longitudinal extent (not shown). In Figure 2 and Figure 4 the attachment member 30 shown by way of example has a U-shaped or C-shaped cross section. Here, the cross section is formed by a transverse web 31, a first side web 32 and a second side web 33. Here, the side webs 32, 33 extend along one another, in particular parallel to one another, and are connected by the transverse web 31. As Figure 4 shown by way of example, the transverse web 31 can have a reduced width in the first end portion 30A of the attachment member 30.

[0073] The attachment member 30 is formed from a fiber-reinforced thermoplastic material, for example one having polyetheretherketone (abbreviated as PEEK), polyphenylene sulfide (abbreviated as PPS), polyethyleneimine (abbreviated as PEI) or a similar thermoplastic material as the matrix material M. Reinforcing fibers F, such as carbon fibers, glass fibers, ceramic fibers, aramid fibers, boron fibers, mineral fibers, natural fibers or plastic fibers or mixtures thereof, are embedded in the matrix material M.

[0074] In Figure 2 it can be seen that the structural member 40 is likewise formed as an elongated part, which optionally has an arcuate or substantially curved longitudinal extent. The structural member 40 can in particular be designed as a profile member. In Figure 2 the structural member 40 shown by way of example has a substantially Z-shaped cross section, which is formed by a longitudinal web 41, a first side web 42 and a second web 43, the first side web 42 protruding laterally relative to the first side from the longitudinal web 41 at the first end of the longitudinal web 41, and the second side web 43 protruding laterally relative to the second side from the longitudinal web 41 at the second end of the longitudinal web 41. As Figure 2 shown by way of example, it can be provided that the cross section of the structural member 40 is formed by two L-shaped profile segments overlapping in the region of the longitudinal web 41.

[0075] The structural member 40 is formed from a fiber-reinforced thermoplastic material, for example one having polyetheretherketone (abbreviated as PEEK), polyphenylene sulfide (abbreviated as PPS), polyethyleneimine (abbreviated as PEI) or a similar thermoplastic material as the matrix material M. Reinforcing fibers F, such as carbon fibers, glass fibers, ceramic fibers, aramid fibers, boron fibers, mineral fibers, natural fibers or plastic fibers or mixtures thereof, are embedded in the matrix material M.

[0076] In particular, as Figure 3 shown, the optional door stop 60 typically has an engagement projection 62. The engagement projection 62 is provided as a support or engagement surface for a door (not shown) of the aircraft. As Figure 3 shown by way of example, the door stop 60 may have a base plate 61 from which the engagement projection 62 projects. The door stop 60 is typically formed of a metallic material, such as formed of titanium, titanium alloy, aluminum, aluminum alloy, etc.

[0077] In particular, as Figure 4 shown, the inner surface 10a of the door frame member 10 and the connecting member 20 are fastened to each other, in particular welded to each other. In addition, the connecting member 20 and the attachment member 30 are fastened to each other, in particular welded to each other. Here, in particular, the first fitting surface 20a of the connecting member 20 abuts against the inner surface 10a of the door frame member 10. For example, the first fitting surface 20a may abut against or be welded to a part of the inner surface 10a of the door frame member 10 formed by the inner surface 11a of the first web 11 of the door frame member 10 extending between the side webs 12, 13. Similarly as Figure 4 shown, the second fitting surface 20b provided on the second web 26 of the connecting member 20 abuts against the first surface 30a of the attachment member 30, in particular against the transverse web 31 of the attachment member 30.

[0078] If a connecting member 20 having an optional third web 27 is used in Figure 4 , the second surface 30b of the attachment member 30 located opposite the first surface 30a abuts against the optional third fitting surface 30c of the connecting member 20.

[0079] Similarly as Figure 4 shown, the connecting member 20 can in particular be positioned relative to the door frame member 10 or fastened to the inner surface 11a of the longitudinal web 11 of the door frame member 10 by means of the first fitting surface 20a such that the second fitting surface 20b of the connecting member extends transversely with respect to the side webs 12, 13 of the door frame member 10. Thus, in particular, it can be provided that the second web 26 and possibly the optional third web 26 extend in a direction extending from the first longitudinal web 12 in the direction of the second longitudinal web 13 of the door frame member. This particularly provides the advantage that the first end portion 30A of the attachment member 30 can slide between the first web 12 and the second web 13 of the door frame member 10.

[0080] As Figure 1 and Figure 2As shown, the connecting member 30 extends between the door frame member 10 and an optional structural member 40. The structural member 40 and the door frame member 10 extend along each other, preferably parallel to each other. The second end portion 30B of the attachment member 30, which is located opposite the first end portion 30A with respect to the longitudinal extent of the attachment member 30, is fastened, in particular welded, to the second mounting surface 20b of a further connecting member 50. The second end portion 30B of the attachment member 30 can also be fastened, in particular welded, to an optional third mounting surface 20c of the further connecting member 50. This further connecting member 50 has the same construction as the connecting member 20 based on Figure 5 described. The first mounting surface 20a of the further connecting member 20 abuts against the inner surface 40a of the structural member 40 and is fastened, in particular welded, thereto.

[0081] Similarly as Figure 2 shown, the connecting member 50 can in particular be positioned relative to the structural member 40 or fastened to the inner surface 40a of the structural member 40 via the mounting surface 20a such that the second mounting surface 20b of the connecting member extends transversely with respect to the side webs 42, 43 of the structural member 40.

[0082] As Figure 1 and Figure 2 shown by way of example, a plurality of attachment members 30 can be provided, each attachment member 30 being connected to the door frame member 10 in the manner described above and possibly to the optional structural member 40. As Figure 1 and Figure 2 shown, the individual attachment members 30 are arranged spaced apart from each other along the longitudinal extent L of the door frame member 10. In this way, a mechanically robust ladder-like structure of the frame part 1 is formed.

[0083] In particular, it can be seen in Figure 3 that a door stop 60 is provided on the outer surface 10b of the door frame member 10 opposite the inner surface 10a, wherein an engagement projection 62 projects with respect to the outer surface 10b of the door frame member 10. In particular, as Figure 3 shown by way of example in Figure 3 the door stop 60 shown abuts against the outer surface 10b of the door frame member 10 with its optional base plate 61 and has four grooves through which a lead screw 63 extends through the door frame member 10, in particular through the transverse web 11 of the door frame member 10. Optionally, the door stop 60 is arranged with respect to the longitudinal extent of the door frame member 10 so as to overlap the first mounting surface 20a of the connecting member 20, in particular completely. In this case, the screws 63 also each extend through the first web 25 of the connecting member 20.

[0084] As Figure 1 As shown by way of example and briefly described in the introduction, the frame member 1 designed in the above manner can in particular be installed to form a door frame structure 100. The first transverse strut 103 extends between the door frame member 10 of the first frame member 1, 101 and the door frame member 10 of the second frame member 1, 102, wherein the first transverse strut 103 is fastened respectively on the first end portion 10A of the door frame member 10 of the first frame member 1, 101 and on the first end section 10A of the door frame member 10 of the second frame member 1, 102. The second transverse strut 104 extends between the door frame member 10 of the first frame member 1, 101 and the door frame member 10 of the second frame member 1, 102, wherein the second transverse strut 104 is fixed respectively on the second end portion 10b of the door frame member 10 of the first frame member 1, 101 and on the second end portion 10B of the door frame member 10 of the second frame member 1, 102, the second end portion 10b being opposite to the first end portion 10A with respect to the longitudinal extent L of the door frame member 10, and the second end portion 10B being opposite to the first end portion 10A with respect to the longitudinal extent L of the door frame member 10. As Figure 1 shown, the door frame member 10 and the transverse struts 103, 104 together define a door opening 105 which, when the door frame structure 100 is installed in an aircraft (not shown), is arranged for loading and unloading of the aircraft or as a passenger entrance or passenger exit. An optional door stop 60 projects into the door opening 105 in this case.

[0085] A method for manufacturing the frame member 1 for a door frame structure 100 for an aircraft door will be described below. In particular, the above-mentioned frame member 1 can be manufactured by this method. Therefore, reference is made to Figures 1 to 5 the object shown in

[0086] In this method, a first connection area 21 is formed on the first assembly surface 20a by generating a surface texture of the first assembly surface 20a of the connection member 20. Furthermore, a second connection area 22 is formed on the second assembly surface 20b by generating a surface texture of the second assembly surface 20b of the connection member, and it is additionally possible that a third connection area 23 is formed on the third assembly surface 20c by generating a surface texture of the third assembly surface 20c.

[0087] During the formation of the respective connection areas 21, 22, 23, the respective assembly surfaces 20a, 20b, 20c of the metal material of the connection member 20 are roughened, that is to say provided with a surface topography having cavities or depressions and protrusions. This step is carried out in Figure 6This is schematically illustrated by way of example. A laser beam B is generated by a laser source 200, and the laser beam B is guided onto the corresponding mounting surfaces 20a, 20b, 20c by means of an optical device 202 that guides and / or focuses the laser beam B and / or filters laser radiation in certain wavelength ranges through an optical waveguide 201 (e.g., in the form of an optical fiber). In this way, the metallic material of the connecting part 20 melts in the regions of the corresponding mounting surfaces 20a, 20b, 20c. After this laser treatment, the metallic material solidifies again. In this way, a roughened surface is formed. As an alternative to this laser treatment, the respective connecting regions 21, 22, 23 can also be achieved by electrochemically roughening the corresponding mounting surfaces 20a, 20b, 20c.

[0088] Figure 7 A detail view of the connecting regions 21, 22, 23 of the connecting part is schematically shown. It can be seen that due to the roughening, protrusions 21P, 22P, 23P and depressions 21V, 22V, 23V are formed in the regions. The first connecting region 21, the second connecting region 22 and the possible third connecting region 23 of the connecting part 20 can each particularly be formed with a surface topography having a height difference d21, d22, d23 between 1 μm and 8 μm. Accordingly, the respective connecting regions have a thickness between 1 μm and 8 μm. In particular, due to the roughening, incisions or cavities 21V, 22V, 23V are formed in the corresponding mounting surfaces 20a, 20b, 20c, and their depths are between 1 μm and 8 μm. These height differences d21, d22, d23 can be seen in Figure 10 and will be referred to in detail below with reference to Figure 10 .

[0089] In addition, as shown by way of example and described in detail above in Figure 4 , the method includes placing the first mounting surface 20a of the connecting part 20 against the door frame member 10, particularly against the inner surface 10a of the door frame member 10, preferably against the inner surface 11a of the transverse web 11 of the door frame member 10.

[0090] In addition, as described in detail above, the attachment member 30 is placed against the second mounting surface 20b of the connecting part 20, and in particular the first surface 30a in the region of the first end portion 30A of the attachment member 30 is placed against the second mounting surface 20b. Optionally, the first end portion 30A of the attachment member 30 is slid into the receiving space 24 of the connecting part 20, which, as described above, is located between the second and optional third connecting surfaces 20a, 20b, 20c.

[0091] Optionally, it can be stipulated that the first mounting surface 20a of the connecting part 20 is placed against the joint area 15 of the inner surface 10a of the door frame member 10, the second mounting surface 20b of the connecting part 20 is placed against the joint area 35 of the first surface 30a of the attachment member 30, and possibly the third mounting surface 20c of the connecting part 20 is placed against the joint area of the second surface 30b of the attachment member 30. In particular, as will be discussed in more detail below Figure 10 it can be seen that in the corresponding joint areas 15, 35, the door frame member 10 and the attachment member 30 are formed only of the thermoplastic matrix material M in their respective joint areas 15, 35 of the cross-sectional edge area, without the reinforcing fiber F. In particular, the door frame member 10 and the attachment member 30 are formed of the thermoplastic matrix material M at least in the joint areas 15, 35 in a thickness range d15, d35 between 1 μm and 8 μm from the respective surfaces 10a, 30a, 30b.

[0092] To fasten the door frame member 10 and the attachment member 30 to the connecting part, the connecting part 20 and the door frame member 10 are welded, and the connecting part 20 and the attachment member 30 are welded. In each case, a composite welded joint is formed between the metallic material of the connecting part 20 and the thermoplastic matrix material M of the attachment member 30 and the door frame member 10.

[0093] In Figure 8 the welding of the attachment member 30 and the connecting part 20 is schematically shown. The welding of the door frame member 10 and the connecting part 20 is carried out similarly. For welding, a laser source 200 is used to generate a laser beam B, and the laser beam B is guided to the corresponding connection areas 21, 22, 23 or the contact areas between the attachment member 30 and the connecting part 20 or between the door frame member 10 and the connecting part 20 by means of an optical waveguide 201 and via an optical device 202. This can be achieved by guiding the laser beam B to the webs 25, 26, 27 of the connecting part 20 and guiding the laser beam B to the door frame member 11 or the attachment member 30. Due to the energy introduced by the laser beam B, the thermoplastic matrix material M of the attachment member 30 or the door frame member 10 respectively becomes a plastically deformable state, in particular a molten state. As a result, the thermoplastic matrix material M enters the corresponding connection areas 21, 22, 23 of the connecting part 20 and solidifies there.

[0094] Figure 8 A welding automation device 300 is schematically shown by way of example, which has a laser source 200, an optical waveguide 201, an optical device 202, a chassis 301 and a manipulator 302. The chassis 301 can have a plurality of drive wheels (such as Figure 8as shown), and enables the welding automation device 300 to move on the ground. The laser source 200 and the manipulator 302 are each connected to the chassis 301. The manipulator 302 has a plurality of moving arms 303 that can move relative to each other, and the optical device 202 is disposed on the last moving arm 303. In this way, the laser beam B can be guided to different positions in an automatic manner, which is beneficial to the manufacture of the frame member 1.

[0095] Generally, the same laser source 200 can be used to form the connection regions 21, 22, 23 of the connecting member 20 and for welding. Different characteristics of the laser beam B can be generated by different optical devices 201.

[0096] As an alternative to the described laser welding, the welding of the connecting member 20 to the door frame member 10 and the attachment member 30 can also be performed by ultrasonic welding or induction welding. Generally, sufficient energy to melt the thermoplastic matrix material needs to be supplied to the connection regions 21, 22, 23.

[0097] Figure 9 and Figure 10 respectively show in detail cross-sectional views of the composite welded joints formed in this way between the attachment member 30 and the connecting member 20 or between the door frame member 10 and the connecting member 20, where Figure 10 is shown in detail by Figure 9 the region denoted by the letter character Y in. In particular, it can be seen in Figure 10 that due to the melting of the thermoplastic matrix material M in the regions of the corresponding surfaces 10a, 30a, 30b, the matrix material M enters the cavities 21V, 22V, 23V of the corresponding connection regions 21, 22, 23 of the connecting member 20 and solidifies there. In this way, at least a partially positively locking joint is produced between the metallic material of the connecting member 20 and the thermoplastic material of the door frame member 10 or the attachment member 30. The cavities 21V, 22V, 23V partially have undercuts and / or extend in different directions respectively. This additionally increases the mechanical load-bearing capacity of the welded joint.

[0098] In Figure 10 it can also be seen that the thermoplastic matrix material M can be melted particularly in the thickness ranges d15, d35 between 1 μm and 8 μm. As shown in Figure 10 there are no reinforcing fibers F within this thickness range. In this way, damage, deformation and misalignment of the reinforcing fibers F due to the welding process are prevented.

[0099] Figure 10Also shown is that the height differences d21, d22, d23 of the surface configurations of the respective mounting surfaces 20a, 20b, 20c of the connecting member 20 can likewise optionally be between 1 μm and 8 μm. In particular, it can be provided that the height differences d21, d22, d23 of the surface configurations of the respective mounting surfaces 20a, 20b, 20c of the connecting member 20 are respectively within a range between 50% and 90% of the thickness ranges d15, d35 of the door frame member 10 or the attachment member.

[0100] The second end portion 30B of the attachment member 30 and the optional structural member 40 can be welded to the additional connecting member 50 in the same manner as described above for the first end portion 30A of the attachment member 30 and the door frame member 50 and the connecting member 20.

[0101] Although the present invention has been discussed by way of example based on exemplary embodiments above, the present invention is not limited thereto, but can be modified in various ways. In particular, combinations of the above exemplary embodiments are also conceivable.

Claims

1. A method for manufacturing a frame member (1) of a door frame structure (100) for an aircraft, the frame member defining a door opening, the method having the following steps: Forming a first connection region (21) on a first assembly surface (20a) by generating a surface structure of the first assembly surface (20a) of a connection member (20), wherein the connection member (20) is formed of a metallic material; Forming a second connection region (22) on a second assembly surface (20b) by generating a surface structure of the second assembly surface (20b) of the connection member, wherein the second assembly surface (20b) extends transversely with respect to the first assembly surface (20a); Placing the first assembly surface (20a) of the connection member (20) against a door frame member (10) made of a fiber-reinforced thermoplastic material; Welding the connection member (20) and the door frame member (10), wherein the thermoplastic material of the door frame member (10) enters the first connection region (21) of the connection member (20); Placing an attachment member (30) against the second assembly surface (20b) of the connection member (20), wherein the attachment member (30) is formed of a fiber-reinforced thermoplastic material; And Welding the connection member (20) and the attachment member (30) on the opposite side of the connection member where the door frame member and the connection member are welded together, wherein the thermoplastic material of the attachment member (30) enters the second connection region (22) of the connection member (20).

2. The method according to claim 1, wherein, The formation of the first connection region (21) and the second connection region (22) of the connection member (20) is carried out respectively by melting the metallic material on the first assembly surface (20a) and the second assembly surface (20b) by means of a laser beam (B), or by electrochemically roughening the first assembly surface (20a) and the second assembly surface (20b).

3. The method according to claim 1 or 2, wherein The welding of the connection member (20) to the door frame member (10) and the attachment member (30) is carried out respectively by laser welding, ultrasonic welding or induction welding.

4. The method according to claim 1 or 2, wherein The first connection region (21) and the second connection region (22) of the connection member (20) are each formed with a surface topography having a height difference (d21; d22) between 1 μm and 8 μm.

5. The method according to claim 1 or 2, further having the following steps: Forming a third connection region (23) on a third assembly surface (20c) by generating a surface structure of the third assembly surface (20c) of the connection member, wherein the third assembly surface (20c) is disposed opposite to and oriented towards the second assembly surface (20b) such that the second assembly surface (20b) and the third assembly surface (20c) form a receiving space (24); While placing the attachment member (30) against the second assembly surface (20b) of the connection member (20), placing the attachment member (30) against the third assembly surface (20c) of the connection member (20) by sliding the attachment member (30) into the receiving space (24). and Welding the connecting member (20) and the attachment member (30) at the second and third mounting surfaces (20b, 20c) of the connecting member (20), wherein the thermoplastic material of the attachment member (30) enters the second and third connection regions (22, 23) of the connecting member (20).

6. The method according to claim 1 or 2, wherein Placing the first mounting surface (20a) of the connecting member (20) against the joint region (15) of the surface (10a) of the door frame member (10), and placing the second mounting surface (20b) of the connecting member (20) against the joint region (35) of the surface (30a) of the attachment member (30), wherein the door frame member (10) and the attachment member (30) are made of thermoplastic material in a thickness range (d15, d35) between 1 μm and 8 μm from the respective surfaces in their respective joint regions (15; 35).

7. The method according to claim 1 or 2, wherein The door frame member (10) has a U-shaped or C-shaped cross-section formed by a transverse web (11) and two side webs (12; 13), and wherein the first mounting surface (20a) of the connecting member (20) is placed against the inner surface (11a) of the longitudinal web (11) of the door frame member (10) that extends between the side webs (12; 13).

8. The method according to claim 7, wherein, Placing the connecting member (20) such that the first mounting surface (20a) is against the inner surface (11a) of the longitudinal web (11) of the door frame member (10), so that the second mounting surface (20b) of the connecting member extends transversely with respect to the side webs (12; 13) of the door frame member (10).

9. The method according to claim 1 or 2, wherein The fiber-reinforced thermoplastic material contains polyether ether ketone, polyphenylene sulfide or polyethylene imine as the matrix material.

10. A frame member (1) for a door frame structure (100) of an aircraft, the frame member defining a door opening and having: A door frame member (10) made of fiber-reinforced thermoplastic material; A connecting member (20) made of a metallic material, which is welded to the inner surface (10a) of the door frame member (10); and An attachment member (30) made of fiber-reinforced thermoplastic material, which is welded to the connecting member on the opposite side of the connecting member where the door frame member and the connecting member are welded together.

11. The frame member (1) according to claim 10, wherein, The connecting member (20) is formed as an L-shaped or T-shaped angle member, and wherein the connecting member (20) is fastened to the door frame member (10) through the first mounting surface (20a) and to the attachment member (30) through the second mounting surface (20b).

12. The frame member (1) according to claim 10 or 11, wherein, The door frame member (10) has a U-shaped or C-shaped cross-section formed by a transverse web (11) and two side webs (12; 13), and wherein the connecting member (20) is fastened to the inner surface (11a) of the transverse web (11) of the door frame member (10) that extends between the side webs.

13. The frame member (1) according to claim 10 or 11, wherein, The frame member (1) further has a structural member (40) made of a fiber-reinforced thermoplastic material and a further connecting member (50) made of a metallic material, the further connecting member being welded to the inner surface (40a) of the structural member (40) and to the end portion (30B) of the attachment member (30) that is opposite the door frame member (10).

14. The frame member (1) according to claim 10 or 11, wherein, The frame member (1) further has a door stopper (60), the door stopper (60) being provided on the outer surface (10b) of the door frame member (10) that is opposite the inner surface (10a), and having an engaging protrusion (62) protruding from the outer surface (10b).

15. An aircraft door frame structure (100), comprising: a first frame member, the first frame member being the frame member according to any one of claims 10 to 14; a second frame member, the second frame member being the frame member according to any one of claims 10 to 14; a first transverse strut (103) extending between the door frame member (10) of the first frame member (1; 101) and the door frame member (10) of the second frame member (1; 102), and being fastened at opposite ends thereof to the first end portion (10A) of the door frame member (10) of the first frame member (1; 101) and to the first end portion (10A) of the door frame member (10) of the second frame member (1; 102) respectively; and a second transverse strut (104) extending between the door frame member (10) of the first frame member (1; 101) and the door frame member (10) of the second frame member (1; 102), and being fastened at opposite ends thereof to the second end portion (10B) of the door frame member (10) of the first frame member (1; 101) and to the second end portion (10B) of the door frame member (10) of the second frame member (1; 102) respectively.

Images