Title of Invention

METHOD FOR PRODUCTION OF A THREE-DIMENSIONAL CURVED FIBRE COMPOSITE MATERIAL STRUCTURAL COMPONENT

Abstract

The invention relates to a method for production of a three-dimensional curved fibre composite material structural component, having a defined flexible girder profile cross-section with at least one web region and at least one flange region connected thereto with 0°-fibres, comprising the following steps: a) preparation of a planar base non-woven fibre which may be laid in at least one plane, b) arrangement of a unidirectional non-woven fibre strip with 0°-fibres on a part section of the prepared non-woven fibre, laying the at least one flange region of the fibre composite material structural component to be produced, c) fixing the non-woven fibre strip to the base non-woven fibre by stitching with at least one first fixing seam to form a planar pre-made-up non-woven fibre strip, provided with a flange strip region containing the uni-directional non-woven fibre strip and a web strip region with no uni-directional non-woven fibre strip, d) preparation of the planar pre-made-up non-woven fibre strip in a working plane, e) laying the pre-made-up non-woven fibre strip according to the desired shape of the three-dimensional curved fibre composite material structural component to be produced, the flange strip region being bent out of the working plane with relation to the web strip region about a single axis around at least one bending axis, running perpendicular to the 0°-fibres and parallel to the strip plane of the uni-directional non-woven fibre strip and the web strip region of the non-woven fibre strip laid essentially only in the working plane wherein the fibre arrangement is deformed and f) stitching of the pre-made-up non-woven fibre strip on a support material laid in at least one plane by means of at least one second fixing seam, applied to a transition region between the flange strip region and the web strip region only in the web strip region such that a stabilised three-dimensionally curved first sub-non-woven fibre blank corresponding to the fibre composite material structure component is formed.

Full Text

FORM 2 THE PATENT ACT 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10, and rule 13) TITLE OF INVENTION METHOD FOR PRODUCTION OF A THREE-DIMENSIONAL CURVED FIBER COMPOSITE MATERIAL STRUCTURAL COMPONENT APPLICANT(S) a) Name : b) Nationality : c) Address : EUROCOPTER DEUTSCHLAND GMBH GERMAN Company INDUSTRIESTRASSE 4, 86609 DONAUWOERTH GERMANY PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed : - The invention relates to a method for the production of a three-dimensionally curved fiber composite material structural component. Such fiber composite material structural components are used, for example, as spars or formers, that is to say, as load-bearing components of an aircraft wing. The beam-shaped spar has the function of absorbing the lateral forces and flexural moments stemming from the aerodynamic and inertial forces. Spars are also used, for example, in rotor blades, for example, of wind turbines and helicopters. Moreover, spars, spars formers consisting of fiber composite material structural components, are also used in the tail assemblies of aircraft. As a rule, such spars consist of essentially two components that fulfill different functions. The so-called flanges absorb the normal forces from the flexural moments. The shear web that joins the flanges absorbs the lateral forces and conducts the shear between the flanges. In the case of aircraft with a plastic construction, in which the spars are made of a fiber composite material, the flanges are made of a unidirectional layer (abbreviated UD layer). The shear web consists of a woven fabric or of a laid scrim at, for example, 45°, e.g. the so-called Balanced Ply Laminate 45. Unidirectional layer is the designation for a layer of a fiber composite in which all of the fibers are oriented in one single direction and it is thus also referred to as a 0° fiber laid scrim, that is to say, the fibers are aligned in the lengthwise direction of the tape. Here, the fibers are assumed to be ideally parallel and distributed homogeneously. The unidirectional layer is transversally isotropic. All fiber prepregs, for example, fabrics, nonwovens, multiaxial laid scrims, used in fiber composites can be structured from unidirectional layers. A woven fabric is a crosswise composite structure that is made up of two unidirectional layers that are positioned at an angle of 90° with respect to each other. In wing spars as fiber composite material structural components, it is a known procedure to use the unidirectional layer as a flange that absorbs the normal forces from the flexural moments. In addition to the unidirectional laid scrim for the flanges, the fiber composite material structural component comprises the shear web that is made of a woven fabric or of a laid scrim, whereby in the case of a woven fabric, an undulation of the fibers is created by the weaving and this can lead to a lowering of the fiber-parallel compressive strength. In a laid scrim, which is held together by paper or vane stitching, the fibers ideally lie parallel and stretched. In order to produce a preform with the three-dimensional shape of a curved fiber composite material structural component - on the basis of available prepregs, i.e. dry or optionally pre-impregnated fibers combined to form certain laid scrims - it is a known approach to use sewing techniques to produce individual preform parts with their final shape, i.e. three-dimensional individual preform parts that are dimensionally stable in three-dimensional space. These individual preform parts are sewed to form three-dimensional preforms. The sewing procedure here is three-dimensional. As an alternative, so-called binder preforming is used with which, however, the placement of unidirectional tapes into the flanges is difficult. The object of the invention is to provide a method for the production of a three-dimensionally curved fiber composite material structural component, for example, a former or spar in airplane or helicopter construction, which - with little production effort - makes it possible to bring the unidirectional fibers and the fiber laid scrim into a three-dimensional shape in which the desired fiber orientation in the individual areas is ensured. This object is achieved by a method having the features of claim 1. Preferred embodiments are presented in the dependent claims. The essential aspect of the invention is that - by changing the sewing order, that is to say, by systematically sewing base fiber laid scrims that are adapted to the forces that have to be absorbed by the individual areas of the fiber composite material structural component - first of all, a prefabricated fiber laid scrim strip having fiber laid scrim partial areas of a different orientation is produced in a flat manner, including unidirectional fiber strips and having, for example, fiber orientations in a range from ±45° to ±60°. This prefabricated fiber laid scrim strip is then draped three-dimensionally as a function of the desired contour of the fiber composite material structural component to be produced, so that part of the prefabricated fiber laid scrim strip is angled out of the working plane with respect to another area of the fiber laid scrim strip, preferably curved monoaxially around an axis of curvature that extends preferably perpendicular to the unidirectional fibers and parallel to the tape plane of the unidirectional fibers. In this three-dimensionally draped form, the prefabricated fiber laid scrim strip is sewed onto a support material in order to create a stabilized first sub-fiber laid scrim preform. In airplane construction, when it comes to creating fiber composite material structural components, for example, fiber composite material structural components that form spars, it is especially preferred if the base fiber laid scrim has a fiber orientation in the range from ±30° to ±65°, preferably in the range from ±45° to ±60°, and especially preferably +45°. According to an especially preferred embodiment, the prefabricated fiber laid scrim strip is draped in such a way that the unidirectional 0° fiber laid scrim strip in the sub-fiber laid scrim preform constitutes part of a flange element of a later flexural member cross section of the fiber composite material structural component that is to be produced. Preferably, 0° fiber laid scrim strip is taken here for the production and draping of the prefabricated fiber laid scrim strip, that is to say, this area is placed flat in the first sewing step, and placed so as to correspond to the desired shape in the step in which it is sewed onto a support. The base fiber laid scrim whose fibers have a different orientation is distorted correspondingly, preferably in the plane, so that it follows the shape prescribed by the unidirectional tape. According to an especially preferred embodiment, particularly for configuring a C-spar as the fiber composite material structural component, steps a) through f) are carried out a second time, namely, in order to form at least a second sub-fiber laid scrim preform, whereby the first as well as the second sub-fiber laid scrim preform are essentially L-shaped. The second sub-fiber laid scrim preform is inserted as a second layer into the first sub-fiber laid scrim preform so as to nest with it and these are then joined together by sewing. Here, the sub-fiber laid scrim preforms are preferably inserted into each other so as to nest in that a sub-fiber laid scrim preform is draped so as to overlap with a base strip whose width is reduced in comparison to the other base strip of the other sub-fiber laid scrim preform and is joined by sewing and, hence, the individual base strips preferably overlap at least in areas. In another step, the sub-fiber laid scrim preforms are preferably impregnated together - that is to say, when they have been joined to the fiber laid scrim preform -with a curable resin and the resin is cured. According to a preferred embodiment, the support material can be removed before the impregnation with resin. As an alternative, the support material can likewise be impregnated with resin. During the procedure of sewing the prefabricated fiber laid scrim strip onto a support material in order to produce a three-dimensionally curved fiber laid scrim preform, preferably the prefabricated fiber laid scrim strip, which corresponds to the web strip area, is subjected to an advancing movement and simultaneous rotation, so that, during the sewing procedure, a distortion of the fiber arrangement is achieved, thus obtaining the three-dimensional spatial shape as well as the desired curvature. For this purpose, the sewing procedure can preferably be assisted by using a template in a plane. In the template, the seam lines are drawn that lead to a distortion of the multi-directional laid scrim that, together with the unidirectional laid scrim, forms, for example, the web. Below, the production of a fiber composite material structural component with a fiber laid scrim preform according to the invention will be described with reference to the example of a C-spar. Here, the flange areas of the C-spar are to be made of a unidirectional tape (with so-called 0° fibers), while the web area is made of a base fiber laid scrim or optionally of a woven fabric that can be draped in a plane. The base fiber laid scrim is preferably a ±45° fiber laid scrim, that is to say, a tape material whose fibers run at an angle of +45° or -45° relative to the tape lengthwise direction. Other base fiber laid scrims with other fiber orientations can be used. After the base fiber laid scrim and the unidirectional tape have been cut, the unidirectional tape is positioned on or against the base fiber laid scrim. In this process, the unidirectional fiber laid scrim tape is not necessarily laid on or against the entire base fiber laid scrim but rather it can also extend above only a partial area of this base fiber laid scrim. On the other hand, the unidirectional fiber laid scrim tape can also extend over the entire length of the base fiber laid scrim. Subsequently, the unidirectional fiber laid scrim tape is fixed onto the base fiber laid scrim. This is done over a flat surface, i.e. in a plane without a need for molded parts to orient the unidirectional fiber laid scrim tape and the base fiber laid scrim three-dimensionally with respect to each other. For example, the fiber laid scrim tape can be fixed to the base fiber laid scrim using fixation seams that run crosswise to the fiber direction of the unidirectional fiber laid scrim tape. This gives rise to a flat, prefabricated fiber laid scrim strip that has a flange strip area containing the unidirectional fiber laid scrim tape and a web strip area that is free of the unidirectional fiber laid scrim tape which, in the example, has the ±45° fiber orientation. This combination of fiber laid scrim tape with 0° fibers and fiber laid scrim tape with a fiber orientation adapted to the loads that are anticipated later on is provided in the working plane, for example, the sewing table. For this sewing procedure as well, a template on the table or an automatic control in the plane can prescribe the position of the seams. The tape parts do not have to be distorted in this context. Subsequently, the arrangement with a 0° and ±45° fiber orientation content is draped corresponding to the contour of the spar or former and sewed onto a support material that is sufficiently dimensionally stable. Preferably, the unidirectional tape is angled out of the working plane around an axis that is essentially parallel to the fiber direction of the unidirectional tape in such a way that the flanges of the spar (opposite legs of the C-spars) are formed by the unidirectional tape. In contrast, the web strip area, which is made up of the base fiber laid scrim strip, remains in the working plane, whereby, however, due to the three-dimensional draping of the flange area (without distorting the latter), the fiber arrangement of the base fiber laid scrim is distorted with an orientation in the plane that is not unidirectional. For this purpose, during the draping procedure and the subsequent sewing procedure to a support material, preferably an advancing movement and simultaneous rotation are provided which leads to a distortion of the unidirectional fiber material relative to the base fiber laid scrim strip. This sewing procedure can also be automated or can use flat templates. This L-shaped draped fiber laid scrim strip is draped on a dimensionally stable support material and stabilized by means of a second fixation seam so that a three-dimensionally curved, first sub-fiber laid scrim preform is created that is adapted to the fiber composite material structural component to be produced, namely, the spar, said preform especially being created in an L-shape consisting of a flange and at least part of the shear web. During the sewing to the support material, the fixation seam is created at a transition area between the flange strip area and the web strip area only in the web strip area so that the distortion of the web strip area is fixed in terms of its fiber orientation. The support material serves primarily to fix the distortion of the web strip area so that it can also be provided only in this area. Subsequently, a second sub-fiber laid scrim preform, which is likewise L-shaped and forms a flange and part of the shear web, is produced in the same manner. The two sub-fiber laid scrim preforms are joined together to form a fiber preform in that their individual web areas are at least partially overlapped and inserted into each other so as to nest. This arrangement is fixed by additional seams. The resulting arrangement is subsequently impregnated with a curable resin, whereby it is dimensionally stable due to the sewing procedure as well as due to the impregnation material, so that the desired shape of the fiber composite material structural component is retained even after the resin has cured. Depending on the stability of the sewed arrangement, the support material can also be removed before the impregnation with resin. The method according to the invention with the sewing steps in the working plane and the subsequent upright positioning between unidirectional fiber laid scrim tapes and a flat base fiber laid scrim can also be used for other fiber composite material structural components or spars, for example, I-spars or box spars, whereby then the connection between the unidirectional and the multidirectional fiber laid scrims is made accordingly. During the sewing fixation procedure, preferably the sewing is carried out along a paper plot of the envisaged seam, with the contour being drawn onto said paper plot. In order to guide the unidirectional tape part, the unidirectional tape that is fixed to the web can be guided to the sewing head, so that the draping of the multidirectional laid scrim in the plane takes place automatically. WE CLAIM: 1. A method for the production of a three-dimensionally curved fiber composite material structural component that has a predefined flexural member profile cross section with at least one web area and at least one adjacent flange area with 0° fibers, comprising the following steps: a) providing a flat base fiber laid scrim that can be draped in at least one plane; b) arranging a unidirectional fiber laid scrim tape with 0° fibers on a partial area of the provided fiber laid scrim which lies in the at least one flange area of the fiber composite material structural component to be produced; c) fixing the fiber laid scrim tape on the base fiber laid scrim by sewing using at least one first fixation seam to create a flat prefabricated fiber laid scrim strip that has a flange strip area containing the unidirectional fiber laid scrim tape and a web strip area that is free of the unidirectional fiber laid scrim tape; d) providing the flat prefabricated fiber laid scrim strip in a working plane; e) draping the prefabricated fiber laid scrim strip corresponding to the desired contour of the three-dimensionally curved fiber composite material structural component to be produced, whereby the flange strip area of the fiber laid scrim strip is angled out of the working plane with respect to web strip area and is only curved monoaxially around at least one axis of curvature that extends perpendicular to the 0° fibers and parallel to the tape plane of the unidirectional fiber tape; and the web strip area of the fiber laid scrim strip is draped essentially only in the working plane and, in this process, its fiber arrangement is distorted; and f) sewing the prefabricated fiber laid scrim strip onto a support material that can be draped in at least one plane by means of at least one second fixation seam that is created at a transition area between the flange strip area and the web strip area only in the web strip area so that a stabilized three- dimensionally curved first sub-fiber laid scrim preform is created that is adapted to the fiber composite material structural component to be produced. 2. The method according to claim 1, characterized in that the base fiber laid scrim created in step a) has a fiber orientation in the range from ±30° to ±65°, especially in the range from ±45° to ±60°, and especially preferably ±45°. 3. The method according to claim 1 or 2, characterized in that in step e), the 0° fiber laid scrim strip serves as a reference for the draping and fixing of the prefabricated fiber laid scrim strip. 4. The method according to any of the preceding claims, characterized in that steps a) to f) are carried out once again in order to form a second sub-fiber laid scrim preform and the sub-fiber laid scrim preform is inserted as a second layer into the first sub-fiber laid scrim preform so as to nest with it and these are then joined together by sewing. 5. The method according to claim 4, characterized in that the first sub-fiber laid scrim preform and the second sub-fiber laid scrim preform are each L-shaped and the web strip areas of the first sub-fiber laid scrim preform and of the second sub-fiber laid scrim preform that are free of the unidirectional fiber laid scrim tape are joined to each other to form a fiber preform in such a way that the fiber •preform is C-shaped. 6. The method according to any of the preceding claims, characterized in that, in a step g), the sub-fiber laid scrim preform or the fiber preform are impregnated with a curable resin and the resin is cured. 7. The method according to claim 6, characterized in that, before step g), the support material is removed from the fiber preform and/or from the sub-fiber laid scrim preform. 8. The method according to claim 6, characterized in that, in step g), the support material is impregnated with resin together with the sub-fiber laid scrim preform and/or with the fiber preform. ABSTRACT The invention relates to a method for production of a three-dimensional curved fibre composite material structural component, having a defined flexible girder profile cross-section with at least one web region and at least one flange region connected thereto with 0°-fibres, comprising the following steps: a) preparation of a planar base non-woven fibre which may be laid in at least one plane, b) arrangement of a uni¬directional non-woven fibre strip with 0°-fibres on a part section of the prepared non-woven fibre, laying the at least one flange region of the fibre composite material structural component to be produced, c) fixing the non-woven fibre strip to the base non-woven fibre by stitching with at least one first fixing seam to form a planar pre-made-up non-woven fibre strip, provided with a flange strip region containing the uni-directional non-woven fibre strip and a web strip region with no uni-directional non-woven fibre strip, d) preparation of the planar pre-made-up non-woven fibre strip in a working plane, e) laying the pre-made-up non-woven fibre strip according to the desired shape of the three-dimensional curved fibre composite material structural component to be produced, the flange strip region being bent out of the working plane with relation to the web strip region about a single axis around at least one bending axis, running perpendicular to the 0°-fibres and parallel to the strip plane of the uni-directional non-woven fibre strip and the web strip region of the non-woven fibre strip laid essentially only in the working plane wherein the fibre arrangement is deformed and f) stitching of the pre-made-up non-woven fibre strip on a support material laid in at least one plane by means of at least one second fixing seam, applied to a transition region between the flange strip region and the web strip region only in the web strip region such that a stabilised three-dimensionally curved first sub-non-woven fibre blank corresponding to the fibre composite material structure component is formed. To The Controller of Patent The Patent Office Mumbai

Documents:

80-mumnp-2008-abstract.doc

80-mumnp-2008-abstract.pdf

80-MUMNP-2008-CANCELLED PAGES(1-8-2011).pdf

80-MUMNP-2008-CLAIMS(AMENDED)-(1-8-2011).pdf

80-mumnp-2008-claims.doc

80-mumnp-2008-claims.pdf

80-MUMNP-2008-CORRESPONDENCE(1-8-2011).pdf

80-mumnp-2008-correspondence(21-4-2008).pdf

80-MUMNP-2008-CORRESPONDENCE(22-7-2008).pdf

80-mumnp-2008-correspondence-others.pdf

80-mumnp-2008-correspondence-received.pdf

80-mumnp-2008-description (complete).pdf

80-MUMNP-2008-EP DOCUMENT(1-8-2011).pdf

80-MUMNP-2008-FORM 3(1-8-2011).pdf

80-mumnp-2008-form-1.pdf

80-mumnp-2008-form-18.pdf

80-mumnp-2008-form-2.doc

80-mumnp-2008-form-2.pdf

80-mumnp-2008-form-3.pdf

80-mumnp-2008-form-5.pdf

80-mumnp-2008-form-pct-ib-301.pdf

80-mumnp-2008-form-pct-ib-304.pdf

80-mumnp-2008-form-pct-ib-306.pdf

80-MUMNP-2008-PETITION UNDER RULE 137(1-8-2011).pdf

80-mumnp-2008-power of authority(21-4-2008).pdf

80-MUMNP-2008-REPLY TO EXAMINATION REPORT(1-8-2011).pdf

80-mumnp-2008-wo international publication report(16-1-2008).pdf