EP0568573A1 - Element structurel alveolaire - Google Patents
Element structurel alveolaireInfo
- Publication number
- EP0568573A1 EP0568573A1 EP92903277A EP92903277A EP0568573A1 EP 0568573 A1 EP0568573 A1 EP 0568573A1 EP 92903277 A EP92903277 A EP 92903277A EP 92903277 A EP92903277 A EP 92903277A EP 0568573 A1 EP0568573 A1 EP 0568573A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cells
- cellular
- component
- face
- panel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 230000001413 cellular effect Effects 0.000 title claims abstract description 85
- 239000000463 material Substances 0.000 claims description 28
- 229920001169 thermoplastic Polymers 0.000 claims description 25
- 239000004416 thermosoftening plastic Substances 0.000 claims description 25
- 239000004744 fabric Substances 0.000 claims description 12
- 239000000843 powder Substances 0.000 claims description 7
- 238000005245 sintering Methods 0.000 claims description 7
- 238000003491 array Methods 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- 241000264877 Hippospongia communis Species 0.000 abstract 2
- 238000013016 damping Methods 0.000 abstract 1
- 239000012815 thermoplastic material Substances 0.000 abstract 1
- 210000004027 cell Anatomy 0.000 description 55
- 239000000853 adhesive Substances 0.000 description 6
- 230000001070 adhesive effect Effects 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 6
- 239000003822 epoxy resin Substances 0.000 description 5
- 229920000647 polyepoxide Polymers 0.000 description 5
- 229920005989 resin Polymers 0.000 description 5
- 239000011347 resin Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 3
- 239000004696 Poly ether ether ketone Substances 0.000 description 3
- 210000003850 cellular structure Anatomy 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229920001568 phenolic resin Polymers 0.000 description 3
- 239000005011 phenolic resin Substances 0.000 description 3
- 229920002530 polyetherether ketone Polymers 0.000 description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- 229920000784 Nomex Polymers 0.000 description 2
- 239000004760 aramid Substances 0.000 description 2
- 229920003235 aromatic polyamide Polymers 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 239000004763 nomex Substances 0.000 description 2
- -1 polyphenylene Polymers 0.000 description 2
- 239000004962 Polyamide-imide Substances 0.000 description 1
- 239000004697 Polyetherimide Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 229920000265 Polyparaphenylene Polymers 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 229920006332 epoxy adhesive Polymers 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000013521 mastic Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 229920001643 poly(ether ketone) Polymers 0.000 description 1
- 229920002312 polyamide-imide Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920001601 polyetherimide Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229920006259 thermoplastic polyimide Polymers 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
- B32B3/10—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material
- B32B3/12—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
- B32B5/024—Woven fabric
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/16—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer formed of particles, e.g. chips, powder or granules
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D33/00—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for
- B64D33/02—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
- E04C2/30—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure
- E04C2/34—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts
- E04C2/36—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts spaced apart by transversely-placed strip material, e.g. honeycomb panels
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/172—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using resonance effects
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2305/00—Condition, form or state of the layers or laminate
- B32B2305/02—Cellular or porous
- B32B2305/024—Honeycomb
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/10—Properties of the layers or laminate having particular acoustical properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/10—Properties of the layers or laminate having particular acoustical properties
- B32B2307/102—Insulating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2607/00—Walls, panels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D33/00—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for
- B64D33/02—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes
- B64D2033/0206—Arrangements in aircraft of power plant parts or auxiliaries not otherwise provided for of combustion air intakes comprising noise reduction means, e.g. acoustic liners
Definitions
- the present invention relates to structural cellular components and is particularly although not exclusively concerned with a structural cellular component for a noise attenuation panel for use in the attenuation of noise in aero engines.
- a noise attenuation panel having a backing sheet, a facing sheet and a cellular core having a multiplicity of opened ended juxtaposed cells.
- the backing sheet extends across the open ends of the cells at the rear of the core and the facing sheet extends across the open ends of the cells at the front of the core.
- the facing sheet is made of a porous permeable thermoplastics material preferably produced by a powder sintering process and the backing sheet is imperforate and impermeable.
- the noise attenuation panel disclosed in GB-A-2223448 is proposed for use in reducing turbine engine noise and is formed as an integral part of an aero engine structure.
- the panels form part of a cowling surrounding a turbine engine inlet duct or be placed adjacent a high turbulence region of the fan of a turbofan engine.
- the cellular core in the panel specifically disclosed in GB2223448A is furthermore formed by cells having wall portions which extend parallel to each other and perpendicular to the backing and facing sheets.
- a structural cellular component for a noise attenuation panel comprising wall portions which provide bounding surfaces for an array of cells and which terminate at opposite faces of the component, characterised in that the wall portions or predetermined ones of the wall portions forming the cells extend to at least one of the faces of the component at an angle or angles inclined to the normal to that face.
- a first embodiment of the first aspect of the present invention is characterised in that the wall portions of the cellular component provide bounding surfaces for an array of juxtaposed cells which terminate in open ends at one of the faces of the component with the wall portions extending to that face at angles inclined to the normal to that face.
- the cells also terminate in open ends at the opposite face of the component with the wall portions extending to the opposite face at angles inclined to the normal to that face.
- the wall portions extend to the face or faces of the component along lines which are parallel to each other.
- the angle at which the wall portions are inclined to the normal to the or each face of the component is in excess of 20°.
- the cells are of constant cross-section with the lateral edges of each cell lying along lines parallel to each other.
- the cells are of hexagonal cross-section but in alternative embodiments of the invention the cells may conform to an isogrid or orthogrid pattern.
- the wall portions or predetermined ones of the wall portions extend to the face or each face of the component along lines which are not parallel to each other.
- the cells may be of pyramidal form or in the form of truncated pyramids.
- a noise attenuation panel comprising a cellular component part in the form of a component according to the first aspect of the invention, a backing component part extending across one face of the cellular component part at the rear thereof and a facing component part extending across the other face of the cellular component part at the front thereof.
- the facing component part comprises or includes an outer facing sheet which is made of a porous permeable thermoplastics material.
- the porous permeable thermoplastics material for the outer facing sheet is produced by powder sintering a thermoplastics material.
- the facing component part further includes an inner facing sheet made from an open square weave fabric having apertures constituted by the openings between adjacent warp and weft threads of the fabric.
- the cellular component part comprises an upper cellular element in the form of a component according to the first aspect of the invention, a lower cellular element in the.form of a component according to the first aspect of the invention and positioned beneath the upper cellular element and a septum sheet which extends across the lower cellular element at an upper face thereof and across the upper cellular element at the lower face thereof.
- the upper and lower cellular elements comprise identical arrays of cells inclined to the normal to the panel.
- the upper and lower cellular elements are arranged one above the other and the cells of the one are inclined to the normal to the panel in the same direction as the cells of the other.
- the two cellular elements are so positioned and arranged that the upper open ends of the cells of the upper cellular element are in registration with the open upper ends of the cells of the lower cellular element, whereby the lower open ends of the cells of the upper element are out of registration with the upper open ends of the cells of the lower element.
- the two cellular elements are so arranged that the lower open ends of the cells of the upper cellular element are in registration with the upper open ends of the cells of the lower cellular element, whereby the cells of the lower cellular element form a continuation of the cells of the upper cellular element.
- the upper and lower cellular elements are so positioned and arranged one above the other that the cells of the one element are inclined to the normal to the panel in a direction opposite to that of the cells of the other element.
- the septum sheet may be constructed from a porous permeable thermoplastics material or alternatively made of a stainless steel fabric.
- the upper cellular element or the lower cellular element or both may be made from an impermeable material or from a porous permeable thermoplastics material.
- an aero engine having a surface subjected to the passage across it of gaseous flow and a noise attenuation panel according to the second aspect of the invention so positioned that its front face forms the surface or part of the surface subjected to passage of the gaseous flow across it.
- Fig. 1 is a schematic isometric view from above of a noise attenuation panel embodying a structural cellular component according to a first embodiment of the invention
- Fig. 2 is a schematic cross section of an end region of the panel shown in Fig. 1, secured to a supporting channel member;
- Figs. 3, 4 and 5 are schematic cross sectional scrap- views of noise attenuation panels according to three further embodiments of the invention.
- Fig 6 is a schematic cross-section of an aero engine embodying noise attenuation panels according to the invention.
- the noise attenuation panel 10 comprises a backing sheet 11, a cellular core 12 and inner and outer facing sheets 13 and 14.
- the cellular core 12 comprises a multiplicity of open- ended juxtaposed cells 15 of hexagonal cross section to provide a honeycomb configuration in which the lateral edges 16 are (i) parallel to each other, (ii) lie in planes which are perpendicular to the backing sheet 11 and parallel to the edge 111 of the sheet 11 and (iii) lie on lines which are inclined to the normal to the backing sheet, whereby the length of the cells 15 between the backing sheet 11 and the inner facing sheet 13 is greater than the distance of separation of the two sheets 11 and 13.
- the backing sheet 11 is unperforated and made from an impermeable sheet material, as shown in Fig. 2, and is secured by an epoxy resin adhesive El to the lower face of the cellular core 12.
- the inner facing sheet 13 is made from an open square weave fabric formed from a carbon fibre/resin matrix composite material and the weave is such as to provide apertures constituted by the openings between adjacent warp and weft threads of the fabric.
- the fabric is preferably so woven as to produce a proportion of open aperture area relative to the total surface area of the sheet of around 30%. At the same time, the fabric is so woven that a relatively large number of its apertures are contained within the bounds of each cell 15 of the cellular core 12.
- the outer facing sheet 14 comprises a sheet of a porous permeable thermoplastics material produced by powder sintering the thermoplastic.
- suitable thermoplastics materials include polyether ketone, polyether ether ketone, polyaromatic ketone, polyphenylene sulphide, polyamide-imide, thermoplastic polyimide, polyether-imide, polyurethane and polyethylene.
- the outer facing sheet 14 is bonded to the inner facing sheet 13 and the inner facing sheet 13 is, as shown in Fig.2, secured to the upper face of the cellular core 12 by means of an epoxy resin adhesive E2.
- the inner woven facing sheet 13 in a part cured condition and to bring the outer facing sheet 14 into contact with it during a final curing step so that the resin serves to bond the two sheets together.
- the combined sheets 13 and 14 may then be secured to the upper face of the cellular core 12 using the epoxy resin adhesive E2.
- the epoxy adhesives El and E2 may for example be obtained from Ciba-Geigy Plastics & Additives Company Limited of Cambridge, England. Adhesives and resins need not however be epoxy resin adhesives, but could for example be a phenolic, polyimide or thermoplastics resin.
- the backing sheet 11 is imperforate and made of a non- porous impermeable material and may be made of any of the following materials:-
- thermoplastic where for example the thermoplastic is polyether ether ketone, the material being automatically tape wound or hand laid.
- thermoplastic is polyether ether ketone, the material being automatically tape wound or hand laid.
- carbon/epoxy resin is a carbon/thermoplastic composite where for example the thermoplastic is polyether ether ketone, the material being automatically tape wound or hand laid.
- the cellular core 12 in the embodiment of the invention illustrated is made from a non-porous impermeable sheet of any of the following materials:-
- thermoplastic such as polyether ether ketone.
- NOMEX being a registered trade mark for an aramid fibre paper impregnated with various resins to produce a structural material.
- aramid is meant an aromatic polya ide polymer.
- the cellular core 12 may however if desired be made of a porous permeable thermoplastics material and may be in the same form as the outer facing sheet 14.
- the panel 10 is of arcuate form, possibly of double curvature, and is embodied as a structural part of a duct of a nose cowl of a turbofan aero engine, the panel 10 being one of several arcuate panels disposed just upstream of the fan of the engine. It is, of course, of vital importance that the panel does not deteriorate in use and, in particular, that no part of it becomes detached from its supporting structure.
- the structure will usually include supporting channel members of which only one member 17 is shown in Fig. 2.
- the panel 10 is secured to the member 17 by bonding the inner facing sheet 13 to an outer face of a flange 18 of the channel member 17 using a carbon bond 19 and by bonding the backing sheet 11 to the outer face of a flange 20 of the channel member 17 using a carbon to carbon bond 21.
- the gap between the panel 10 and the base 22 of the channel member 17 may be sealed or closed by use of a mastic 23.
- a panel having an outer facing sheet 14 made of a porous thermoplastics material as described with reference to Figs. 1 and 2 has been found to give rise to several advantages over the panels of the prior proposals, including the following:-
- the cellular structure of the facing sheet when produced by the powder sintering technique can be made to meet permeability requirements over a wide range.
- the cellular structure may be made permeable to gaseous flow over a wide range of tightly controlled flow and resistance requirements which will be engine dependent and non permeable to a wide range of liquids and solid contaminants.
- thermoplastic component parts do not have the problem of metal corrosion
- the acoustic absorbing properties of the panel are improved by an appropriate inclining of the cells of the core to the backing and facing sheets, thereby extending the length of the cells without increasing the panel thickness and thereby extending the sound attenuation of the panel to the lower frequencies generated in the large diameter UHB ratio turbofan engines.
- a panel according to a second embodiment of the invention is illustrated, in which the cellular core 12 of the embodiment of the invention described with reference to Figs. 1 and 2 is replaced by a split cellular core comprising an upper cellular element 121 having a multiplicity of open-ended juxtaposed inclined cells 151, a lower cellular element 122 having a further multiplicity of open-ended juxtaposed inclined cells 152 and a septum sheet 24 which extends across the ends of the cells 152 of the lower cellular element 122 at the upper face thereof and the ends of the cells 151 of the upper cellular element 121 at the lower face thereof.
- the cells of the two cellular elements 121 and 122 form identical arrays of the inclined cells as described with reference to Fig 1 and are arranged one above the other.
- the upper open ends of the cells 151 and 152 are arranged one above the other, as a consequence of which the lower open ends of the cells 151 of the upper element 121 are not in alignment with the upper open ends of the cells 152 of the lower element 122.
- the backing sheet 11, the inner and outer facing sheets 13 and 14 and the upper and lower cellular elements 121 and 122 of the panel shown in Fig. 3 are constructed and bonded together in the same manner as the sheet 11, core 12 and facing sheets 13 and 14 of the embodiment described with reference to Figs. 1 and 2, with the backing sheet 11 being secured to the lower face of the lower cellular element 122 and the inner and outer facing sheets 13 and 14 being secured to the upper face of the upper element 121.
- the septum sheet 24 is likewise bonded to adjacent faces of the cellular elements 121 and 122. It is constructed from a porous permeable thermoplastics material and may take the same form as that of the outer facing sheet 14 of the panel described with reference to Figs. 1 and 2.
- the inner facing sheet 13 of the panel described with reference to Figs.l and 2 is omitted and the outer facing sheet 14, which is made of the porous thermoplastics material, is adhered direct to the upper face of the cellular core 12 using adhesive E2.
- a fourth embodiment of the invention is illustrated which corresponds to the embodiment of the invention described with reference to Fig. 3, except that the cells 151 of the upper cellular element 121 are inclined in one direction and the cells 152 of the lower element 122 are inclined in the opposite direction and except insofar as the inner facing sheet 13 is omitted and the outer facing sheet 14 is adhered direct to the face of the upper cellular element 121 in the manner described for the panel illustrated in Fig. 4.
- the panel described with reference to Fig. 3 may be modified by making the upper cellular element 121 or the lower cellular element 132 or both of a porous thermoplastics material and may be made 'from any of the materials proposed for the outer facing sheet 14 of the panel described with reference to Figs, l and 2.
- the septum sheet 24 in the panels illustrated in Figs. 3 and 5 is described as being made of a porous thermoplastics material. It may however if desired be made of a stainless steel fabric or any of the above- mentioned materials which are suitable for the inner facing sheet 13, the requirement of course being that the sheet is either porous and permeable, perforated or apertured.
- cells 15 of hexagonal cross section have been provided. It will however be appreciated that cells of other cross sections, for example conforming to an isogrid or orthogrid pattern, can alternatively be used.
- the cells 15 are prismatic in form, that is to say, are of constant cross section with the lateral edges 16 of each cell 15 lying along lines parallel to each other. It will however be appreciated that cells of non-constant cross section may be provided in which the lateral edges or some of the lateral edges of each cell 15 are not equally inclined, as for example where the cells are of pyramidal form or in the form of truncated pyramids, so as to provide cells in which the effective length varies within the cell.
- an aero engine 25 is schematically illustrated and includes a turbofan power unit 26 mounted within a nacelle 27 suspended from a pylon 32.
- the nacelle 27 includes a nose cowl 28 having an outer wall 29 and an inner wall 30.
- the inner wall 30 is in part formed by noise attenuation panels P which may take the form of panels as described and illustrated with reference to Figs. 1 to 5.
- the panels P are arranged to form part of the inner wall of the nose cowl 28 and serve to reduce noise created by the high speed flow of air passing through the duct 31 into the power unit 26, as well as to reduce noise generated by the fan blades of the unit 26 .
- the panels in Fig. 6 are not employed to reduce air noise by a reduction of the air speed by passage of the air through the panels, but by contrast acoustic attenuation is achieved without affecting the speed of the air which generates the noise, that is to say, the air does not pass through the noise attenuation panels P.
- the power unit is carried by the wing mounted pylon 32. It will however be appreciated that the noise attenuation panels according to the present invention may be equally well be employed for reducing noise in other aero engine installations.
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Aviation & Aerospace Engineering (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Textile Engineering (AREA)
- Wood Science & Technology (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Laminated Bodies (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
- Catalysts (AREA)
Abstract
Un élément structurel alvéolaire (12) destiné à un panneau (10) amortissant le bruit, comprend des parois qui forment des surfaces de délimitation pour un réseau d'alvéoles (15) et qui aboutissent à des faces opposées de l'élément. Les parois délimitant les alvéoles (15) rejoignent au moins l'une des faces de l'élément à un angle ou à des angles oblique(s) par rapport à cette face. Le panneau (10) d'amortissement de bruit se compose de l'élément alvéolaire (12), d'une partie en forme d'élément dorsal (11) qui s'étend sur toute la face arrière de l'élément alvéolaire (12) et d'un élément de revêtement (13, 14) qui s'étend sur toute la face avant de l'élément alvéolaire (12). L'élément de revêtement (13, 14) comprend une feuille de revêtement externe (14) composée d'un matériau thermoplastique perméable et poreux. Le panneau est destiné à être utilisé dans un moteur d'avion, au niveau d'une surface sur laquelle passe un écoulement gazeux, et est placé de telle façon que sa face avant constitue la surface sur laquelle passe l'écoulement gazeux.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9101395 | 1991-01-22 | ||
GB919101395A GB9101395D0 (en) | 1991-01-22 | 1991-01-22 | Structural cellular component |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0568573A1 true EP0568573A1 (fr) | 1993-11-10 |
Family
ID=10688828
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP92903277A Withdrawn EP0568573A1 (fr) | 1991-01-22 | 1992-01-21 | Element structurel alveolaire |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0568573A1 (fr) |
JP (1) | JPH06504629A (fr) |
AU (1) | AU1170792A (fr) |
CA (1) | CA2092410A1 (fr) |
GB (2) | GB9101395D0 (fr) |
WO (1) | WO1992012854A1 (fr) |
Families Citing this family (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2732336B1 (fr) | 1995-03-29 | 1997-06-20 | Aerospatiale | Procede d'elaboration d'une structure allegee en sic, du type sandwich a ame en nid d'abeilles et structure ainsi obtenue |
FR2735166B1 (fr) * | 1995-06-08 | 1997-08-29 | Aerospatiale | Procede de fabrication d'un panneau ou analogue a proprietes structurale et acoustique et panneau ainsi obtenu |
FR2735093B1 (fr) * | 1995-06-09 | 1997-08-29 | Aerospatiale | Panneau sandwich en materiau composite et procede de fabrication |
GB0016149D0 (en) * | 2000-06-30 | 2000-08-23 | Short Brothers Plc | A noise attenuation panel |
US7328771B2 (en) | 2004-07-27 | 2008-02-12 | United Technologies Corporation | Zero acoustic splice fan case liner |
ES2542905T3 (es) * | 2009-09-11 | 2015-08-12 | Stora Enso Re-Board Ab | Tablero y método para la fabricación de un tablero |
FR2951854B1 (fr) * | 2009-10-22 | 2014-09-12 | Onera (Off Nat Aerospatiale) | Dispositif d'absorption acoustique |
GB2485165A (en) * | 2010-11-03 | 2012-05-09 | Timothy John Sweatman | A laminated panel for acoustic insulation |
US9096316B2 (en) * | 2012-02-01 | 2015-08-04 | Textron Innovations Inc. | Optimized core for a structural assembly |
US10294815B2 (en) | 2012-03-01 | 2019-05-21 | The Boeing Company | SPF/DB structure for attenuation of noise from air flow |
GB201209658D0 (en) | 2012-05-31 | 2012-07-11 | Rolls Royce Plc | Acoustic panel |
RU2637276C2 (ru) * | 2013-06-13 | 2017-12-01 | Зе Боинг Компани | Конструкция на основе суперпластического формообразования/диффузного связывания для ослабления шума от потока воздуха |
US10184398B2 (en) | 2013-10-17 | 2019-01-22 | Rohr, Inc. | Acoustic structural panel with slanted core |
FR3024708B1 (fr) * | 2014-08-06 | 2018-03-02 | Safran Nacelles | Panneau a ame alveolaire pour nacelle d’aeronef et procede de fabrication d’un tel panneau |
FR3026045B1 (fr) * | 2014-09-24 | 2016-12-09 | Faurecia Automotive Ind | Procede de fabrication d'une piece composite a base de resine aqueuse et piece composite issue d'un tel procede |
FR3031142B1 (fr) | 2014-12-24 | 2017-03-24 | Aircelle Sa | Panneau d’attenuation acoustique pour nacelle de turboreacteur |
US9650963B2 (en) * | 2015-01-29 | 2017-05-16 | Rohr, Inc. | Acoustic structural panel with herringbone core |
US9656452B2 (en) | 2015-03-12 | 2017-05-23 | Rohr, Inc. | Method of forming an acoustic bond panel with insertable acoustic assemblies |
US10800117B2 (en) | 2015-03-12 | 2020-10-13 | Rohr, Inc. | Method of forming an acoustic bond panel with insertable acoustic assemblies |
US9708930B2 (en) | 2015-12-09 | 2017-07-18 | Rohr, Inc. | Multi-degree of freedom acoustic panel |
US10487943B2 (en) | 2016-07-12 | 2019-11-26 | United Technologies Corporation | Multi-ply seal ring |
US10577117B2 (en) * | 2017-08-04 | 2020-03-03 | Hexcel Corporation | Angled acoustic honeycomb |
GB201903716D0 (en) * | 2019-03-19 | 2019-05-01 | Rolls Royce Plc | Acoustic liner panel and containment for a gas turbine engine |
CN114074753A (zh) * | 2020-08-19 | 2022-02-22 | 中国航发商用航空发动机有限责任公司 | 蜂窝件及其制造方法、蜂窝装置、声衬和航空发动机 |
FR3126334B1 (fr) | 2021-08-30 | 2023-07-21 | Safran Nacelles | Procédé de fabrication d’un panneau acoustique à cavités obliques |
FR3126340B1 (fr) | 2021-08-30 | 2023-11-03 | Safran Nacelles | Panneau acoustique à cavités obliques |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA956895A (en) * | 1970-12-18 | 1974-10-29 | American Cyanamid Company | Sound absorbing laminate |
US3821999A (en) * | 1972-09-05 | 1974-07-02 | Mc Donnell Douglas Corp | Acoustic liner |
US3831710A (en) * | 1973-01-24 | 1974-08-27 | Lockheed Aircraft Corp | Sound absorbing panel |
US3819007A (en) * | 1973-04-27 | 1974-06-25 | Lockheed Aircraft Corp | Controllable laminar sound absorptive structure |
GB1502314A (en) * | 1974-04-08 | 1978-03-01 | Lockheed Aircraft Corp | Cellular sound absorptive structure |
US4265955A (en) * | 1978-05-01 | 1981-05-05 | The Boeing Company | Honeycomb core with internal septum and method of making same |
US4318453A (en) * | 1979-09-17 | 1982-03-09 | Rohr Industries, Inc. | Double layer attenuation panel |
US4433021A (en) * | 1982-09-22 | 1984-02-21 | Rohr Industries, Inc. | Sound attenuation sandwich panel including barrier material for corrosion control |
GB8817669D0 (en) * | 1988-07-25 | 1988-09-01 | Short Brothers Ltd | Means for attenuating sound energy |
FR2660787B1 (fr) * | 1990-04-06 | 1996-06-21 | Technologies Speciales Ingenie | Ecran anechouide. |
-
1991
- 1991-01-22 GB GB919101395A patent/GB9101395D0/en active Pending
-
1992
- 1992-01-21 JP JP4503571A patent/JPH06504629A/ja active Pending
- 1992-01-21 GB GB9201243A patent/GB2252075B/en not_active Expired - Fee Related
- 1992-01-21 WO PCT/GB1992/000118 patent/WO1992012854A1/fr not_active Application Discontinuation
- 1992-01-21 EP EP92903277A patent/EP0568573A1/fr not_active Withdrawn
- 1992-01-21 CA CA002092410A patent/CA2092410A1/fr not_active Abandoned
- 1992-01-21 AU AU11707/92A patent/AU1170792A/en not_active Abandoned
Non-Patent Citations (1)
Title |
---|
See references of WO9212854A1 * |
Also Published As
Publication number | Publication date |
---|---|
AU1170792A (en) | 1992-08-27 |
GB9201243D0 (en) | 1992-03-11 |
GB9101395D0 (en) | 1991-03-06 |
CA2092410A1 (fr) | 1992-07-23 |
JPH06504629A (ja) | 1994-05-26 |
GB2252075B (en) | 1994-10-19 |
WO1992012854A1 (fr) | 1992-08-06 |
GB2252075A (en) | 1992-07-29 |
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