FR2591618A1 - CARBON FIBER TISSUE TAPE, AND METHOD FOR IMPLEMENTING THE SAME - Google Patents

Abstract

The invention relates to a carbon fiber fabric tape, made of warp and weft yarns, for the production of protective layers for parts, or for the production of parts, which are subjected to a medium having a high temperature and high flow rate, in particular for the manufacture of rocket engine nozzles with short combustion duration. The weft threads 3 are in the form of single U-shaped threads, and their straight segments (the branches of the U) are arranged parallel to each other, and transversely to the warp threads 2 arranged in the direction 4 of the length of the strip. The free ends of the weft threads 3 are all on the same side of the strip, and the free ends of the weft threads protrude from the woven part of the strip by a length at least equal to the width 5 thereof. (CF DRAWING IN BOPI)

Description

CARBON FIBER FABRIC TAPE, AND METHOD

TO IMPLEMENT IT

  The invention relates to a carbon fiber fabric tape, consisting of warp and weft threads, for the production of protective layers for parts, or for the production of parts, which are subjected to a medium having a

  high temperature and flow velocity, especially

  special for the manufacture of nozzle coating

  rocket engines with short combustion time. Linen-

  The invention also relates to a method of manufacturing.

  parts, wholly or partly of a

  carbon fiber fabric tape as defined above

  above and an appropriate matrix, in particular sta-

  heat (eg phenolic resin), on

  a negative form (for example a nucleus), or by recou-

  of a positive form (eg a supernatural body)

  Harbor). During an aerial or space flight, there is frequently the problem of simultaneously subjecting the surfaces of the object to high temperatures and high flow velocities. Examples are propellers of all kinds, but also

  spacecraft when they enter the atmosphere.

  In the case where the thermal and mechanical stresses linked to the flow extend over a long period of time, or appear several times at intervals, the relevant surface of the object is made and protected in such a way that it does not suffer. no damage,

  or that it suffers only deteriorations

  paging very slowly. For example, long-life rocket motor nozzles are generally fluid-cooled, and made of mostly high-melting materials, mostly metal. If the stresses only last for a short time, as for example in rocket nozzles with a short combustion time, one can also take into consideration a greater thermal and mechanical stress (by combustion and by erosion). In

  such cases, it is advantageous to use

  fiber-reinforced plastics, because of their favorable strength / weight ratios, and because of their

  the simplicity and low cost of their manufacture.

  A combination of materials usual for this until recently was that of phenolic resin and asbestos fibers; but for the future, we must not use asbestos because of its harmful properties for the

  health. Carbon fibers, among others, have

  used alternative materials, in particular

  because of their good mechanical and thermal properties.

  If, for example, a carbon fiber and phenolic resin fabric nozzle body is produced, according to the negative-form deposition method, in the usual manner for other parts, so that the fabric layer becomes located parallel to the surface of the negative form (flow contour), it is then expected, during operation, that,

  as a result of thermal deterioration and

  mechanics, entire layers of fabric are

  slow and expelled, which can lead to very

  quickly to the destruction of the nozzle.

  DE-AS 12 03 646 discloses a layered fiber-reinforced plastic wall for flying machines, rocket engines, etc., which largely avoids such processes. wear. A strip of fabric and fiberglass, impressed

  resin, is then wound helically on a

  negative, so that the transverse sections

  Dirty strips of the strip overlap in the manner of roof tiles, and form an angle of about 20 with the direction of flow, the edges directed downstream of the fabric web forming the flow outline. Of course, the expulsion of entire layers of fabric is thereby prevented with certainty, but it may be that threads of the fabric, still arranged transversely to the flow, are removed from the edges of the fabric band forming the contour of the flow; certainly, the wear progresses so more slowly,

but nevertheless with constancy.

  The object of the invention is therefore to develop a web of fabric, as well as a method for carrying it out, with a view to a net increase and

  important part of the useful life of the parts.

  According to the invention, this object is

  dyed by means of a carbon fiber fabric strip of the type defined above, characterized in that the weft threads are in the form of single U-shaped yarns, that their straight segments (the U-branches) are arranged parallel to each other. one against another,

  and transversely to the warp threads

  laid in the direction of the length of the strip, that the free ends of the weft yarns are all on the same side of the strip, and that the free ends of the weft yarns protrude from the woven portion of the strip

  of a length at least equal to the width of the latter.

  According to the invention, the object cited above

  The above is also achieved by a method of the type

  defined above, characterized in that the web of

  The carbon fiber is disposed in a manner known per se substantially transverse to the direction of flow so that the successive cross-sections of strips follow one another in the direction of the flow. covering tiles with a roof and forming an acute angle with the flow outline, that the free ends

  superimposed weft threads, in the trans-

  versales, are oriented downstream of the

  together with the matrix, form the flow contour, with overlapping of the warp threads each arranged downstream of the flow,

  and that in the case of manufacture on a

  it may be necessary to carry out a subsequent coating using a fiber composite material,

  very solid, especially from the mechanical point of view.

  In this respect, it should be pointed out that the process having the above characteristics is suitable not only for making windings on symmetrical parts of revolution, but also for

  the manufacture of plate-shaped parts by

  series of insulated fabric webs next to one another, for example for the production of control nozzle segments, guide profiles

  flow, or scales of heat shields.

  A preferred embodiment of the process having the characteristics mentioned above

  is a method of manufacturing a hollow body, symmetrically

  virtually rotates, having an internal flow contour, on a core, in particular

  for the manufacture of a nozzle body of a motor-

  rocket, characterized in that the present core

  a main area for the formation of the listening contour

  - 5 - the hollow body, as well as, in extension of the flow contour, an input domain and an output domain, the length of these last two domains in the direction of the flow corresponding each approximately to the total width of the fabric strip in

  carbon fibers (including the weft yarns

  edge), that the core, from the domain of entry to the domain

  outlet (in the direction of flow) is

  covered with the band of carbon fiber fabric which forms a helix, which is carried out in the main field, a subsequent recovery with a very strong winding structure based on carbon fibers (fabric, roving, etc.). , carbon fibers), and after the hardening of the workpiece (hollow body) and the removal of the core, the wraps of tissue bands protruding

  the main domain (field of entry and field of

tie) are eliminated.

  Another preferred embodiment of the process of the present invention is a process presenting the

  characteristics mentioned above, for the recovery of

  positive form, in particular for the recou-

  metal protective structures of a motor-driven nozzle, characterized in that the carbon-fiber fabric strip is deposited on the positive form (protective metal structure), helically, in the opposite direction to that of the flow. In what follows, the invention is illustrated

  in more detail by the exemplary embodiments

on the accompanying drawings.

  FIG. 1 represents a plan view of a piece of the fabric strip according to the invention in

carbon fibers.

  FIG. 2 represents a sectional view, in the length direction, through the upper half of a rotationally symmetrical hollow body with a shape

negative (core).

  Fig. 3 is a lengthwise sectional view through the nozzle portion of a solid propellant rocket engine. As can be seen in FIG. 1, the weft threads 3 of the fabric band 1 made of carbon fibers,

  which are U-shaped insulated wires, are woven

  versally in the warp yarns 2 arranged in the direction 4 of the length of the strip. It will be understood here that, according to the weaving method (in fabric, cross-fabric, ect.), The weft threads 3, at the point of intersection with

  the warp threads 2 are above or below

  under warp threads, according to a fixed armor. Thanks to the free ends, overflowing widely, warp threads 3, the width 5 of the woven part of the band

  is much smaller than the total width of the ban-

  of fabric 1 made of carbon fibers. For fabric bands according to the state of the art, it is however usual to weave with the warp threads

  continuous pattern, so that it forms

  the width of the woven part corresponding to

to the width of the band.

  In Figure 2, it can be seen why the special structure of the carbon fiber fabric web 1 positively influences the strength of the

  rooms. For the manufacture of a hollow body 12 with symmetry

  trie of revolution, is coated with the carbon fiber web 1, so as to form a helix, a core 8, from the input domain 10 through the main domain 9 to the output domain 11, in the direction of flow 6. The outer side of the core 8, which forms the flow contour 7, is then covered with a separating means, and the carbon fiber cloth strip 1 is impregnated, before or during 7- the deposition of the matrix (for example phenolic resin) not shown. The input domain 10 serves to move the layout of the cross sections of the

  band, parallel to the flow contour in the first

  first windings, at the desired biased position, imitating the tiles of a roof, in the main domain 9. The output domain 11 serves as support for the wires

  of weft 3, not necessary, of the last few

  bearings of the fabric band 1 made of carbon fibers.

  In the main domain 9, we can clearly recon-

  arise that the flow contour 7, apart from the matrix, is exclusively formed by the warp son 3 arranged at an acute angle relative to him. The weft threads 3 cover the warp threads 2 and protect them against thermal attack and

  mechanical due to flow. In operation

  the matrix br is in the area of the surface (contour of the flow 7), but its residues form, together with the weft threads 3 firmly anchored in the outer layers of the part, a layer well

  resistant material for the contiguous material

  This also contributes to the flow-friendly arrangement of weft threads 3 arranged approximately in the direction 6 of the flow. In order to further increase the strength of the part, it is possible to have in the main area 9,

  on the turns of the fabric band 1 made of

  bone, a winding structure 13, with high resistance

  made from carbon fibers (fabric, roving, etc.).

  After the hardening of the hollow body 12 and the withdrawal

  of core 8, the main domain 9 is separated from the

  protruding strands of fabric, which does not

  not to the piece, entry and exit domains

  and 11. For reasons of simplicity, we can not

  FIG. 2 shows that the structure of a hollow body

- 8 -

  cylindrical of revolution, and the main domain 9 has been strongly shortened on this representation. This method of operation is particularly suitable however for the manufacture of a complete Laval nozzle body, the core 8 to be cut in the

  region of the neck of the nozzle (that where the trans-

  versale is the narrowest) perpendicular to its

  axis so that it can be removed from the hardened part.

  It should also be noted that, depending on the thermal and mechanical requirements, it is possible, in the field of warp yarns 2, to incorporate additional fibrous reinforcing materials (roving, etc.) between the windings of the fabric web 1 into carbon fibers. It is then only necessary to ensure that these fibrous reinforcing materials, as well as the warp threads 2, are completely covered by the weft threads 3. FIG. 3 presents another possibility.

  of use of the fabric web 1 of carbon fibers

  ne, namely for the recovery of the metal structure

  protection plate 16 of the nozzle 15 of a rocket engine

  14 solid propellant of the known type. In the propul-

  According to the state of the art, the protective metal structure is fixed in the area of the neck of the nozzle with the aid of a thick graphite ring.

  and in the convergent and divergent parts is de-

  laid with asbestos fiber and phenolic resin

  lic. According to FIG. 3, the coating 17 of the structure

  metal protection 16 is formed in the convergent and divergent portions of the nozzle 15,

  winding of the fabric web 1 of

  bone, arranged in the manner of the tiles of a roof, in a manner comparable to that shown in Figure 2, the deposit on the metal structure 16 being however made in the form of a helix, in a reverse direction to that of the flow, and -9-

  the matrix sticking the strip of tissue undetachably

  to the protective structure (positive form). The other constructional features of the solid propellant rocket engine 14, such as graphite ring 18, fuel arrangement 19, etc., are conserved without modifications, so that, with regard to the Figure 3, it can be seen that the invention resides first and foremost in the advantageous replacement

  asbestos which is a material that is harmful to your health.

  As already mentioned in the introduction of the

  description, there are still many other pos-

  usability for the web of fabric according to the invention and for the method of implementation relating thereto (heat shield scale, segment of

  removable nozzle, flow profile, etc.), the structure

  However, parts are still based on the same

  staging, like roof tiles, of

  cross sections of the fabric web, with the threads

  weft arranged on the flow side.

25916i8-

- 10 -

Claims (4)

  1. Carbon fiber fabric tape, consis-   formed of warp and weft threads, for the production of protective layers for workpieces, or for the manufacture of workpieces, which are subjected to a medium having a high temperature and a fast flow rate, in particular for manufacture of rocket engine nozzle liner with short combustion time, characterized in that the weft yarns (3) are in the form of single U-shaped yarns, whereas their straight segments (the U-branches) are arranged in parallel with each other. with respect to each other, and transversely to the warp threads (2)   arranged in the direction (4) of the length of the bank.   the free ends of the weft yarns (3) are all on the same side of the strip, and the free ends of the weft yarns project from the woven part of the strip by at least a length equal to the width (5) thereof.   2. Process for the manufacture of parts,   totally or partially killed from a carbon fiber fabric ribbon according to claim 1 and a suitable matrix, in particular heat stable (eg phenolic resin), to a negative form (eg a core), or by covering a positive shape (for example a support body), characterized in that the carbon fiber web (1) is disposed, in a manner known per se, substantially transversely to the   direction of flow, so that the   successive cross-sections of strips succeed one another in the direction of the flow, overlapping in the manner of the tiles of a roof and forming an acute angle with the flow contour, that the ends   free superposed weft threads (3), in the sec-   transverse banding, are oriented towards 25916i8 - 11 -   downstream of the flow and form, together with the matrix, the flow contour, with overlap of the warp threads (2) arranged each time to   downstream of the flow, and that in the case of the manufacturer   cation on a negative form, it may be necessary to carry out a subsequent coating with a very strong fiber composite material, in particular from the point mechanical view.   3. Process according to claim 2,   for the manufacture of a hollow body, with practically symmetrical   revolution, with an inner contour   flow, on a nucleus, especially for the   of a nozzle body of a rocket engine, which is   characterized in that the core (8) has a primary domain   cipal (9) for the formation of the flow contour (7) of the hollow body (12), and, as an extension of the flow contour (7), an input domain (10) and   an output domain (11), the length of these two last   areas (10, 11) in the direction of the   (6) each corresponding approximately to the total width of the carbon fiber web (1) (including weft yarns which overflow),   core (8), from the input domain (10) to the output domain   (11) (in the direction of flow), is   green of the fabric web (1) made of carbon fibers which forms a helix, which is made in the field   (9), a subsequent recovery with a structure   very strong coil winding (13) based on carbon fibers (fabric, roving, etc., of carbon fibers), and after the hardening of the piece (hollow body 12), and removal of the core (8), the windings of webs extending beyond the main domain (9) (domain   input and output domain (10, 11)) are eliminated. - 12 -   4. Process according to claim 2,   for the recovery of a positive form, in particular   bind for the recovery of metal structures from   protection of a rocket engine nozzle, a method   characterized in that the carbon fiber web (1) is deposited on the positive shape (metal structure (16) of protection), helically, in the   reverse direction of that of the flow.