METAL AND COMPOSITE TUBE INCLUDING SHOCK-ABSORBING FOAM

Abstract

The invention relates to a metallic and composite tube (4) comprising a first tube (6) made of metallic material, a second tube made of composite material, and a damping stack (8). The damping stack (8) is located inside the first tube (6) and the second tube. The damping stack (8) comprises at least a first layer (80) of damping foam and a second layer (80) of damping foam, which are separated from each other by a transverse wall (84) made of composite material. (Figure 1)

Description

Title of the invention: METAL AND COMPOSITE TUBE COMPRISING SHOCK ABSORBING FOAM Technical field of the invention

[0001] The invention relates to the field of manufacturing structural tubes, particularly for vehicles. More specifically, it concerns a metal and composite tube. In particular, the metal and composite tube forms part of a vehicle chassis and is designed to protect the occupants of the vehicle from injury in the event of an accident. The vehicle is, for example, a light aircraft such as a private plane or an ultralight motorized aircraft, also known as an "ULM". Prior art

[0002] The chassis of current light land or air vehicles are generally metallic. These metallic materials are often heavy. For legal and environmental reasons, the mass of vehicles tends to decrease, primarily to limit the pollution generated by these vehicles.

[0003] Materials lighter than metals and their alloys are being developed and used. Composite materials are known for their low mass and mechanical strength. However, composite materials are rarely used in the chassis of motorized land or air vehicles due to their low maximum plastic deformation and the risk of sudden breakage, generating fragments that could be dangerous to people nearby in the event of an accident.

[0004] The safety requirements for persons on board the vehicle also tend to become more stringent, particularly to ensure that the vehicle effectively protects these persons in the event of an accident. Vehicle safety requirements are also difficult to reconcile with vehicle mass reduction requirements, which tend to reduce the maximum amount of energy the vehicle can absorb in an accident without injuring the persons on board.

[0005] Metallic and composite tubes have recently been developed for automotive and aeronautical use, as illustrated for example by the IEE Access publication, "Crashworthiness Analyses and Design of Metal / CFRP hybrid structures under lateral loading", by Guohua Zhu, Xuan Zhao, Peilong Shi and Qiang Yu, which was published on May 30, 2019. These metallic and composite tubes have made it possible to increase the mechanical strength of tubes, while limiting the mass and size of the tubes.

[0006] There is a need to further increase the mechanical strength of a tube, all by limiting the mass and size of the tube. In particular, there is a need to improve the safety of a driver, pilot, and / or passengers inside a vehicle in the event of an accident, while limiting the mass and size of the vehicle. Description of the invention

[0007] The invention aims to remedy all or part of the disadvantages of the prior art mentioned above.

[0008] In this regard, the invention relates to a metallic and composite tube, particularly for a land and / or air vehicle. The metallic and composite tube comprises a first tube made of metallic material and a second tube made of composite material.

[0009] According to the invention, the metallic and composite tube comprises a damping stack inside the first tube and the second tube. The damping stack comprises at least a first layer of damping foam and a second layer of damping foam which are separated from each other by a transverse wall of composite material.

[0010] Thanks to the metal and composite tube according to the invention, the mechanical strength of a tube is increased, while limiting the mass and size of the tube. The safety of a pilot, driver, and / or passengers is notably improved, while also limiting the mass and size of a vehicle incorporating the metal and composite tube. The manufacture of the metal and composite tube is relatively straightforward. In particular, the shock-absorbing stack is relatively easy to produce.

[0011] In particular, the safety of persons inside the vehicle is improved, since the metal and composite tube absorbs a large amount of energy during a vehicle accident, while deforming in a controlled manner, thus preventing injury to persons during the tube's deformation. The metal material of the first tube, the composite material of the second tube and the damping stack, and the damping foam provide a maximum energy absorption that is greater than the sum of the maximum energy absorbed by the metal material, by each composite material, and by each damping foam, while controlling the deformation of the metal and composite tube.

[0012] The metallic material of the first tube protects the damping foam and the composite material of the second tube and / or the damping stack, in particular from radiation, mechanical shocks, and humidity. The metallic material deforms gradually by plastically deforming until it breaks. By deforming more gradually, the metallic material helps to control the deformation of the composite material and the damping foam. The risk of a sudden break in the composite material is limited, which could, for example, lead to injuring people in the vehicle. The risks of damage to the foam are limited, notably by promoting elastic deformation of the foam.

[0013] The composite material exhibits high resistance to deformation and impact, particularly compared to metallic materials. Cracks in the composite material are accompanied by plastic deformation in the metallic material. The composite material allows for a reduction in the mass and size of the tubes.

[0014] The shock-absorbing foam is configured to deform elastically by absorbing impact energy. It absorbs energy quickly and easily in the event of an accident. The shock-absorbing foam is particularly effective at absorbing impact energy of limited intensity. The maximum deformation amplitude of the foam is reduced by each transverse wall and by the second tube, thus limiting damage to the foam, such as tearing. The foam allows for efficient energy absorption while minimizing the mass and size of the tubes.

[0015] According to one embodiment, the first tube encloses the second tube while being located outside the second tube. The second tube encloses the damping stack while being located outside the damping stack.

[0016] According to another embodiment, the metal and composite tube is cylindrical with a circular cross-section. The first tube is cylindrical with a circular cross-section. The second tube is cylindrical with a circular cross-section. The damping stack is cylindrical with a circular cross-section.

[0017] According to one embodiment, the damping foam comprises a closed-cell solid foam. Preferably, the damping foam is a cross-linked polymer foam suitable for a land and / or air vehicle.

[0018] According to another embodiment, the composite material of the second tube and / or the transverse wall comprises a matrix and reinforcing fibers. The matrix comprises at least one resin selected from at least one polyepoxide, one polyester, and one polyetherketone. The reinforcing fibers comprise at least one element selected from carbon fibers, glass fibers, and aramid fibers.

[0019] According to a particular embodiment, each transverse wall is in the same composite material as the composite material of the second tube.

[0020] According to another embodiment, the composite material comprises a polyepoxide and carbon fibers.

[0021] According to one embodiment, the first tube made of metallic material is manufactured from a metallic material comprising aluminum and / or titanium. Preferably, the first tube is manufactured from a titanium alloy.

[0022] According to another embodiment, the damping stack comprises at least three layers of damping foam. Two consecutive layers of damping foam are separated by a transverse wall made of composite material.

[0023] According to one embodiment, the damping foam layers of the damping stack are identical in pairs.

[0024] According to another embodiment, the metal and composite tube comprises at least two damping stacks inside the first and second tubes. Each damping stack comprises at least a first layer of damping foam and a second layer of damping foam, which are separated from each other by a transverse wall of composite material.

[0025] According to one embodiment, the metal and composite tube comprises contiguous damping stacks along the longitudinal direction of the metal and composite tube.

[0026] According to another embodiment, a layer of damping foam in one of the damping stacks is different from a layer of damping foam in another of the damping stacks.

[0027] According to one embodiment, the second tube is segmented along the longitudinal direction of the composite and mechanical tube, each segment of the second tube having a length identical to the length of one of the damping stacks along the longitudinal direction of the composite and mechanical tube.

[0028] The invention also relates to a method for manufacturing a metallic and composite tube as defined above. The manufacturing method includes a step of manufacturing the damping stack by stacking at least two layers of damping foam separated by a transverse wall of composite material. The manufacturing method includes a step of manufacturing the second tube around the damping stack. The manufacturing method includes a step of inserting the damping stack and the second tube inside the first tube.

[0029] According to one embodiment, the damping stack is made by stacking layers of damping foam which are separated by transverse walls of composite material, and by cutting the damping foam and each transverse wall to the shape of the first tube and / or the second tube.

[0030] According to another embodiment, the second tube is manufactured layer by layer around the damping stack by impregnating fiber sheets with the composite material matrix.

[0031] The invention finally relates to an aircraft comprising a tubular frame. The frame comprises a set of tubes which includes metallic and composite tubes as defined above. brief description of the figures

[0032] The present invention will be better understood upon reading the description of exemplary embodiments, with reference to the accompanying drawings in which: • [Fig. 1] is a schematic representation, partly in perspective and partly torn away, of a metallic and composite tube according to a first embodiment; • [Fig.2] is a perspective representation of a damping stack and the second tube of the metallic and composite tube according to the first embodiment; • [Fig.3] is a longitudinal cross-sectional representation of a damping stack and the second tube of the metallic and composite tube according to the first embodiment; • Fig. 4 illustrates the manufacturing process of the metal and composite tube according to the first embodiment; • Figures 5a and 5b illustrate process steps for manufacturing a damping stack of the metallic and composite tube according to the first embodiment; • [Fig.6] is a perspective representation of an aircraft chassis comprising a set of metal and composite tubes according to the first embodiment; • Figure 7 is a side view representation of an aircraft comprising a chassis formed by an assembly of metal and composite tubes according to the first embodiment;

[0033] For clarity, identical or similar elements are identified by identical reference signs on the drawings. DETAILED description of a method of implementation

[0034] Figure 1 represents a metallic and composite tube 4, for example, for a land and / or air vehicle 1 such as a light aircraft like the one shown in Figure 10. The metallic and composite tube 4 comprises a first tube 6 made of metallic material, a second tube 7 made of composite material, and at least one damping stack 8. More precisely, the metallic and composite tube 4 comprises a plurality of damping stacks 8, 81, 83, 85. The metallic and composite tube 4 is, in particular, a structural tube. In particular, the metallic and composite tubes 4 serve to mechanically protect persons inside an assembly of these metallic and composite tubes 4, while limiting the mass and size of the assembly of metallic and composite tubes 4.

[0035] In this document, and unless otherwise specified, an axial direction is a direction parallel to the longitudinal direction XX of the metallic and composite tube 4. A radial direction is a direction locally perpendicular to the axial direction. An orthoradial direction is a direction locally perpendicular to both the axial and radial directions. A plane A transverse plane is a plane that is orthogonal to the longitudinal direction XX of the metallic and composite tube 4. A transverse plane is formed by a radial direction and an ortho-radial direction.

[0036] In the embodiment shown, the metal and composite tube 4 is cylindrical with a circular cross-section about the longitudinal direction XX of the metal and composite tube 4. The first tube 6 is cylindrical with a circular cross-section centered about the longitudinal direction XX of the metal and composite tube 4. The second tube 7 is cylindrical with a circular cross-section centered about the longitudinal direction XX of the metal and composite tube 4. Each damping stack 8 is cylindrical with a circular cross-section centered about the longitudinal direction XX of the metal and composite tube 4.

[0037] The first tube 6 is made of a metallic material comprising steel, aluminum, and / or titanium. The first tube 6 encloses the second tube 7, which is made of composite material, by being located on the outside of the second tube 7. The first tube 6 radially delimits the metallic and composite tube 4 outwards.

[0038] When vehicle 1 is a motorized road vehicle, the metallic material includes, for example, steel. When vehicle 1 is an aircraft, the metallic material is lighter and includes, for example, aluminum or titanium.

[0039] In each of the embodiments shown, the metallic material is a titanium alloy. The titanium alloy is, for example, a Grade 9 TiAL3V2.5 titanium alloy widely used in racing bicycle frames and aeronautical structures, manufactured by the company STAINLESS, or any other titanium alloy that offers a good compromise between mechanical strength and the density of the metallic material.

[0040] The second tube 7 is made of composite material. The second tube 7 encloses the damping stack 8 by being located outside the damping stack 8. The second tube 7 is located radially between the damping stack 8 and the first tube 6. The second tube 7 is preferably of substantially identical shape to that of the first tube 6, to facilitate mechanical contact between the second tube 7 and the first tube 6.

[0041] The second tube 7 is segmented along the longitudinal direction XX of the composite and mechanical tube. Each segment of the second tube 7 radially encloses one of the damping stacks 8, 81, 83, 85. In particular, each segment of tube 7 has a length identical to the length of one of the damping stacks 8, 81, 83, 85 along the longitudinal direction XX of the composite and mechanical tube.

[0042] Each second tube segment 7 and each damping stack 8, 81, 83, 85 forms a damping assembly which is called a "damping cartridge 9" in the embodiment shown, due in particular to its cylindrical shape. The damping cartridge 9 is radially delimited outwards by the second tube segment 7 which adheres to the damping stack 8. The damping cartridge 9 is axially delimited by transverse walls 84 of the damping stack 8.

[0043] The composite material of the second tube 7 and / or of each transverse wall 84 of Each damping stack 8 comprises a matrix and reinforcing fibers. The matrix comprises at least one resin selected from at least one polyepoxide, one polyester, and one polyetherketone. The reinforcing fibers comprise at least one element selected from carbon fibers, glass fibers, and aramid fibers. Aramid fibers are also known by the trade name "Kevlar."

[0044] In the embodiment shown, the composite material comprises a po lyepoxide and carbon fibers. The lyepoxide is, for example, the product known under the trade name "SR 1500" from the company Sicomin. The carbon fibers are, for example, fibers known as "C193 Carbon Twill 193 g / m² 3K" from the company Sicomin. In the embodiment shown, the second tube 7 and each transverse wall 84 are made of the same composite material.

[0045] The damping stacks 8, 81, 83, 85 are contiguous along the longitudinal direction XX of the metallic and composite tube 4. In other words, two consecutive damping stacks 81, 83 and 83, 85 along the longitudinal direction of the metallic and composite tube 4 are in direct mechanical contact with each other. The damping stacks 8, 81, 83, 85 extend, in particular, along the entire axial length of the metallic and composite tube 4. The number of damping stacks 8 inside the metallic tube 4 depends, for example, on the axial length of the metallic and composite tube 4.

[0046] Each damping stack 8 has an outer contour that is identical to the inner contour of the second tube 7. The damping stack 8 is located inside the second tube 7, in radial contact with it. Each damping stack 8 is formed by alternating layers of damping foam and composite material. Each damping stack 8 comprises layers 80 of damping foam and transverse walls 84 between the layers 80 of damping foam. The damping stack 8 serves to efficiently absorb energy in the event of impacts, while limiting the mass and size of the metallic and composite tube 4.

[0047] The damping foam layers 80 are arranged along the longitudinal direction of the damping stack, which is also the longitudinal direction XX of the metal and composite tube. Two consecutive damping foam layers 80 are separated by a transverse wall 84. The transverse walls 84 play a role This mechanical design is important because it reduces the risk of buckling of the second tube 7, and therefore of the first tube 6, during an impact with lateral stresses. Each layer 80 of damping foam is formed by a block of damping foam. The layers 80 of damping foam successively absorb energy in the event of impacts on the metallic and composite tube 4.

[0048] The number of layers 80 in each damping stack 8 is variable. Each transverse wall 84 is flat and extends transversely. Each transverse wall 84 is made of composite material. Each transverse wall 84 serves to separate two consecutive layers 80 of damping foam or to define the transverse boundary of the damping stack 8. The transverse walls 84 limit the mechanical deformations of the layers 80 of damping foam that they define axially. The transverse walls 84 transmit the energy of an impact from one layer 80 of damping foam to the other in the axial direction.

[0049] In the embodiment shown, each damping stack 8 comprises four layers 80 of damping foam. The different layers 80 of damping foam are identical to each other. In particular, the damping foam of the different layers 80 of damping foam is identical, and the thicknesses e of each layer 80 are equal in pairs. The transverse walls 84 are identical in pairs.

[0050] The damping foam in each layer 80 of damping foam is a solid, closed-cell foam. The damping foam is a cross-linked polymer foam suitable for land and / or air vehicles. The density of the damping foam varies from one damping stack 8 to another. The damping foam in each layer 80 of damping foam serves to absorb energy in the event of impacts against the metallic and composite tube 4, by deforming elastically.

[0051] In the embodiment shown, the damping foam is, for example, a cross-linked polymer foam known under the trade name "Airex," with densities of 60 kg / m³, 80 kg / m³, and 100 kg / m³. It is marketed by the company Sicomin. The foam can also be a metallic foam made of aluminum or titanium alloy, such as the range of foams produced by the company GRIM NéoLATTICE. The foam can also be a LATTICE structure produced by 3D printing in metal or plastic.

[0052] In the illustrated embodiment of the metallic and composite tube 4, the damping stacks 81, 83, 85 are different. The transverse walls 84 of each of the damping stacks 8 are identical. The layers 80 of the damping stacks 81, 83, 85 are different, with a damping foam density that increases for the layers 80 of the damping stacks 81, 83, 85 towards a space for people such as a vehicle passenger compartment 1.

[0053] Fig. 4 illustrates the manufacturing process 100 of the metallic and composite tube 4. Process 100 includes a manufacturing step 101 of the first tube 6, a manufacturing step 200 of the damping stack 8, a manufacturing step 300 of the second tube 7, and a manufacturing step 106 of inserting the damping stack 8 and the second tube 7 inside the first tube 6. The order of manufacturing steps 101, 200, and 300 may vary. The insertion step 106 of the damping stack 8 and the second tube 7 inside the first tube 6 occurs after manufacturing steps 101, 200, and 300.

[0054] The first tube 6 is, for example, a commercially available tube. Step 101 of manufacturing the first tube is generally a preliminary step which is carried out by persons other than those who carry out the other steps of the manufacturing process 100.

[0055] Figures 5a and 5b illustrate step 200 of manufacturing each damping stack 8. Each damping stack 8 is formed by an alternating stack 201 of blocks 82 of damping foam and sheets 86 of fibers impregnated with composite material, forming an initial stack 85. The initial stack 85, after polymerization and post-curing in an oven, is then cut to the shape of the first tube 6 and the second tube 7. During the cutting step 203 of the initial stack 85, all the blocks 82 of damping foam and sheets 86 of fibers impregnated with composite material are cut, preferably in one go. The initial stack 85 is for example heated and pressed, to promote polymerization and drying of the composite material which will form the transverse walls 84, preferably before the cutting step 203. The initial stack 85 can also be placed under vacuum.

[0056] Figure 5b illustrates step 300 of manufacturing the second tube 7. The second tube 7 is manufactured layer by layer around the damping stack 8 by impregnating fibers with the matrix of the composite material. The fibers of the composite material of the second tube 7 are, for example, in the form of sheets which are wound one after the other around the damping stack 8, after the fibers have been impregnated 203 by the matrix. The composite material of the second tube 7 is, for example, mechanically pressed against the damping stack 8 before steaming and curing. The assembly of the second tube 7 and the damping stack 8 can be formed and layered under vacuum before steaming and curing. Heating the composite material particularly promotes the polymerization and drying of the matrix of the composite material, especially when the matrix is ​​a thermosetting resin such as a polyepoxide.

[0057] During step 106 of inserting the damping stack 8 and the second tube 7 inside the first tube 6, the damping stack 8 and the second tube 7 are, for example, forced inside the first tube 6. The damping stack 8 and the second tube 7 are, for example, rigidly attached to the first tube 6, being compressed inside the first tube 6.

[0058] Alternatively, during step 106 of inserting the damping stack 8 and the second tube 7 inside the first tube 6, the damping stack 8 and the second tube 7 are movable relative to the first tube 6, for example, for sliding along the longitudinal direction XX of the metallic and composite tube 4. The damping cartridge 9 formed by the damping stack 8 and the second tube 7 can thus be easily replaced, for example, when the damping foam is damaged.

[0059] Figure 9 shows a chassis 2 for a land or air vehicle 1, which is a tubular chassis 2 comprising metallic and composite tubes 4. The chassis 2 includes vertices 20 and a tube assembly comprising the metallic and composite tubes 4. The chassis 2 serves to protect the persons inside the aircraft in the event of an accident, passively, i.e., without control or intervention from a pilot. The vertices 20 rigidly connect the metallic and composite tubes 4 to each other. The metallic and composite tubes 4 that are furthest from the passenger compartment of the vehicle 1 are configured to deform more rapidly in order to absorb as much energy as possible, far enough away from the persons inside the passenger compartment, in the event of an accident. The metallic and composite tubes 4 that are closest to the passenger compartment are those with the highest mechanical resistance, in order to protect the persons inside the passenger compartment.

[0060] In particular, the metallic and composite tubes 4 may include shock-absorbing foam densities which vary according to the longitudinal direction XX of the metallic and composite tubes 4, in order to best absorb shocks while protecting people in the vehicle.

[0061] Figure 10 represents a light aircraft 1 such as a touring aircraft or an ultralight motorized aircraft, which is known as an ultralight. The aircraft 1 comprises a frame 2, wings 3, wheels 5 and a propeller 6. The metallic and composite tubes 4 of the frame 2 are particularly useful in the case of a light aircraft 1 in which the safety of persons on board is likely to be significantly improved.

[0062] Thanks to the metallic and composite tube 4 according to the invention, the mechanical strength of the tube 4 is very high, while limiting its mass and size. The safety of a pilot, driver, and / or passengers is improved, while limiting the mass and size of a vehicle 1 comprising the metallic and composite tube 4. The manufacture of the metallic and composite tube 4 is relatively easy. In particular, the damping stack 8 is relatively easy to manufacture.

[0063] The safety of persons inside the vehicle 1 is improved, since the metallic and composite tube 4 absorbs a large amount of energy during an accident. Vehicle 1, while deforming in a controlled manner to avoid injuring people during the deformation of tube 4. The metallic material of the first tube 6, the composite material of the second tube 7 and the damping stack 8, and the damping foam, provide a maximum energy absorption that is greater than the sum of the maximum energy absorbed by the metallic material, by each composite material, and by each damping foam, while controlling the deformation of the metallic and composite tube 4.

[0064] The metallic material of the first tube 6 protects the damping foam and the composite material of the second tube 7 and / or the damping stack 8, in particular from radiation, mechanical shocks, and humidity. By deforming more gradually, the metallic material helps control the deformation of the composite material and the damping foam, limiting the risk of a sudden break in the composite material that could, for example, injure people in the vehicle 1. The risks of damage to the foam are limited, notably by promoting elastic deformation of the foam.

[0065] The composite material exhibits high resistance to deformation and impact, particularly compared to metallic materials. The appearance of cracks in the composite material is accompanied by plastic deformation of the metallic material. The number of hazardous fragments formed by deterioration of the composite material is greatly reduced. The composite material reduces the mass and size of the tubes compared to tubes of the same dimensions made solely of metallic material.

[0066] The shock-absorbing foam is configured to deform elastically. It quickly and easily absorbs energy in the event of an accident. In particular, the shock-absorbing foam absorbs the energy of impacts of limited intensity. The maximum deformation amplitude of the foam is reduced by each transverse wall and by the second tube, which limits damage to the foam, such as tearing. The foam allows for efficient energy absorption while limiting the mass and size of the four metal and composite tubes.

[0067] Each damping cartridge 9 is capable of being replaced independently of the other damping cartridges 9 and independently of the first tube 6. The replacement of the damping cartridges 9 takes place for example due to the aging of the damping foam of the damping stacks 8.

[0068] Of course, various modifications can be made by a person skilled in the art to the invention which has just been described without going out of the scope of the disclosure of the invention.

[0069] Alternatively, the second tube 7 encloses the first tube 6, being located outside the first tube 6. In this case, the damping stack 8 is inside of the first tube 6.

[0070] Alternatively, the second tube 7 is axially monobloc.

[0071] Alternatively, the cross-section of the first tube 6, the second tube 7 and / or of The damping stack 8 is polygonal. For example, the first tube 6, the second tube 7, and the damping stack 8 have a square cross-section.

[0072] Alternatively, the metallic and composite tube 4 comprises a single damping stack 8 which has, for example, the same axial length as the axial length of the metallic and composite tube 4.

[0073] Alternatively, at least two consecutive damping stacks 8 along the longitudinal direction XX of the metallic and composite tube 4 are spaced and axially separated from each other. The metallic and composite tube 4 then comprises at least one longitudinal section without a damping stack 8.

[0074] Alternatively, the composite material of the second tube 7 is distinct from that of at least one transverse wall 84 of the damping stack 8. Alternatively, the thickness of each transverse wall 84 is variable depending on the desired mechanical characteristics and especially on the position of the tube in the chassis 2.

[0075] Alternatively, the 80 layers of damping foam in different 8 damping stacks are identical. Alternatively, two separate 80 layers of damping foam in a single 8 damping stack are different. The foam thickness may also vary between two 80 layers.

[0076] Alternatively, the thickness of at least two distinct floors 80 is different.

[0077] Alternatively, the cushioning foam and the composite material are cut before being stacked.

[0078] Alternatively, the second tube 7 is manufactured layer by layer around a central insert by impregnating fibers with the matrix of the composite material. The fibers are, for example, in the form of sheets that are wound one after the other around a central insert, after the fibers have been impregnated by the matrix. The central insert is inflated with a pressurized fluid, for example air, to press the composite material of the second tube 7 against the first tube 6. The composite material is, for example, heated when it is pressed by the central insert against the first tube 6. The insert is then depressurized and removed from the second tube 7, after the composite material of the second tube 7 has been bonded to the first tube 6.

[0079] Alternatively, the metallic and composite tube 4 is a structural tube for a use other than a land or air vehicle 1, for example for a tent peg.

[0080] Alternatively, vehicle 1 is a motorized land vehicle, such as a car. Alternatively, vehicle 1 is a non-motorized vehicle, such as a bicycle.

Claims

Demands

1. Metallic and composite tube (4), in particular for a land and / or air vehicle (1), comprising a first tube (6) of metallic material, a second tube (7) of composite material, characterized in that the metallic and composite tube (4) comprises a damping stack (8) inside the first tube (6) and the second tube (7), the damping stack (8) comprising at least a first stage (80) of damping foam and a second stage (80) of damping foam which are separated from each other by a transverse wall (84) of composite material.

2. Metallic and composite tube (4) according to any one of the preceding claims, wherein the first tube (6) encloses the second tube (7) by being located outside the second tube (7), the second tube (7) encloses the damping stack (8) by being located outside the damping stack (8).

3. Metallic and composite tube (4) according to any one of the preceding claims, wherein the metallic and composite tube (4) is cylindrical with a circular cross-section, the first tube (6) is cylindrical with a circular cross-section, the second tube (7) is cylindrical with a circular cross-section, the damping stack (8) is cylindrical with a circular cross-section.

4. Metallic and composite tube (4) according to any one of the preceding claims, wherein the damping foam of each stage (80) of damping foam comprises a closed-cell solid foam, the damping foam preferably being a cross-linked polymer foam suitable for a land and / or air vehicle (1).

5. Metallic and composite tube (4) according to any one of the preceding claims, wherein the composite material of the second tube (7) and / or the transverse wall (84) comprises a matrix and reinforcing fibers, the matrix comprising at least one resin selected from at least one polyepoxide, polyester and polyetherketone, the reinforcing fibers comprising at least one element selected from carbon fibers, glass fibers and aramid fibers.

6. A metallic and composite tube (4) according to the preceding claim, wherein each transverse wall (84) is made of the same composite material as the composite material of the second tube (7), and / or wherein the composite material comprises a polyepoxide and fibers of carbon.

7. Metallic and composite tube (4) according to any one of the preceding claims, wherein the first metallic tube (6) is made of a metallic material comprising aluminum and / or titanium, preferably a titanium alloy.

8. Metallic and composite tube (4) according to any one of the preceding claims, wherein the damping stack (8) comprises at least three layers (80) of damping foam, two consecutive layers (80) of damping foam being separated by a transverse wall (84) of composite material, and / or wherein the layers (80) of damping foam of the damping stack (8) are two by two identical.

9. Metallic and composite tube (4) according to any one of the preceding claims, wherein the metallic and composite tube (4) comprises at least two damping stacks (8, 81, 83, 85) inside the first tube (6) and the second tube (7), each damping stack (8, 81, 83, 85) comprising at least a first stage (80) of damping foam and a second stage (80) of damping foam which are separated from each other by a transverse wall (84) of composite material.

10. Metallic and composite tube (4) according to the preceding claim, wherein the metallic and composite tube (4) comprises contiguous damping stacks (81, 83) along the longitudinal direction (XX) of the metallic and composite tube, and / or wherein a layer (80) of damping foam of one of the damping stacks (81) is different from a layer (80) of damping foam of another of the damping stacks (83, 85).

11. Metallic and composite tube (4) according to any one of the preceding claims 9 and 10, wherein the second tube (7) is segmented along the longitudinal direction (XX) of the composite and mechanical tube, each segment of the second tube (7) having a length identical to the length of one of the damping stacks (8, 81, 83, 85) along the longitudinal direction (XX) of the composite and mechanical tube.

12. A method for manufacturing a metallic and composite tube (4) according to any one of the preceding claims, comprising a manufacturing step (200) of the damping stack (8) by stacking at least two layers of damping foam separated by a transverse wall (84) in composite material, a manufacturing step (300) of the second tube (7) around the damping stack (8), an insertion step (106) of the damping stack (8) and of the second tube (7) inside the first tube (6).

13. A method for manufacturing a metallic and composite tube (4) according to the preceding claim, wherein the damping stack (8) is made by stacking layers (80) of damping foam which are separated by transverse walls (84) of composite material, and by cutting the damping foam and each transverse wall (84) to the shape of the first tube (6) and / or the second tube (7).

14. Method of manufacturing a metallic and composite tube (4) according to any one of the preceding claims 12 to 13, wherein the second tube (7) is manufactured layer by layer around the damping stack by impregnating sheets of fibers with the matrix of the composite material.

15. Aircraft (1) comprising a tubular frame (2), the frame (2) comprising a tube assembly comprising metallic and composite tubes (4) according to any one of claims 1 to 11.

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