Lightweight sandwich-type construction component or element and method of manufacturing said component or element

Abstract

Sandwich-type construction component or element with a lightweight structure and method for manufacturing said component or element The invention relates to a sandwich-type construction component or element (2) comprising a core (12) provided with two flattened faces (8a) facing away from each other, and at least one first covering layer (14a) which is connected to said core (12), ensures the mechanical stabilization of said component (2) and is provided with at least one fibrous component (16a-16g) containing fibers (18). At least one (8a) of said flattened faces is lined with the first covering layer (14a), such that only a filling zone (20) of this face (8a) is covered by said first layer (14a), leaving a free uncovered zone (22), said face (8a) not being lined with any other layer. Said core (12) is accessible in said free zone (22), at the level of this flattened face (8a), from a surrounding space (24).Figure to be published with the abstract: Fig. 1.

Description

Title of the invention: Sandwich-type construction component or element with a lightweight structure and method of manufacturing said component or element

[0001] The present invention relates to a sandwich-type component or construction element (hereinafter generally referred to simply as a "sandwich-type component"), in particular intended to be used, in accordance with its intended purpose, in a passenger compartment of an aircraft, in particular of an electric vertical take-off and landing vehicle, abbreviated to: eVTOL (for "electrical vertical take-off and landing vehicle"), an Anglo-Saxon abbreviation which will be used throughout the present description.

[0002] From document CA 2 138 775 C, a reinforced structure of the foam core sandwich type is known, comprising oppositely facing cover layers, a foam core interposed therebetween, and tau-shaped elements which are encapsulated in said core, extend between said oppositely facing cover layers, and form a support structure inside said core, between said layers.

[0003] The object of the invention is to propose improvements made to a component or construction element of the sandwich type or with a sandwich structure.

[0004] This sandwich-type component or construction element is presented, in particular, as an internal structural part of an aircraft, which aircraft is in particular an airplane, in particular a small aircraft, specifically an eVTOL. In other words, said component or element is respectively designed or arranged as an internal structural part, in particular in accordance with its intended purpose for the corresponding aircraft.

[0005] The sandwich-type component or construction element comprises a core provided with two flattened faces, which core thus offers a flat extent, so that it appears as a flattened structural part. Therefore, in particular, the surface area of said flattened faces is notably (powers of ten) greater than the remaining surface area of the core, i.e. the marginal surfaces thereof. Said core is in particular a honeycomb core or a foam core.

[0006] In the present case, the meaning "flattened face" must be interpreted broadly and is intended to mean only that it is one of the two main surfaces of the core with a comparatively large surface area, and specifically not the lateral / frontal margins / marginal surfaces of said core which are provided with a comparatively small surface area. It is in no way imperative that the flattened faces are flat, but they can also, on the other hand, have a curvilinear / angled / etc. path. In other words, it can also be a core of a curved panel / a curved component of the sandwich type.

[0007] The sandwich-type component or construction element comprises at least one first covering layer, which first layer is connected to the core, ensures the respective mechanical stabilization of said component or said core, and is provided with at least one fibrous constituent containing fibers. The latter are, in particular, glass or carbon fibers. Said fibrous constituent is in particular designed in the form of a prepreg as is conventional, in aeronautics, for structural parts of the sandwich type intended for passenger compartments. The term "connected" must be understood, for example, as glued or aggregated in a thermoforming process, as is usual in the presence of such structural parts of the sandwich type.

[0008] At least one of the flattened faces of the core is lined, respectively, with the first covering layer or with one of these, that is to say that it is connected to it and is, in part, covered by the latter. Such a lining of the flattened face concerned, by the first covering layer, is carried out as follows: only a lining zone, materialized by one or more surface section(s) of this flattened face, is covered by said first layer. This means that a free zone, similarly materialized by one or more surface section(s), remains respectively on this flattened face, or on the core, which is consequently not lined, in said free zone, by said first layer which only lines said core in said lining zone. The flattened face concerned is also not lined with any other layer, in particular with any other substrate-forming layer.As a result, said flattened face in question is not in particular lined with any layer. As a result, the core is, or remains respectively accessible in the free zone, at the level of this flattened face, from the space surrounding the sandwich-type component. In the free zone, said core would therefore be visible to an observer of the flattened face in question. Said lining zone and said free zone jointly provide the entire surface area of said flattened face in question.

[0009] Alternatively, the flattened face concerned is, at least, not furnished with any substrate-forming layer. This is to be interpreted as “unfurnished” in the spirit of the present invention. This also applies, rationally, to the statement of “accessibility”. An additional layer is presented, for example, as a purely decorative layer or as a very light layer devoid of any respectively essential or significant substrate function, for example a purely decorative lamination or lacquering. “Visibility” then ceases, strictly speaking, to be conferred on the core. Expressed differently, said core could also be protected by a layer only very light at the level of the “free zones” » (free from a first covering layer). Therefore, the meaning “unfilled” includes the filling with a layer that is insignificant as regards a substrate function.

[0010] Such a first covering layer may also be similarly arranged on the second flattened face, or said second face may, in this way, be respectively connected to a first additional covering layer, or furnished with the latter.

[0011] This results in accordance with the invention, at the level of the flattened face considered thus filled by the first covering layer (the free zone then remaining), the effect consisting in that a mechanical stabilization of the core is, indeed, established in the filling zones (namely under the action of the fibrous constituents), but that the free zones nevertheless remain uncovered. No first covering layer over the entire surface is consequently present. This governs a weight saving. In this case, however, the filling zone(s) can be selected in such a way that the mechanical robustness of the sandwich-type component is nevertheless sufficient.For example, only load paths that are only foreseeable in service, in said sandwich-type component or construction element, can be reinforced by the first covering layer, areas with lower or no mechanical stresses, as expected, remaining however unfilled. This hardly involves any mechanical disadvantages in terms of stability, load capacity, durability, etc., compared to a filling known in practice and carried out, over the entire surface of the flattened face in question, using a first covering layer over the entire surface.

[0012] In a preferred embodiment of the invention, the lining area occupies at least 10% (and in particular, at most, 50%) of the total surface area of the flattened face in question. In particular in the case of very small / highly stressed structural parts, for example, it should be assumed that said lining area could also increase beyond 50%. In other words, a non-insignificant part of the total surface area is covered by the first covering layer, i.e. it forms the lining area of this flattened face. The same applies to the free area. This therefore results in noticeable, or even essential, weight savings compared to lining the entire surface area of the flattened face in question with a first covering layer.

[0013] In a preferred embodiment of the invention, at least one of the fibrous constituents (which applies in particular to a plurality or all of the latter) comprises fibers with an exclusively unidirectional orientation. The adverb “exclusively” then refers to the respective portion of fibers contained by said fiber component. Expressed differently, therefore, the corresponding fiber component does not contain any other fibers with a unidirectional / * parallel orientation. Said component is in particular a "UD fiber component" (unidirectional) with oriented fibers, for example as a corresponding fiber ribbon, in which the fibers extend exclusively in the direction of the longitudinal extent of said ribbon. Such ribbons are particularly suitable for the establishment of a corresponding selective reinforcement of a flattened face, in the filling zone, using the first covering layer. They can, in particular, absorb tensile forces at this location.

[0014] In a preferred embodiment of the invention, at least one of the fiber components (which applies in particular to a plurality or all of them) comprises interwoven fibers. In other words, it is then a woven fiber component, for example a commercially available woven prepreg. In this way, regions of the first covering layer which are concretely formed by corresponding fiber components can ensure a particularly stable mechanical reinforcement of the core, and thus of the sandwich-type component. In this case, forces are absorbed in several directions.

[0015] In a preferred variant of this embodiment, at least one of the fibrous constituents (which applies in particular to a plurality or all of the latter) is arranged, with intersecting fibers, on an edge of the flattened face in question. In other words, the edge of said face in question is thus of a particularly stable mechanical design / capable of withstanding stresses in the sandwich-type component.

[0016] In a preferred variant of this embodiment, the sandwich-type component contains at least one mechanical coupling element mechanically connected, rigidly, to the remaining part of said component. Such a coupling element is, for example, a retaining member, a clip, an integrated part, etc., and serves to connect said component, with the ability to withstand mechanical stresses, to other elements such as the fuselage of an aircraft, for example. At least one of the fibrous constituents with interwoven fibers (which applies in particular to a plurality or all of the latter) is then associated with said coupling element. "Associated" means that said constituent with interwoven fibers mechanically exerts a reinforcing effect concerning the mechanical connection of said coupling element with the remaining part of said sandwich-type component.Thus, the corresponding fibrous constituent is implanted in particular on said coupling element and / or in the immediate vicinity thereof, and / or between the latter and the core, and / or in the region of said coupling element. For example, the fibrous constituent concerned materializes in particular, on the face. flattened, a surface section which is larger than a base surface of the coupling element, and in the center of which said element is then arranged. As a result, a particularly stable mechanical connection is established between the coupling element and the remaining part of the sandwich-type component or, respectively, that said element is implanted on said component / supported on said component / connected to it with sufficient mechanical rigidity.

[0017] In a preferred embodiment of the invention, at least one of the fiber components (which applies in particular to a plurality or all of them) is configured as a ribbon. This applies to components with both unidirectional and interlaced fibers. Expressed differently, corresponding fiber components are respectively applied or deposited, in the form of ribbons, on the corresponding flattened face of the sandwich-type component. On the basis of such ribbons, it is particularly suitable to arrange a corresponding first covering layer and to create free zones on said flattened face. In this way, in particular, force paths can be well established.

[0018] In a preferred variant of this embodiment, at least a part of at least one of the first covering layers (or both), in particular the entirety of this first layer, is designed as fiber components configured as ribbons and arranged in the form of a crisscross assembly on the flattened face in question. In other words, these are at least two fiber components which cross or overlap end to end / form a "bifurcation" in said assembly. This allows, for example, the creation, at least as part of the filling region, of crisscross assembly structures which are developed on the basis of construction technology or other fields of mechanics and which establish sufficient mechanical stability in the sandwich-type component by means of comparatively small filling regions (constitutive part of the total surface area of the flattened face).

[0019] In a preferred embodiment of the invention, at least a part of at least one of the first covering layers (or both), in particular the entirety of this first layer, is of single-layer design with regard to the fiber components. This means that only one fiber component in question is placed, on the corresponding flattened face, at one location of said covering layer. In this case, by "single-layer", it is to be understood that possible crossings / bifurcation points, etc. of fiber components (for example in a crisscross assembly structure, see above) are deemed to be excluded. In this case, two or more layers of fiber components may also be stacked on top of each other in zones. Apart from this, ribbons or surface sections that overlap / stack on top of each other are not present, however.

[0020] In a preferred embodiment of the invention, at least a part of at least one of the first covering layers (or both), in particular the entirety of this first layer, is produced in the outcrop of the core. In other words, said layer is pressed into said core at the location concerned, for example forcefully integrated by deformation of the latter, of an extent suitable for giving rise, at the level of the corresponding flattened face, to a surface of the entire sandwich-type component which is smooth, i.e. free of discontinuities (with a continuous derivative in the mathematical sense), in particular also free of inflections. In other words, consequently, said component is not prominent in the region of the fibrous constituents or, respectively, of the first covering layer.This thus makes it possible to obtain a smooth surface on the relevant flattened face of said component, which provides, for example, a particularly attractive optical appearance and also facilitates / enables demolding from a mold used for the manufacture of said sandwich-type component.

[0021] In a preferred embodiment of the invention, at least one, in particular precisely one of the flattened faces, and the core accordingly, is covered with a second covering layer. In particular in the case where a first covering layer is also present on this flattened face, the second layer covers both the core and the first layer, i.e. it forms a covering layer further away from said core than said first layer. A corresponding second covering layer allows any other arrangements of the sandwich-type component, as regards its surface. In this case, for example, said second layer does not necessarily have to satisfy the stress paths / mechanical boundary conditions of the first layer, but can for example be focused / optimized by targeting the optical appearance of said sandwich-type component.

[0022] In a preferred variant of this embodiment, at least one, in particular precisely one of the flattened faces is respectively covered, in full or over the entire surface, by the second covering layer. This provides, on the sandwich-type component, a flattened face in which the core is no longer accessible from the surrounding space, and in particular is no longer visible. As a result, a corresponding flattened face provided with the second covering layer covering the entire surface can, for example, have a particularly attractive optical design by being, for example, lacquered / laminated, etc.

[0023] Thus, with regard to the second covering layer, a filling zone is obtained (in the aforementioned meaning of the first covering layer) which corresponds to the entire surface area of the flattened face, a free zone then not being present at any location on this flattened face with regard to said second layer.

[0024] In a preferred variant of this embodiment, one of the flattened faces, covered by the second covering layer over the entire surface, is a visible face of the sandwich-type component when said component is in a state of assembly in accordance with its intended purpose. The state of assembly in accordance with the intended purpose is a state in which said sandwich-type component is to be installed at a later stage, in an application case, for example to be integrated into an aircraft. Said component is, for example, an internal trim structural part located, respectively, in a passenger compartment or in a passenger cabin of an aircraft. The flattened face concerned then points towards the passenger compartment / cabin, and can be observed by persons staying in the aircraft, respectively in said passenger compartment / cabin.

[0025] The flattened face facing away then constitutes, in particular, a face covered only by the first covering layer. In this case, although the core is accessible from the surrounding space and is also visible, this is not a problem since it is not a visible face in the integrated state, and its visual appearance is therefore not relevant. Weight savings can, in this way, be achieved in a particularly advantageous manner.

[0026] In a preferred variant of this embodiment, at least one of the second covering layers contains a foam component or structural part. In other words, this is a foam layer in this case. Foam structural parts can be produced in a particularly simple manner as a covering layer, are similarly light and can be subjected to a surface treatment, for example, to be putty with a spatula, lacquered, etc. An optically attractive, yet light, sandwich-type component can be created in this way.

[0027] The object sought by the invention is also achieved by a method of manufacturing a component or a construction element of the sandwich type according to the invention, in which method the core of said component is primed. In the sequence, at least one of the flattened faces of said core is lined with the first covering layer in such a way that said core remains accessible in the free zone, at the level of this flattened face, from the surrounding space.

[0028] The sandwich-type components or construction elements according to the invention are created according to said method.

[0029] The method and at least part of its possible embodiments, as well as the respective advantages, have already been explained, by analogical comparison, in the context of the component or construction element of the sandwich type according to the invention.

[0030] The invention is based on the experiences acquired, the observations, and even the reflections set out below, and also embraces the preferred embodiments which follow, which are also designated by "the invention" in a partly simplified manner. Said embodiments may then also contain parts or combinations of the embodiments mentioned above, or correspond to the latter and / or, where appropriate, also include embodiments not mentioned until now.

[0031] In accordance with the invention, ultimately, sandwich-type components or construction elements with partial filling (by prepregs) or, respectively, partial filling of sandwich-type components or construction elements are obtained.

[0032] Instead of lining the entire surface area, on the front and rear faces of the core material, only partial lining is carried out with the first covering layer (UD or woven prepregs, for example), in order to obtain a structural part whose weight and load are optimized. If absolutely necessary for subsequent decoration, the visible face can also, as up to now, be provided with a second integral covering layer (prepreg layer).

[0033] A possibility of lightweight structural organization is therefore proposed in which the lining with continuous layers is dispensed with, at least on one flattened face, and the required robustness of the structural parts is generated by the partial deposition of fibers, in particular oriented ones.

[0034] A possible application of this inventive idea, and more generally of the objects of the invention described above, in a concrete product is presented, for example, as parts or pieces of internal trim dedicated to airplanes or flying taxis.

[0035] This results, in particular, in an ultra-lightweight embodiment for internal structural parts of eVTOLs. By using the sandwich-type components or construction elements according to the invention and their manufacturing method, internal cladding structural parts for aerial vehicles and / or internal cladding of eVTOLs are thus obtained.

[0036] As a result, a filling no longer takes place using integral covering layers on front and rear faces. An open core is no longer visible only at cutting edges / accessible from the surrounding space (in the manner partly customary in practice).

[0037] In this way, particularly in the presence of such structural parts of internal equipment in aircraft, it is not necessary to always use integral layers of fabric prepregs at the stage of manufacturing said parts of equipment.

[0038] This results in the implementation of optimized material provided by load-optimized reinforcements, and by weight savings.

[0039] According to the invention, a filling adapted to the load is carried out, which, however, is not carried out in particular by means of laminates / sandwich-type structures comprising several layers. The particularity then lies in the fact that the material constituting the core is not completely covered by a first covering layer (prepreg), at least on a flattened face. The use of a thin foam layer (second covering layer) reduces the complexity of sanding and spatula filling. Alternatively or additionally, a foam core (which itself contains a foam material) is also generally conceivable.

[0040] In particular, to establish a crisscross assembly on the rear face of the component, recourse is therefore made to the use of unidirectional fiber strips replacing covering layers used to cover surfaces. The surface is then covered by only 10% to 50%, which means a saving in material and weight, of 50% to 90%, of the layer covering the rear face of the mixed sandwich-type component. In this case, part of the material constituting the core is always visible, on the rear face in particular, and is not covered by a layer of prepreg covering the surface.

[0041] Therefore, according to the invention, reinforcements (assigned to the formation of the first covering layer) are not stacked on top of each other in multiple layers, but reinforcements are instead produced, in a single layer, by means of a strip which is, in particular, reinforced with endless fibers. This is not a lattice structure laminated in a mold, knowing that the structure is rather obtained by means of the deposition of fibers, in particular unidirectional ones, and that it can be applied, according to any configurations (shape / structure of the first covering layer), to the material constituting the core.

[0042] One consideration applies in particular: the rear face of internal cladding structural parts or parts, of the sandwich type, is reinforced by unidirectional prepregs made of glass or carbon, etc. The orientation can then be arranged in freely selected rectilinear strip configurations (rectilinear ribbons, which do not precisely follow the surface of the component in space). In this case, use is made either of an individual load-specific / load-matching configuration, or of an optimized geometric packing for a general load distribution. Both the weight of the component and the material used in place, are thus minimal. The front face (visible face pointing towards the passenger) can continue to be covered over the entire surface with a fabric prepreg.

[0043] The reinforcements (first covering layer) are not added to the thickness, but are instead pressed into the material constituting the core (i.e. they are then found "in the flush" of the remaining part of said core), so that the reinforcements applied are not the cause of demolding problems in the pressing process, during the manufacturing process, due to the partial use of the strips.

[0044] The manufactured components are further distinguished, in particular, by a fabric-reinforced edge. Furthermore, fabric-reinforced inserts are used in the region of the retaining members.

[0045] Both honeycomb structures and foam substances are suitable as core material.

[0046] Suitable manufacturing methods are autoclaving, vacuum creation, pressing with cyclic temperature management, and hot in / hot out.

[0047] Other characteristics, effects and advantages of the invention are highlighted by the description of preferred embodiments of the latter, provided below, as well as by the appended schematic drawings in which:

[0048] [Fig-1] is an elevation of a component or building element of the type sandwich, according to one embodiment of the invention, observed from its rear face;

[0049] [Fig.2] is an elevation of the front face of said component or element of construction, including a diagram of its manufacturing process;

[0050] [Fig.3] is a cross-section of said component or building element along line III-III of figures 1 and 2;

[0051] [Fig.4] is a cross-section of a first variant embodiment of said component or construction element;

[0052] [Fig.5] illustrates a second variant embodiment; and

[0053] [Fig.6] is an elevation similar to [Fig.l], showing a third variant of production of said component or construction element.

[0054] [Fig.l] illustrates a component or construction element 2 of the sandwich type taking the form of an internal structural part of an aircraft, an eVTOL in the case considered. Said component 2 or said internal structural part then appears, respectively, as a structural trim part 6 which surrounds a window 4 not illustrated, or even present only in the integrated state. Said component 2 contains a foam core 12, a honeycomb core in this case.

[0055] [Fig.l] shows a first flattened face 8a of the core 12 constituting, at present, the rear face 10 of said core. When, in accordance with its purpose, the latter is integrated into the eVTOL not illustrated, it faces the external wall of the aircraft and is, consequently, not visible to passengers in said eVTOL.

[0056] The sandwich-type component 2 includes a first covering layer 14a which mechanically stabilizes it, which layer 14a comprises a plurality of fibrous constituents 16. Only a small number of the latter bear references, in the figures, in order to provide a good overview. In addition, the numerical references "16" are optionally followed by a lowercase letter for differentiation purposes.

[0057] In the present case, the first covering layer 14a is a prepreg connected to the core 12, presently by aggregation in the usual manner. The fibrous constituents 16 are therefore prepregs in this circumstance. Said constituents 16 contain fibers 18 mentioned, in the figure, only symbolically and by way of example.

[0058] The flattened face 8a is lined with the first covering layer 14a, i.e. respectively connected or aggregated, in such a way that only a lining zone 20 (surface section of said flattened face 8a consisting of several parts, in the present case) is covered by the first layer 14a. A free zone 22 (similarly a surface section of the flattened face 8a comprising several parts, in the present case) is, consequently, not covered by said first layer 14a. The first flattened face 8a is also not lined with an additional layer or any other elements, so that the core 12 is accessible in said free zone 22, at this flattened face 8a, from a space 24 surrounding the component 2 of the sandwich type.

[0059] As a result, the filling zone 20 is materialized by all the surface sections of the flattened face 8a which are covered by all the fibrous constituents 16. The free zone 22 represents the remaining surface sections of said flattened face 8a.

[0060] Some of the fibrous constituents 16, for example the constituents 16b, 16c and 16g in the case under consideration, comprise exclusively unidirectionally oriented fibers 18 and are therefore presented as “UD prepregs”. Others of said fibrous constituents 16, such as the constituents 16a, 16d, 16e and 16f for example, on the other hand comprise interlaced fibers 18 and are therefore presented as woven fibrous constituents or as woven prepregs.

[0061] Some of these fibrous constituents 16 with intersecting fibers 18, for example the constituents 16e and 16f in the present case, are arranged on a respective edge 30 of the sandwich-type component 2, or of the core 12.

[0062] The sandwich-type component 2 also comprises mechanical coupling elements 32 and, in this case, a retaining member dedicated to fixing said component in the eVTOL. Some of the fibrous constituents 16 with intersecting fibers 18, for example the constituent 16d in this case, are associated with these elements 32 by being, more precisely, located in the region of the latter which is interposed between an element 32 and the core 12, in order to increase the mechanical robustness of said component 2 at this location.

[0063] Many of the fibrous components 16 are configured into ribbons, such as, for example, components 16b, 16c, 16e, 16f and 16g in the case under consideration. These components 16, configured into ribbons, are arranged in each case in the form of a crisscross assembly 34 on the core 12 or on the flattened face 8a, or else said crisscross assembly is respectively embodied by said components 16 configured into ribbons.

[0064] [Fig.l] illustrates, as a crisscross assembly 34, a unidirectional configuration established by strips and placed in accordance with the load. On the rear face 10, the marginal region (edge 30) of the component is reinforced by a woven prepreg (fibrous component 16e or 16f, for example).

[0065] [Fig. 2] shows the component 2 of the sandwich type of [Fig. 1], however, considered from the other direction of observation, namely a flattened face 8b of the core 12. In this case, however, said core 12 or said flattened face 8b is respectively covered by a second covering layer 26. Said face 8b is therefore lined with said second layer 26, respectively in its entirety or over the entire surface. Consequently, the entire surface of the flattened face 8b forms the lining zone 20 dedicated to the second covering layer 26. A free zone 22 is non-existent concerning said second layer 26.

[0066] This face of the sandwich-type component 2, respectively the flattened face 8b, then appears as a visible face 40, that is to say that, when said component 2 is integrated into the eVTOL-type aircraft in accordance with its intended purpose, said face can be seen by passengers from a non-illustrated passenger compartment of said aircraft. Passengers occupying the eVTOL can, in this way, point their gaze at this visible face 40, which face 40 is thus covered by the second covering layer 26 over the entire surface area, in order to provide an optically attractive appearance of said sandwich-type component 2.

[0067] Therefore, the second covering layer 26 is a layer of flattened prepreg which is also stretched around corners and edges as is known in the art for internal cladding structural parts.

[0068] [Fig.2] also shows a diagram of the progress of a manufacturing process for component 2 of the sandwich type: during a step SI of said process, the core 12 is primed. During a successive step S2, at least one of the flattened faces 8a and 8b, the face 8a in this case, is provided with the first covering layer 14a in such a way that the core 12 remains accessible from the surrounding space 24, in the free zone 22, at the level of this flattened face 8a.

[0069] [Fig. 3] is a symbolized cross-section of the sandwich-type component 2, along the line III-III drawn in Figures 1 and 2. It can then be seen, once again, how the core 12 is only partially lined with the first covering layer 14a on its first flattened face 8a, which gives rise to the lining zone 20, as well as to the free zone 22. At the flattened face 8b, on the other hand, said core 12 is lined with the second covering layer 26 integrally or, respectively, over the entire surface.

[0070] [Fig. 3] represents, in this respect, a structural organization comprising a 6 mm cell and UD strips: the second covering layer 26 is a prepreg (lattice structure), the core 12 being a 6 mm thick structural honeycomb part.

[0071] [Fig.4] is a cross-section of an alternative embodiment of a component 2 of the sandwich type which corresponds, concerning the core 12 and the first flattened face 8a, as well as the filling of these by the first covering layer 14a, to the first example of embodiment in accordance with figures 1 to 3.

[0072] In this case, however, a first covering layer 14b corresponding to the first covering layer 14a is, first of all, also deposited on the second flattened face 8b. In this case, by means of an adhesive film 28, the second covering layer 26 is then initially deposited as the extreme upper layer, so that it completely covers the surface of both the core 12 and said first covering layer 14b.

[0073] [Fig.4] thus depicts a structural organization with a 6 mm cell and a thin layer of foam: said structural organization corresponds to that of [Fig. 3], the second covering layer 26 however being made up of a component or structural part 42 made of foam. This is necessary given that the core in the form of the honeycomb structural part cannot be decorated (open cells).

[0074] [Fig. 5] illustrates another modified embodiment of a sandwich-type component 2. The latter does not have any visible face 40 in the state integrated into the eVTOL in accordance with its intended purpose, and therefore cannot be seen by passengers. This is why its visual appearance is not significant, which is why it does not contain any second covering layer 26. In this case, only a first covering layer 14a or 14b in accordance with the preceding embodiments is deposited, each time, on the two flattened faces 8a and 8b of the core 12. Furthermore, unlike the above developments, said core 12 is not a honeycomb core, but a foam core, which has a closed surface and can therefore already be decorated in itself.

[0075] [Fig. 6] shows a rear face 10 of another variant of a sandwich-type component 2 which corresponds, in principle, to the embodiment according to FIGS. 1 to 3, in which case, nevertheless, another structural organization of the first covering layer 14a is established by variants of fibrous constituents 16. As a result, the interlaced assembly 34, or even its arrangement, is then respectively selected in variant mode.

[0076] Said interlaced assembly 34 is presented, in this case, as a unidirectional configuration established by strips and put in place in the manner of a network. On said rear face 10, the marginal region (edge 30) of the component is reinforced by a woven prepreg. Other regular configurations (rectangles, squares, etc.) are also possible in a general manner (not illustrated).

[0077] In all the embodiments, both the first covering layers 14a and 14b and the second covering layers 26 are each of single-layer design. This means that for each of said first layers 14a and 14b and for each of said second layers 26, only one layer of fibrous constituents 16 is respectively deposited on the core 12, with the exception, here, of crossings 36 or bifurcations 38 of fibrous constituents 16 which are mentioned, by way of example, in said assembly 34. Although two or three fibrous constituents 16 are also placed in localized superposition, if necessary, this only concerns small longitudinal segments of the respective constituents 16. Therefore, a "single-layer" design is however mentioned in the present case.

[0078] Figures 3, 4 and 5 should be perceived as schematic diagrams in the form of an exploded / rectified illustration. Concretely, the first covering layers 14a and 14b considered are produced in the outcrop of the core 12, which is respectively indicated by dotted lines or by arrows, in [Fig. 5], for two constituents within the fibrous constituents 16. Said core 12 is subjected to slight localized compression at the location of a constituent 16, so that said constituent 16 sinks, or is respectively imprinted (direction of the arrows) in said core at the manufacturing stage.

[0079] It is understood that numerous modifications may be made to the invention as described and shown, without departing from the scope of the content disclosed herein.

[0080] The elements, objects, indications and information illustrated in the figures are referenced as follows:

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[0103] 2: sandwich type component 4: aircraft window 6: structural cladding part 8a, 8b: flattened faces of the core 10: posterior face of the nucleus 12: core 14a, 14b: first layer of component covering 16a, 16b, 16c, ...: fibrous constituents 18 fibers 20 filling area of the flattened face 22 free area of the flattened face 24 surrounding space 26 second covering layer of the component 28 adhesive film 30 respective edge of the component or core 32 mechanical coupling elements 34 interlocking assembly 36 crossings of the covering layers 38 bifurcations of the covering layers 40 visible face of the component 42 structural foam part SI, S2: steps of the manufacturing process Of course, the invention is not limited to the embodiments described and shown in the attached drawings. Modifications remain possible, particularly from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. A sandwich-type component or building element (2) comprising - a core (12) provided with two flattened faces (8a, 8b) facing away from each other - and at least one first covering layer (14a, 14b) which is connected to said core (12), ensures the mechanical stabilization of said component (2) and is provided with at least one fibrous constituent (16) containing fibers (18), a component or element (2) characterized in that - at least one of the flattened faces (8a, 8b) is lined with the first covering layer (14a, 14b) - in such a way that only a filling zone (20) of this flattened face (8a, 8b) is covered by said first layer (14a, 14b), thus leaving a free, uncovered zone (22) of said flattened face (8a, 8b), - which flattened face (8a, 8b) is not lined with any other layer, so that the core (12) is accessible in said free zone (22), at the level of this flattened face (8a, 8b),from a surrounding space (24).,

2. Component (2) of the sandwich type according to claim 1, characterized in that the filling zone (20) occupies at least 10% and, at most, 50% of the total surface area of the flattened face (8a, 8b) considered.

3. Sandwich-type component (2) according to any one of the preceding claims, characterized in that at least one of the fibrous constituents (16) comprises fibers (18) with exclusively unidirectional orientation.

4. Sandwich-type component (2) according to any one of the preceding claims, characterized in that at least one of the fibrous constituents (16) comprises interlaced fibers (18).

5. Sandwich-type component (2) according to claim 4, characterized in that at least one of the fibrous constituents (16) is arranged, with intersecting fibers (18), on an edge (30) of the flattened face (8a, 8b) in question.

6. Sandwich-type component (2) according to any one of claims 4 to 5, characterized in that said component (2) contains at least one mechanical coupling element (32) mechanically connected, rigidly, to the remaining part of said component (2), and at least one of the fibrous constituents (16) with intersecting fibers (18) is associated with said coupling element (32).

7. Sandwich-type component (2) according to any one of the preceding claims, characterized in that at least one of the fibrous constituents (16) is configured as a ribbon.

8. Sandwich-type component (2) according to claim 7, characterized in that at least a part of at least one of the first covering layers (14a, 14b) is designed as fibrous components (16) configured as ribbons and arranged, in the form of a crisscross assembly (34), on the flattened face (8a, 8b) in question.

9. Sandwich-type component (2) according to any one of the preceding claims, characterized in that at least a part of at least one of the first covering layers (14a, 14b) is of single-layer design with respect to the fibrous constituents (16).

10. Sandwich-type component (2) according to any one of the preceding claims, characterized in that at least a part of at least one of the first covering layers (14a, 14b) is produced in the outcrop of the core (12).

11. Component (2) of the sandwich type according to any one of the preceding claims, characterized in that at least one of the flattened faces (8a, 8b) is provided with a second covering layer (26).

12. Sandwich-type component (2) according to claim 11, characterized in that at least one of the flattened faces (8a, 8b) is covered by the second covering layer (26) over the entire surface.

13. Component (2) of the sandwich type according to claim 12, characterized in that one of the flattened faces (8a, 8b), covered by the second covering layer (26) over the entire surface, is a visible face (40) of said component (2) when said component (2) is in a state of assembly conforming to its intended purpose.

14. Sandwich-type component (2) according to any one of claims 11 to 13, characterized in that at least one of the second covering layers (26) contains a foam component or structural part (42).

15. Method for manufacturing a component or construction element (2) of the sandwich type according to any one of claims 1 to 14, method characterized in that - the core (12) is primed, - at least one of the flattened faces (8a, 8b) being provided with the first covering layer (14a, 14b) in such a way that said core (12) remains accessible in the free zone (22), at the level of this flattened face (8a, 8b), from the surrounding space (24).

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