Support tooling for winding a fiber texture, a method of fabricating a fiber texture, and a method of fabricating a fiber preform for a body of revolution

A support tooling includes a mandrel presenting an outside surface onto which a fiber texture in the form of a strip is to be wound. The support tooling also has an extension including a flexible strip extending over a determined length between a first end fastened to the mandrel of the support tooling and a second end that is free and that has an attachment system suitable for holding the end of the fiber texture in the form of a strip for winding.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to French Patent Application No. 1558254, filed Sep. 7, 2015, the entire content of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to making composite material parts that are bodies of revolution, and more particularly to making and winding fiber textures that are to constitute the fiber reinforcement of such parts.

The field of application of the invention is more particularly making parts that are bodies of revolution out of structural composite material, i.e. structural parts comprising fiber reinforcement densified by a matrix. Composite materials enable parts to be made presenting overall weight that is smaller than the same parts would have if they were made out of metal.

For a part that constitutes a body of revolution, such as for example an aeroengine casing, the fiber preform that is to form the reinforcement of the part is made from a fiber texture that is wound on support tooling.

More precisely, and as shown inFIG. 1, a fiber texture10in the form of a strip is woven as a single piece by three-dimensional (3D) or multilayer weaving between a plurality of layers of warp yarns. The 3D or multilayer weaving of the fiber texture10is performed in a loom20of Jacquard type, with weaving consisting in inserting weft yarns12so as to create a pattern between warp yarns11. At the outlet from the loom20, the fiber texture10is wound on support tooling30comprising a mandrel31presenting an outside surface31aonto which the fiber texture10is wound.

A fiber preform is then made by winding the fiber texture10under tension onto a mold tooling. As shown inFIG. 2, intermediate conveyor rollers40and50are used for making the tension uniform across the width of the fiber texture10while it is being wound under tension onto a mold tooling60, the texture10being unwound from the support tooling30. The mold tooling60comprises a mandrel61having an outside surface onto which the fiber texture10is wound under tension, said outside surface presenting a shape that corresponds to the shape of the composite material part that is to be made. The fiber texture10is held on the mandrel61of the mold tooling60by means of a shoe62that is removed between turns in order to be able to wind the following turn.

At the end of winding, i.e. after a plurality of turns of fiber texture10have been made on the mold tooling60so as to form a fiber preform80, a shoe62is put into position once more in order to hold the preform80in place and prevent it from unwinding while it is being cut by a blade70as shown inFIG. 3.

Once the fiber preform80has been made in this way, injection sectors (not shown inFIG. 3) are put into position around the mold tooling60in order to impregnate the preform with a resin that is a precursor of the matrix.

Winding in that way presents drawbacks. Specifically, using intermediate conveyor rollers makes it necessary to provide an extra length of fiber texture, since the fiber texture needs to be held permanently under tension until the end of being wound on the mold tooling. As shown inFIG. 3, at the end of winding an extra length15of the fiber texture10is present between the support tooling30and the mold tooling60for the purpose of keeping the fiber texture10under tension. The extra length15is woven in continuity with the texture10that is used for making the preform80. Since the beginning of weaving the fiber texture10corresponds to the end of winding, the extra length15is woven at the beginning of the fiber texture10and is fastened to the support tooling30.

An extra length is thus associated with each fiber texture, and it is eliminated when the preform60is cut. The extra length15is then lost since it cannot be reused. This loss of material increases the cost of fabricating the preform and the cost of the resulting part made of composite material.

OBJECT AND SUMMARY OF THE INVENTION

It is therefore desirable to be able to have a way of making fiber preforms by winding that does not present the above-mentioned drawbacks.

For this purpose, the invention proposes support tooling comprising a mandrel presenting an outside surface onto which a fiber texture in the form of a strip is to be wound, the tooling further comprising an extension in the form of a flexible strip extending over a determined length between a first end fastened to the mandrel of the support tooling and a second end that is free and that includes an attachment system suitable for holding the end of a fiber texture in the form of a strip that is to be wound. The attachment system comprises two jaws connected together by a hinge in such a manner as to form a clamp that is movable between an open position in which the jaws are spaced apart from each other and a closed position in which the jaws are clamped relative to each other. The attachment system further comprises one or more intermediate clamping elements present between the two jaws. Each intermediate clamping element may present surfaces that are rough.

By means of the extension of the support tooling of the invention, the extra length of fiber texture that used to be required at the end of winding for maintaining the tension between the support tooling and the mold tooling and that was sacrificed when cutting the preform, is no longer required, since it is replaced by the extension. Also, the extension can be reused for making new fiber preforms.

In an aspect of the support tooling of the invention, the flexible strip of the extension is constituted by a strip of woven yarns made of a material selected from at least one of the following materials: poly(p-phenyleneterephthalamide) (PPD-T) better known under the name Kevlar®, intermediate modulus carbon, poly(imino-1,3-phenyleneiminocarbonyl-1,3-phenylenecarbonyl) better known under the name Nomex®, and glass. One of the jaws may also include spikes on its face facing the other jaw in order to improve retention of the fiber texture.

The invention also provides a method of making a fiber texture for reinforcing a part in the form of a body of revolution and made out of composite material, the method comprising using three-dimensional or multilayer weaving between a plurality of layers of yarns to form a strip of fiber texture as a single piece, and winding said texture onto support tooling comprising a mandrel having an outside surface onto which the fiber texture is wound, the support tooling also comprising an extension in the form of a flexible strip extending over a determined length between a first end fastened to the mandrel of the support tooling and a second end that is free and that has an attachment system for holding one end of the fiber texture in the form of a strip while it is being wound onto the support tooling. The attachment system comprises two jaws connected together by a hinge, with the end of the fiber texture being held between the two jaws while the fiber texture is being wound onto the support tooling. The attachment system further comprises one or more intermediate clamping elements present between the two jaws, and the end of the fiber texture comprises a distal portion in which at least some of the yarn layers are woven without interlinking with the other yarn layers of said texture, each layer woven without interlinking being held between a jaw and an intermediate clamping element or between two intermediate clamping elements of the attachment system.

The invention also provides a method of making a fiber preform in the form of a body of revolution, the method comprising making a fiber texture using the method of the invention for making a fiber texture, and the method of making a fiber preform in the form of a body of revolution comprising winding said fiber texture under tension onto the outside surface of a mandrel of mold tooling so as to obtain a fiber preform in the form of a body of revolution.

DETAILED DESCRIPTION OF EMBODIMENTS

The invention applies in general manner to making composite material parts in the form of bodies of revolution, such as aeroengine casings, e.g. such as fan casings, the parts being obtained by making fiber preforms in the form of bodies of revolution by winding and then densifying the preforms with a matrix. These parts such as aeroengine casings are of large dimensions, and in various ranges of such turbine engines for propelling airplanes, casings may have a diameter of the order of one meter up to three meters.

In accordance with the invention and as described below in detail, the present invention proposes using support tooling fitted with an extension enabling a fiber texture to be wound under tension while it is being shaped and without losing material.

The method of making a fiber texture of the invention begins by forming a fiber texture in the form of a strip that is subsequently wound onto a support tooling. In this example, the fiber texture is to form a fiber preform for an aeroengine casing.

The fiber texture is obtained by three-dimensional (3D) or multilayer weaving performed in known manner by means of a Jacquard type loom having a bundle of warp yarns or strands arranged in a plurality of layers, the warp yarns being interlinked by weft yarns. In the presently described example, the multilayer weaving is weaving with an “interlock” weave. The term “interlock” weave is used herein to mean a weave in which each layer of weft yarns interlinks a plurality of layers of warp yarns, with all of the yarns in a given weft column having the same movement in the weave plane. Other known types of multilayer weaving could be used, in particular such as those described in document WO 2006/136755, the content of which is incorporated herein by way of reference.

Particularly but not exclusively, the fiber texture of the invention is woven from yarns such as yarns of carbon fibers, of ceramic fibers such as silicon carbide fibers, or indeed of glass fibers.

FIG. 4shows support tooling100in accordance with an embodiment of the invention that comprises a mandrel110presenting an outside surface111onto which a fiber texture in the form of a strip is to be wound. The support tooling100also has an extension120comprising a flexible strip121extending over a determined length between a first end1210fastened to the mandrel110of the support tooling and a second end1220that is free and that has an attachment system130suitable for holding the end of a fiber texture in the form of a strip for winding.

The end of the flexible strip is fastened to the support tooling, preferably using a fastener system that does not give rise to any extra thickness in the surface of the mandrel of the support tooling. In the presently-described embodiment and as shown inFIG. 5, the mandrel110presents a recess112in its outside surface111suitable for receiving a fastener device150for fastening the first end1210of the flexible strip121and for incorporating it in the shape of the mandrel without extra thickness. In this example, the fastener device150is constituted by a fastener plate151presenting a shape that is complementary to the shape of the recess112, together with screw fasteners152, the plate151also including a plurality of orifices1510for passing the fasteners152. The end1210of the flexible strip121has a plurality of orifices1211that are reinforced by eyelets1212, the positions of the orifices1011coinciding with the positions of the orifices1510formed in the fastener plate151. The end1210of the strip121of the extension120is held between the plate151and the bottom of the recess112by tightening the fasteners152in the orifices1120, which orifices are provided with tapping that co-operates with the threads of the fasteners152(not shown inFIG. 5).

The person skilled in the art will have no difficulty in envisaging other embodiments of the device for fastening the end of the strip on the mandrel of the support tooling.

The strip121of the extension120may be made of any flexible material presenting a very small elongation percentage and withstanding the tension forces that are applied while the fiber texture is being wound on the mold tooling. By way of nonlimiting example, the strip120may be constituted by a strip obtained by weaving yarns made of any one of the following materials: poly(p-phenyleneterephthalamide) (PPD-T) better known under the name Kevlar®, intermediate modulus carbon, poly(imino-1,3-phenyleneiminocarbonyl-1,3-phenylenecarbonyl) better known under the name Nomex®, and glass.

In the presently-described embodiment and as shown inFIG. 6, the attachment system130comprises two jaws131and132that are connected together by a hinge133secured to the end1211of the strip121. The jaws131and132thus form a clamp that is movable between an open position in which the jaws131and132are spaced apart from each other (FIG. 6) enabling an end of a fiber texture for holding to be inserted, and a closed position (FIG. 7) in which the jaws131and132are clamped against each other, e.g. by means of screws (not shown inFIG. 7) so as to hold captive and retain the end of the fiber texture that is to be wound.

In order to prevent the texture sliding between the two jaws131and132, one of the two jaws, in this example the jaw131, may be provided with spikes1310, while the other jaw, in this example the jaw132, may include recesses1320receiving the tips of the spikes1310when the two jaws are clamped together. If the jaws131and132are of large dimensions, they are preferably curved in shape with curvature corresponding to the curvature of the mandrel of the support tooling, as shown inFIG. 6.

There follows a description of a method of making a fiber preform in the form of a body of revolution by winding a fiber texture under tension onto mold tooling.

FIGS. 7 and 8show a fiber preform280being made from a fiber texture210woven using 3D or multilayer weaving. As described above with reference toFIGS. 2 and 3, the fiber preform is made by winding the fiber texture210under tension onto mold tooling260, with intermediate conveyor rollers240and250being used to make the tension uniform over the width of the fiber texture while it is being wound under tension onto the mold tooling260, the fiber texture being unwound from the support tooling100(FIG. 7). The mold tooling260comprises a mandrel261onto the outside surface of which the fiber texture is wound under tension, said outside surface presenting a shape that corresponds to the shape of the composite material part that is to be made. At the end of winding, and as shown inFIG. 8, i.e. after a plurality of turns of fiber texture have been laid on the mold tooling260so as to form a fiber preform280, a shoe262is put into position in order to hold the preform280in place and prevent it from unwinding while it is being cut by a blade270

The cut is made immediately in front of the free ends of the jaws131and132of the system130for attaching the extension120, thus making it possible to avoid having losses of material in the fiber structure210used for making the preform280. Specifically, the extra length of fiber texture that used to be required at the end of winding for maintaining tension between the support tooling, and the mold tooling and that was sacrificed when cutting the preform, is replaced in this example by the extension120. Also, the extension120can be reused for making new fiber preforms.

FIG. 9shows a variant embodiment of the extension attachment system of the invention. InFIG. 9, an extension320has an attachment system330that differs from the above-described attachment system130in that in addition to the two jaws331and332it further includes intermediate clamping elements333,334, and335that are present between the jaws331and332. The jaws331and332, and also the intermediate clamping elements333,334, and335are connected together by a hinge336that is secured to the end3211of the strip321. The remainder of the extension320is identical to the above-described extension120.

The use of intermediate clamping elements in the attachment system330improves retention of a fiber texture and limits relative sliding between the warp strands or yarns by holding independent portions or plies of the texture captive between a jaw and an intermediate clamping element or between two intermediate clamping elements of the attachment system. For this purpose, and as shown inFIG. 10, a fiber texture310, woven using four layers of warp yarns C1, C2, C3and C4together with weft yarns T, includes, at its end that is to be held by the attachment system330, a portion316in which each of the four layers of warp yarns C1to C4is woven with a two-dimensional (2D) weave, e.g. such as a plain weave or a satin weave, so as to form four independent plies or layers311,312,313, and314, i.e. plies or layers that are not interlinked by the weft yarns T. The remainder of the fiber texture310is constituted by a portion315that is woven with a three-dimensional or multilayer weave in which at least some of the weft yarns T interlink the layers of warp yarns.

As shown inFIGS. 9 and 11, the plies311,312,313, and314are placed respectively between the jaw332and the intermediate clamping element335, between the intermediate clamping elements335and334, between the intermediate clamping elements334and333, and between the intermediate clamping element333and the jaw331. In this example, the intermediate clamping elements333,334, and335include perforations for passing spikes3310. Also, the intermediate clamping elements333,334, and335preferably present surfaces that are rough, thereby increasing the force with which the plies are held.