Thermoplastic molded part, method of manufacturing the same and pipe comprising the same

Abstract

The present invention relates to a thermoplastic molded part able to constitute a duct of an aerial or space vehicle and to a method for manufacturing such a part, as well as to a duct comprising said part. The part according to the invention has an at least partially rotationally symmetrical outer surface (2) such that the outer surface comprises a plurality of integrally molded recesses (6) connected to each other in pairs by ridges (7), and wherein: - each recess has a maximum transverse dimension D between 3-10 mm between the adjacent paired ridges, measured in a direction d perpendicular to the ridge defining each recess, and - each ridge has a top portion having a transverse width L measured in said direction d, wherein L < D.

Description

Technical Field

[0001] This invention relates to a thermoplastic molded component capable of forming a conduit in an aircraft or spacecraft, a method of manufacturing the same, and conduits comprising said component. The invention is generally applicable to any conduit substantially composed of said thermoplastic molded component, capable of resisting cracks caused by impacts from tools within the aircraft during installation or maintenance operations. Such conduits are particularly configured for conveying fluids, such as air, and advantageously capable of forming all or part of an air inlet device, such as an air inlet diffuser (or inlet air diffuser type), to provide air conditioning for the aircraft cabin both in flight and on the ground. In particular, the invention is applicable to other types of conduits conveying liquid or gaseous fluids and can be used as sites of external impact, as well as fuel lines, various fasteners, and semi-structural components. Background Technology

[0002] FR3065438A1 provides an air conditioning system intended to supply conditioned air to the cabin of an aircraft, comprising an air inlet device intended to be mounted below the belly fairing of the aircraft and including, for said purpose, a shroud connected to an opening within the fairing, and a sheath connected upstream to an air conditioning device and downstream to the shroud.

[0003] There has been an effort to replace the metal materials traditionally used in these air inlet devices with thermoplastic materials. Currently, in a known manner, thermoplastic ducts and thermoplastic matrix composites must make trade-offs between satisfactory mechanical strength (due to their reinforcement and / or strength), lightweight and / or lower density materials obtained through reduced thickness, and in applications such as air inlet devices inside aircraft (vulnerable to damage from tool impacts during duct installation or maintenance within the aircraft), impact resistance is typically achieved through deformation rather than through indestructible structures or special reinforcements.

[0004] WO 99 / 24749 A1 discloses an article, such as an aircraft pipe made of plastic, which has reduced drag during fluid flow or while passing through the article. For this purpose, the article includes an inner or outer surface having a plurality of recessed portions and / or protruding portions. This document does not address the pipe's resistance to cracking caused by impact.

[0005] The applicant recognizes that there is currently no thermoplastic duct or thermoplastic matrix composite material for air inlet devices of air conditioning systems for aircraft, wherein the duct can satisfactorily resist cracks caused by impacts from dropped tools or other impacts that may occur during installation or maintenance on the aircraft. Summary of the Invention

[0006] The object of the present invention is to provide a molded plastic matrix component capable of forming a conduit for an aircraft or spacecraft, the component having at least a partially rotationally symmetrical outer surface, and the component particularly overcomes the defects described above.

[0007] Therefore, the molded component according to the invention includes on its outer surface a plurality of integrally molded recesses connected in pairs to each other by ridges, wherein:

[0008] -Measured in a direction d perpendicular to the ridge defining each recess, each recess has a maximum lateral dimension D between 3-10 mm between adjacent pairs of ridges, and

[0009] - Each ridge has a top, the top having a lateral width L measured in the direction d, where L <D。

[0010] It will be noted that the molded part according to the invention (preferably molded by injection molding) has a parting plane (molding plane) due to the molding process. Such a molded part may have two open ends, each having a generally circular, elliptical, or polygonal end perimeter independently of the others. The term "generally" in this specification means that each related term is so defined or substantially so (e.g., mainly or generally circular, elliptical, polygonal, spherical, etc.).

[0011] It will be understood that a “recess” in this text is a recess, pit, or notch that defines a macroscopic portion that retracts from a ridge on an outer surface, thus giving the outer surface a macroscopically textured structure. Identical or different recesses can form concave portions, which may be recessed or non-recessed (e.g., with a generally circular or polygonal cross-section, such as a rectangle). Measured in a direction d perpendicular to the ridge defining each recess, the maximum lateral dimension D between the ridges thus defines the maximum lateral dimension of each recess (e.g., the diagonal or diameter of each recess, where the latter has a prismatic, cylindrical, or spherical shape) (measured perpendicular to the longitudinal axis or line of symmetry of each adjacent ridge).

[0012] In this text, "ridge" should be understood as a relief, crown, or ridge surrounding a recess, similar in manner to a microscopic protrusion on the outer surface. Identical or different ridges have corresponding apexes (farthest from the recess), which can be generally planar, linear, or curved (e.g., generally convex or concave apexes). The lateral width L of each ridge apex is also measured perpendicular to the longitudinal axis or line of symmetry of each adjacent ridge, wherein each ridge apex is narrower than each adjacent recess in said direction d (condition: L). <D)。

[0013] The Applicant states that this configuration of integrally molded recesses and ridges enables it to significantly improve the ability of the component to resist cracking due to impact compared to a component made of the same material but having an outer surface without recesses and ridges (i.e., without concavities or protrusions), as described in the subsequent examples of the present invention and in the comparative examples of molded components made of the same thermoplastic matrix composite material.

[0014] It will also be noted that this configuration according to the present invention, together with a suitable reinforcing thermoplastic material for the molded component, enables it to endow the latter with a satisfactory ability to resist bending impact.

[0015] Advantageously, each recess may have a substantially spherical recessed surface (i.e., defined by a radius of curvature R) or a substantially cylindrical recessed surface (i.e., defined by a directrix forming a bending line and by an axial generatrix for the pipe defining the length of each recess, the bending line being substantially in the form of an arc of a circle with a radius of curvature R), where preferably L < 0.5D, and for example L < 0.2D, or even L < 0.1D.

[0016] As used herein, "substantially spherical" is understood to define a recessed surface of an open spherical segment, such as a substantially hemispherical segment, and "substantially semi-cylindrical" is understood to define an open cylindrical segment, such as a substantially semi-cylindrical segment.

[0017] It will be noted that the recesses according to the present invention may have a recessed surface that includes a variable profile, such as from a parabolic profile to a rectangular profile, thereby changing the buffering and sensitivity of the ridges in response to impact, as described below.

[0018] More advantageously, the recessed surface may be defined by the radius of curvature R associated with the maximum lateral dimension D, where 0.5D < R < 2D, preferably 0.7D < R < 1.5D.

[0019] According to another general feature of the present invention, the component may have a thickness difference measured between the outer surface of the component and the radially opposite inner surface between the base of each ridge and the adjacent recess, the thickness difference being between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.3 mm.

[0020] According to another general feature of the present invention, the recesses may advantageously be identical and regularly spaced so as to form at least one circumferential row of recesses between the two open ends of the component, the said or each circumferential row extending above the perimeter of the outer surface with a repeating pitch having a value equal to D + L between two consecutive recesses of the said or each circumferential row.

[0021] It will be noted that the recesses may:

[0022] ]>- In a first embodiment of the present invention, when the recessed surface of each recess is substantially spherical, a plurality of circumferential rows are formed, and these recesses can then be aligned on the periphery of the outer surface of the component; or

[0023] - In a second embodiment of the present invention, when the recessed surface of each recess is substantially cylindrical, a single said circumferential row is formed, which is defined by a cylindrical section having a longitudinal axis along the outer surface of the component substantially having rotational symmetry.

[0024] Advantageously, the thickness difference of the component defined as above can be:

[0025] - When the pitch between the recesses is between 6 mm and 8 mm, it is between 0.8 mm and 1.3 mm, where preferably 0.7D < R < D, or

[0026] - When the pitch between the recesses is between 3 mm and 5 mm, it is between 0.3 mm and 0.7 mm, where preferably D < R < 1.3D.

[0027] According to the first embodiment in which the recesses form a plurality of spaced-apart circumferential rows on the outer surface, the recesses of each circumferential row are discontinuously formed on the outer surface in the form of golf ball dimples.

[0028] According to the second embodiment in which the recesses form a single circumferential row on the outer surface, each of the circumferential rows of recesses has a continuous substantially semi-cylindrical recessed surface on the outer surface respectively.

[0029] According to another general feature of the present invention, the component can be composed of a polymer composition based on at least one thermoplastic polymer, and the thermoplastic polymer is selected from polyamide (PA), polyphenylene sulfide (PPS), polyetherimide (PEI), poly(p-phenylene terephthalamide) (PPA), polysulfone (PPSU), polyetheretherketone (PEEK), polyaryletherketone (PAEK), and polyvinylidene fluoride (PVDF).

[0030] Preferably, the at least one thermoplastic polymer is selected from polyetheretherketone (PEEK) and polyaryletherketone (PAEK).

[0031] More preferably, the at least one thermoplastic polymer is polyetheretherketone (PEEK).

[0032] According to another general feature of the present invention, the composition may include a reinforcing member, and the reinforcing member includes:

[0033] - Reinforcing fillers distributed in the composition, such as selected from organic fillers and inorganic fillers such as carbon black and carbon nanotubes, and / or

[0034] - For example, reinforcing fibers selected from glass fiber and carbon fiber are used to form unidirectional or woven reinforcements.

[0035] The reinforcement preferably comprises discontinuous glass fibers with a mass fraction between 20% and 40%.

[0036] More preferably, the at least one thermoplastic polymer is selected from polyetheretherketone (PEEK) and polyaryletherketone (PAEK), and the reinforcement comprises discontinuous glass fiber with a mass fraction between 25% and 35%.

[0037] It will be noted that the compositions according to the invention may additionally include additives commonly used in thermoplastic compositions, such as dyes, by way of non-limiting examples.

[0038] According to another general feature of the invention, the configuration of the recess and the ridge can be configured to deform during impact, while cushioning it by crushing the ridge, so that cracks in the component are more easily detected with reduced impact energy compared to the impact energy required to form a crack on a component of the same thickness and made of the same material but without the configuration.

[0039] According to the invention, the manufacturing method for manufacturing the component as defined above involves performing a molding step by injecting a polymer composition into a mold configured to negatively form the recesses and ridges. The polymer composition includes the thermoplastic matrix and possible reinforcements, which include reinforcing fillers and / or reinforcing fibers distributed in the composition.

[0040] Preferably, the molding step includes injection molding of the composition, wherein the at least one thermoplastic polymer is selected from polyamide (PA), polyphenylene sulfide (PPS), polyetherimide (PEI), polyacetamide terephthalate (PPA), polyphenylene sulfone (PPSU), polyether ether ketone (PEEK), polyarylether ether ketone (PAEK), and polyvinylidene fluoride (PVDF), and the reinforcement comprises, for example, discontinuous glass fiber with a mass fraction between 20% and 40%.

[0041] According to the invention, the pipes for aircraft or spacecraft are configured to be installed inside the aircraft while conveying liquid or gaseous fluids therein, and the pipes include or are constituted by the molded components as defined above, which are capable of resisting cracks caused by impacts from tools during installation or maintenance operations near the pipes.

[0042] It will be noted that the pipes according to the invention can advantageously be single-layered, constructed by the molding composition, and optionally be curved and / or bent.

[0043] According to one example of the invention, the duct forms an air inlet device (e.g., a cold air inlet diffuser) for an air conditioning unit of an aircraft to supply conditioned air to at least one compartment or passenger compartment of the aircraft, the duct comprising:

[0044] - A first opening end, the first opening end having a generally circular or elliptical periphery of a conduit configured to be connected, via a tight seal, to an air conditioning unit opening in the cabin or passenger compartment in a leak-proof manner, and

[0045] - A second opening end, having a wider cross-section (e.g., a generally polygonal or rectangular perimeter) relative to the first end, is configured to connect to an air-to-air heat exchanger of the aircraft, for example, outside a cabin or passenger compartment.

[0046] Preferably, the duct of this example according to the invention has a channel cross-section that increases from a first end to a second end, and the duct is provided with means for connection to the air conditioning unit. By way of non-limiting example, the duct may be an air inlet diffuser or inlet diffuser type of a shielded duct.

[0047] In general terms, it will be understood that the pipes according to the invention can be used to transport gaseous fluids other than liquids or air, such as, for example, fuels. Attached Figure Description

[0048] Other features, advantages, and details of the invention will become clear from the following description of several exemplary embodiments of the invention, given in an exemplary and non-limiting manner with respect to the accompanying drawings, in which:

[0049] Figure 1 This is a transverse perspective view of a component according to an example of the invention, which forms an air duct of the diffuser type for an air inlet of an aircraft; the configuration of the recess and ridge is not visible.

[0050] Figure 2 This is a transverse perspective view of a component according to another example of the invention, which forms another air duct for a shield type of aircraft; the configuration of the recess and ridge is not visible.

[0051] Figure 3 yes Figure 1 A partial cross-sectional schematic diagram in plane III-III shows an example of the arrangement of the recesses on the outer surface and two adjacent ridges. The common example according to two embodiments of the invention has discontinuous and continuous recesses.

[0052] Figure 4 The diagram is a partial cross-sectional view, which more completely illustrates the two embodiments of the present invention. Figure 3Examples of lateral configurations are shown, and a first embodiment of the invention with discontinuous recesses is also illustrated. Figure 1 An example of the longitudinal configuration of the recesses and ridges in the plane IV-IV.

[0053] Figure 5 yes Figure 2 In plane VV or Figure 1 A complete schematic diagram of the cross-section of a component according to an example of the invention in plane III-III shows an example of the configuration of recesses and ridges located on the periphery of the component, common to both embodiments of the invention.

[0054] Figure 6 The photograph is a top perspective view showing an apparatus for evaluating the impact behavior of a test component and a “comparison” sample according to two embodiments of the present invention, which includes an impact device with varying impact energy.

[0055] Figure 7 This is a photograph showing, from a top perspective view, an exemplary embodiment of the first embodiment of the invention, with a configuration of discontinuous recesses and ridges.

[0056] Figure 8 The photograph shows a top view of the outer surface of a first sample A2 formed from a molded plate. The outer surface has a close arrangement of continuous recesses and ridges according to a second embodiment of the invention. The sample is constructed of the material according to the invention and is subjected to an impact energy of 3.5 J. Figure 6 The device is impacted in two situations.

[0057] Figure 9 Detailed description using perspective views Figure 8 The first sample A2 is a photograph of the continuous depressions and ridges.

[0058] Figure 10 The photograph shows a top view of the outer surface of a second sample B7 formed from a molded plate. The outer surface is provided with a more spaced-out configuration of continuous recesses and ridges according to a second embodiment of the invention. This sample is constructed of the material according to the invention and is subjected to an impact energy of 3.8 J. Figure 6 The device is impacted in two situations.

[0059] Figure 11 Detailed description using perspective views Figure 10 The photographs of the continuous depressions and ridges of the second sample B7.

[0060] Figure 12Includes three photographs, showing from a top view the outer surfaces of three “comparative” samples C4, C5, and C6 formed by a 2mm thick molded plate. The outer surfaces are planar and constructed from the same material according to the invention. The samples on the left and center were impacted in two instances with an impact energy of 2J, while the sample on the right was impacted in one instance with an impact energy of 2J.

[0061] Figure 13 Includes two photographs, showing from a top view the outer surfaces of two “contrast” samples D2 and D4 formed by a 3mm thick molded plate, the outer surfaces being planar and constructed of the same material according to the invention, wherein the samples on the left and right sides were impacted on two occasions with impact energies of 2J and 2.5J respectively.

[0062] Figure 14 Includes two photographs, showing from a top view the outer surfaces of two “contrast” samples E3 and E4 formed by a 4mm thick molded plate. The outer surfaces are planar and constructed of the same material according to the invention, wherein the samples on the left and right sides were impacted on two occasions with impact energies of 3.5J and 4J, respectively.

[0063] Figure 15 Includes three photographs, showing from a top view the outer surfaces of two “contrast” samples F3, F4, and F5 formed from a 5mm thick molded plate. The outer surfaces are planar and constructed from the same material according to the invention, wherein the samples on the left, center, and right sides are impacted with impact energies of 8J, 7J, and 7.5J, respectively. Detailed Implementation

[0064] according to Figure 1 The duct 1 shown in the example of the invention is preferably molded by injection molding and constructed of a thermoplastic composition or thermoplastic matrix composite material as defined above. The duct 1 is specifically configured to form an air inlet device connecting to a loop connected to the air conditioning unit of an aircraft, so as to regulate the cabin of the aircraft while it is in flight or on the ground (i.e., permanently, as long as the aircraft cabin is occupied). The duct 1 has an outer surface 2, which in this example includes:

[0065] - The lower end 3 of the opening has a circular periphery with a tight seal 3a, allowing it to be connected to a line or pipe of an air conditioning unit that opens inside the compartment (not shown), and

[0066] - The upper part of the opening 4 has a roughly rectangular perimeter with rounded corners, so that it is also constructed in a leak-proof manner to connect to the aircraft's air-to-air heat exchanger (which typically exchanges hot air from the engine compartment with cold outside air), which is located, for example, inside each wing of the aircraft.

[0067] The lower end 3 extends through a lower portion having a rotationally symmetric outer surface 2, having a generally curved cylindrical shape, which extends gradually and continuously through an upper portion in the form of a generally truncated pyramid having a rectangular base terminating at an upper end 4.

[0068] According to Figure 2 the example of the invention shown, the duct 1’ (such as an air inlet diffuser of the shroud duct type) is mainly different from Figure 1 the said duct 1 in that its outer surface 2’ includes, on the side opposite to its lower end 3’ (similar to Figure 1 the end 3) connected to the pipeline or duct of the air conditioning unit, an open upper end 4’ connected to the air-air heat exchanger of the aircraft, which has a generally rectangular perimeter and is provided with a planar edge of the duct having a greater margin than the upper edge of the upper end 4. The lower end 3’ also extends through a generally curved cylindrical lower portion, which extends gradually through an expanded upper portion (having a generally truncated pyramid or generally truncated cone) terminating at the upper end 4’.

[0069] The inner surfaces 5, 5’ of the ducts 1, 1’ may have a smooth geometric structure. In contrast, according to the present invention, the outer surfaces 2, 2’ include a plurality of integrally molded recesses 6, 6’ connected to each other in pairs by ridges 7, 7’ ( Figure 3-6 visible in and 8 - 11), wherein:

[0070] - Measured in a direction d perpendicular to the ridges 7, 7’ defining each recess 6, 6’, each recess has a maximum transverse dimension D between the adjacent pairs of ridges 7, 7’, and this dimension D is between 3 mm and 10 mm, and

[0071] - Each ridge 7, 7’ has a top, which has a transverse width L in the said direction d, where L < D.

[0072] In a first embodiment of the invention having discontinuous recesses (i.e., formed by a generally spherical section) and a second embodiment of the invention having continuous recesses (i.e., formed by cylindrical sections having parallel axes), which are common to Figure 3 、 4 and 5, it can be seen that each recess 6, 6’ may have the same generally hemispherical or semi-cylindrical recessed surface, the recessed surface having a bottom 6a and a radius R, where for example 0.5D < R < 2D, preferably 0.7D < R < 1.5D. Each recess 6, 6’ extends in a dimension D from a protruding edge 8 of one ridge 7, 7’ to at least one other adjacent protruding edge 8 of another ridge 7, 7’, especially in Figure 5 the exemplary example of, the ridges 7, 7’ respectively have a width D smaller than the width D of each ridge 7, 7’ of Figure 3 and 4 In other words, Figure 5 The spine is not very flat, that is, it is more flat than Figure 3 and 4 (Even sharper).

[0073] exist Figure 7 In the first embodiment of the invention, it can be seen that the recesses 6 and 6' of the pipes 1 and 1' each have practically hemispherical recessed surfaces, and the relatively pointed (i.e. not very flat) ridges 7 and 7' have tops that curve downward between two adjacent ridges 7 and 7', wherein the corresponding bottoms 6a of the recesses 6 and 6' define the radially innermost points of the pipes 1 and 1', and the joint between the ridges 7 and 7' (in Figure 7 In the example, the radial outermost point of the pipes 1, 1' is defined by four ridges 7, 7' located between pairs of perpendicular ridges, where the maximum thickness difference between the pipes 1, 1' is, for example, between 0.2 mm and 2 mm. It can be seen that these recesses 6, 6' are therefore configured to form multiple rows on the outer surfaces 2, 2' spaced apart in a manner similar to golf ball dimples.

[0074] exist Figure 8-11 Photos and Figure 3-5 In the second embodiment of the invention shown in detail, it can be seen that the recesses 6 and 6' of the pipes 1 and 1' each have substantially semi-cylindrical recessed surfaces (symmetrical longitudinal axes are formed by semi-cylindrical generatrices that are parallel to each other), and the ridges 7 and 7' can be generally flat and are also parallel to each other, each having a top that curves downward between two adjacent ridges 7 and 7', wherein the bottom 6a of the recesses 6 and 6' defines the radial innermost point of the pipes 1 and 1', and the two consecutive ridges 7 and 7' (see...) Figure 8-11 The joint between pipes 1 and 1' defines the outermost radial point of pipes 1 and 1', and the maximum thickness difference between pipes 1 and 1' is, for example, between 0.3 mm and 1.3 mm.

[0075] Tests were performed on samples having the outer surface of the present invention.

[0076] The sample being tested

[0077] The first molded parallelepiped sample is prepared by injection molding the same thermoplastic matrix polymer composition, such that one of the two main surfaces of the obtained first textured sample has, according to the first embodiment of the invention, Figure 7 The texture shown is due to the reverse-specific cavity of the first injection model, and makes each of the two main surfaces of the other first "contrast" sample smooth.

[0078] Each first smooth sample has dimensions of 950mm x 950mm x 7mm and a mass of 46.6g. Each first textured sample has macrocells, similar in type to those on golf balls, with a mass of 48.4g and a main surface of 950mm x 950mm, the thickness of which is defined by an average grid of 7mm from the macrocells.

[0079] Second-molded parallelepiped samples A, B, C, D, E, and F were prepared by injection molding of the same composition, which has a PEEK thermoplastic matrix reinforced with 30% (by weight) glass fiber (this material is trademarked). 150GL30), one of the two main surfaces of samples A and B according to the second embodiment of the present invention as follows Figure 8-11 As shown (due to the reverse specific cavity of the second injection model), and samples C, D, E, and F are "comparison" samples, having according to Figure 12-15 The smooth main surface. These second sample main surfaces AF each have a main surface size of 120mm x 80mm.

[0080] The injection molding of all samples involved the use of plunger and mold-type models, with a maximum pressure of approximately 1500 bar in the cavity of each model and a temperature between 180-200°C in each model.

[0081] More precisely, the six identical samples A1-A6 respectively have according to Figure 8-9 The textured main surface is repeated with shortened periods (i.e., high frequency) semi-cylindrical recesses with symmetrical longitudinal axes parallel to each other, and each sample A1-A6 has the characteristics described in detail in Table 1 below.

[0082] [Table 1]

[0083] Minimum thickness (mm) 2.5 Thickness at the top (mm) 2.9 Mass (g) 38.9 Spacing between relative bearing points of each sample (mm) 100 Radius of each recess (mm) 5 Repeating pitch of the recess (mm) 4.36

[0084] Nine identical samples B1-B9 each have according to Figure 10-11 The textured main surface, compared to Figure 8-9 The high-period (i.e., lower-frequency) repetitions have semi-cylindrical recesses with symmetrical longitudinal axes parallel to each other, and each sample B1-B9 has the characteristics described in detail in Table 2 below.

[0085] [Table 2]

[0086] Minimum thickness (mm) 2.5 Thickness at the top (mm) 3.6 Mass (g) 41.7 Spacing between relative bearing points of each sample (mm) 100 Radius of each recess (mm) 5 Repeating pitch of the recess (mm) 6.95

[0087] Six identical “contrast” samples C1-C6, each with two smooth master surfaces, have the characteristics described in detail in Table 3 below.

[0088] [Table 3]

[0089] Thickness (mm) 2 Mass (g) 29.7 Spacing between relative bearing points of each sample (mm) 100

[0090] The six identical “contrast” samples D1-D6, each with two smooth master surfaces, have the characteristics described in detail in Table 4 below.

[0091] [Table 4]

[0092] Thickness (mm) 3 Mass (g) 44.25 Spacing between relative bearing points of each sample (mm) 100

[0093] Five identical “contrast” samples E1-E5, each with two smooth master surfaces, have the characteristics described in detail in Table 5 below.

[0094] [Table 5]

[0095] Thickness (mm) 4 Mass (g) 56.75 Spacing between relative bearing points of each sample (mm) 100

[0096] Five identical “contrast” samples F1-F5, each with two smooth master surfaces, have the characteristics described in detail in Table 6 below.

[0097] [Table 6]

[0098] Thickness (mm) 5 Mass (g) 73 Spacing between relative bearing points of each sample (mm) 100

[0099] Impact testing was applied to these samples and the results.

[0100] use Figure 6 The image shows a tower of falling heavy objects, beneath which one can be seen... Figure 1 The pipes of the type shown according to the invention will undergo these impact tests. Based on the known mechanical principle E = mgz (where m is mass, g is gravitational acceleration, and z is the drop height), the impact energy is varied using a spherical impactor with a diameter equal to 16 mm (for samples A and B, the radius of the impactor is greater than the radius of each semi-cylindrical recess). A constant drop height of 1 m is selected on the sample to release a mass m with an increased value. The sample is placed (either flat, or, for bending impacts, on two spaced-apart supports) below a drop weight tower. The purpose of the impact test is to determine the limiting impact energy value, beyond which each sample exhibits visible damage, such as cracks or breakage.

[0101] according to Figure 7 The first sample :

[0102] Compared to a first smooth sample with the same thickness, the impact test performed on a first sample having a textured main surface according to a first embodiment of the invention showed an improved limiting impact energy before visible damage, indicating improved impact resistance relative to the latter.

[0103] according to Figure 8-9 The second sample A1-A6 :

[0104] Table 7 below details the test results for each sample A1-A6 in terms of impact energy, the condition of the sample (good or bad) after the first impact and the possible second impact at a given impact energy, and the identification of visible damage after each impact (a commentary on the textured outer side of each impacted sample, assuming no breakage after each impact).

[0105] [Table 7]

[0106]

[0107] Table 7 shows that the ultimate impact energy of samples A1-A6 before breakage is 3.5J.

[0108] according to Figure 10-11 The second sample B1-B9 :

[0109] Table 8 below details the test results for each sample B1-B9 in terms of impact energy, the condition of the sample (good or bad) after the first impact and the possible second impact at a given impact energy, and the identification of visible damage after each impact (a commentary on the textured outer side of each sample after impact, assuming no breakage after each impact).

[0110] [Table 8]

[0111]

[0112]

[0113] Table 8 shows that the ultimate impact energy of samples B1-B9 before breakage is 3.8J.

[0114] according to Figure 12 Comparison samples C1-C6 :

[0115] Table 9 below details the test results for each sample C1-C6 in terms of impact energy, the condition of the sample (good or bad) after the first impact and the possible second impact at a given impact energy, and the identification of visible damage after each impact (a commentary on the textured outer side of each impacted sample, assuming no breakage after each impact).

[0116] [Table 9]

[0117]

[0118] Table 9 shows that the ultimate impact energy of samples C1-C6 before breakage is less than 2.0 J.

[0119] according to Figure 13 Comparison samples D1-D6:

[0120] Table 10 below details the test results for each sample D1-D6 in terms of impact energy, the condition of the sample (good or bad) after the first impact and the possible second impact at a given impact energy, and the identification of visible damage after each impact (a commentary on the textured outer side of each impacted sample, assuming no breakage after each impact).

[0121] [Table 10]

[0122]

[0123] Table 10 shows that the ultimate impact energy of samples D1-D6 before breakage was 2.0 J.

[0124] according to Figure 14 Comparison samples E1-E5 :

[0125] Table 11 below details the test results for each sample E1-E5 in terms of impact energy, the condition of the sample (good or bad) after the first impact and the possible second impact at a given impact energy, and the identification of visible damage after each impact (a commentary on the textured outer side of each impacted sample, assuming no breakage after each impact).

[0126] [Table 11]

[0127]

[0128] Table 11 shows that the ultimate impact energy of samples E1-E5 before fracture was between 3.5 and 4.0 J.

[0129] according to Figure 15 Comparison samples F1-F5 :

[0130] Table 12 below details the test results for each sample F1-F5 in terms of impact energy, the condition of the sample (good or bad) after the first impact and the possible second impact at a given impact energy, and the identification of visible damage after each impact (a commentary on the textured outer side of each impacted sample, assuming no breakage after each impact).

[0131] [Table 12]

[0132]

[0133] Table 11 shows that the ultimate impact energy of samples F1-F5 before fracture is between 7.0 and 7.5 J.

[0134] Compared to a smooth component of the same thickness, these tests demonstrate that for a component according to the invention, [the results are as follows]. Figure 7-11 The textured surface allows it to delay the onset of cracks after impact, as the protrusions formed by the ridges and recesses are crushed during the cushioning of these impacts, and as early warning monitoring of the textured component according to the invention is activated.

[0135] In particular, compared with samples C and D of the same thickness of 2mm-3mm (Tables 9 and 10), Tables 7 and 8 show that the textured surfaces according to the second embodiment of the invention provide samples A and B, to which they are incorporated, with a significantly increased ultimate impact energy before breakage, and thus significantly improved impact resistance.

[0136] Table 11 shows that the thickness of the “comparison” sample (see sample E) needs to be increased to 4 mm in order to obtain the same ultimate impact energy (between 3.5 and 4.0 J) before breakage, that is, for components A and B according to the two embodiments of the present invention, the mass gain is approximately 25%.

[0137] These results also show that the ultimate impact energy before fracture can be increased by increasing the thickness of the sample (see Tables 7-8 for samples A and B, and Tables 9-12 for sample CF).

[0138] The results in Tables 7-8 of the second embodiment of the textured surface according to the invention further show that a configuration in which ridges and depressions are spaced with a high repetition period (i.e., a reduced frequency or repetition pitch that makes the ridges / depressions more spaced apart) constitutes a preferred exemplary embodiment of the invention, assuming that the ultimate impact energy before fracture is... Figure 10-11 It is 3.8J, while for Figure 8-9 It is 3.5J.

[0139] and Figure 8 and 9 Compared to the variants of the present invention, Figure 10-11 Preferred examples of the invention are particularly notable due to the higher “drop” (i.e., the thickness difference between the bottom of the ridge and the recess) and the increased thickness of the components.

Claims

1. An injection-molded thermoplastic matrix component capable of forming a conduit (1, 1') for use in an aircraft or spacecraft, the component having at least partially rotationally symmetrical outer surfaces (2, 2'), wherein the outer surfaces include a plurality of integrally injection-molded recesses (6, 6'), the integrally injection-molded recesses being paired and connected to each other by ridges (7, 7'), and wherein: - Measured in a direction d perpendicular to the ridges defining each integrally injection-molded recess, each integrally injection-molded recess has a maximum lateral dimension D between 3-10 mm between adjacent pairs of ridges, and - Each ridge has a top, the top having a lateral width L measured in the direction d, where L <D, Each integrally injection-molded recess (6, 6') has a generally spherical or cylindrical recessed surface.

2. The component according to claim 1, wherein, L<0.5D.

3. The component according to claim 2, wherein, L<0.2D.

4. The component according to claim 1, wherein, The recessed surface is defined by a radius of curvature R associated with the maximum lateral dimension D, where 0.5D < R < 2D.

5. The component according to claim 4, wherein, The recessed surface is defined by a radius of curvature R associated with the maximum lateral dimension D, where 0.7 D < R < 1.5 D.

6. The component according to claim 1, wherein, The component has a thickness difference measured between 0.2 mm and 2 mm from its outer surface (2, 2') to its radially opposite inner surface (5, 5'). The thickness difference is between the bottom (6a) of each ridge (7, 7') and the adjacent integrally injection-molded recess (6, 6').

7. The component according to claim 6, wherein, The thickness difference of the component is between 0.3 mm and 1.3 mm.

8. The component according to claim 1, wherein, The integrally injection-molded recesses (6, 6') are identical and regularly spaced apart to form at least one circumferential row of integrally injection-molded recesses between the two open ends (3, 3' and 4, 4') of the component, wherein the or each circumferential row extends above the periphery of the outer surface (2, 2') at a repeating pitch, the pitch having a value equal to D+L between two consecutive integrally injection-molded recesses in the or each circumferential row.

9. The component according to any one of claims 6 and 8, wherein, The thickness difference of the component: - When the pitch between the integrally injection-molded recesses (6, 6') is between 6 mm and 8 mm, it is between 0.8 mm and 1.3 mm; or - When the pitch between the integrally injection-molded recesses (6, 6') is between 3 mm and 5 mm, it is between 0.3 mm and 0.7 mm.

10. The component according to claim 9, wherein, The thickness difference of the component: - When the pitch between the integrally injection-molded recesses (6, 6') is between 6 mm and 8 mm, it is between 0.8 mm and 1.3 mm, where 0.7 D < R < D, or - When the pitch between the integrally injection molded recesses (6, 6') is between 3 mm and 5 mm, it is between 0.3 mm and 0.7 mm, where D < R < 1.3 D.

11. The component according to claim 9, wherein, The integrally injection-molded recesses (6, 6') form a plurality of spaced-apart circumferential rows above the outer surface (2, 2'), each circumferential row having an integrally injection-molded recess having a generally spherical recessed surface and being discontinuously formed on the outer surface in the form of a golf ball pit.

12. The component according to claim 8, wherein, The integrally injection-molded recesses (6, 6') form a circumferential row on the outer surface (2, 2'), and the integrally injection-molded recesses of the circumferential row each have a continuous, generally semi-cylindrical recessed surface on the outer surface.

13. The component according to claim 1, wherein, The component has two open ends (3, 3' and 4, 4'), each of which has a generally circular, elliptical or polygonal end perimeter independently of each other.

14. The component according to claim 1, wherein, The component is composed of a polymer composition based on at least one thermoplastic polymer selected from polyamide (PA), polyphenylene sulfide (PPS), polyetherimide (PEI), polyacetamide terephthalate (PPA), polyphenylene sulfone (PPSU), polyether ether ketone (PEEK), polyarylether ether ketone (PAEK), and polyvinylidene fluoride (PVDF).

15. The component according to claim 14, wherein, The composition includes a reinforcing member, the reinforcing member comprising: - Reinforcing fillers distributed in the composition, selected from organic and inorganic fillers including carbon black and carbon nanotubes, and / or - Reinforcing fibers selected from glass fiber and carbon fiber are used to form unidirectional or woven reinforcements.

16. The component according to claim 15, wherein, The reinforcing element comprises discontinuous glass fiber with a mass fraction between 20% and 40%.

17. A method for manufacturing the component according to claim 1, wherein, The step of injection molding of a polymer composition is performed in a model configured to reverse the integral injection molded recesses (6, 6') and ridges (7, 7'), the polymer composition comprising the thermoplastic matrix and possible reinforcements, the reinforcements comprising reinforcing fillers and / or reinforcing fibers distributed in the composition.

18. A conduit (1, 1') for an aircraft or spacecraft, the conduit being configured to be installed within the aircraft and to convey a liquid or gaseous fluid therein, wherein the conduit includes or is constituted by a component according to any one of claims 1-17, the component being resistant to cracks caused by tool impacts near the conduit during installation or maintenance operations.

19. The conduit (1, 1') according to claim 18, wherein, The duct forms an air inlet device for the air conditioning unit of the aircraft, so as to supply conditioned air to at least one compartment or passenger compartment of the aircraft, the duct comprising: - A first opening end (3, 3'), the first opening end having a generally circular or elliptical periphery of a conduit configured to connect in a leak-proof manner to an opening in the cabin or passenger compartment of the air conditioning unit, and - A second opening end (4, 4'), having a wider cross-section relative to the first end, the second opening end being configured to connect to the air-to-air heat exchanger of the aircraft.

20. The pipe (1, 1') according to claim 19, wherein, The second opening end (4, 4') has a generally polygonal or rectangular periphery configured to connect to an air-to-air heat exchanger of the aircraft located outside the cabin or passenger compartment.

21. The pipe (1, 1') according to claim 19, wherein, The duct has an increasing cross-sectional area from the first end (3, 3') to the second end (4, 4'), and the duct is provided with a device for connection to the air conditioning unit.

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