JPS6028654B2 - Composite material with reinforced structure and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite material having a three-dimensional reinforced structure and a method for manufacturing the same, and more particularly, to a composite material having a three-dimensional reinforced structure and a method for manufacturing the same. This invention relates to composite materials and manufacturing methods for use in structural materials that are subject to stress.

In engines and the like, areas that experience the highest temperatures, such as the nozzle near the throat or jet vip, and parts just before the converging tilt cone, must be made of expensive refractory materials that can withstand the high stresses caused by heat.

Very naturally, carbon is chosen as the substrate because of its very high sublimation temperature and low density.

However, the mechanical and physical properties of carbon, particularly its coefficient of expansion and coefficient of thermal conductivity, vary considerably depending on the shape given to carbon. This has led to the idea of reinforcing structures with reinforcements made of carbon with high mechanical properties, with the main aim of obtaining reinforcements that eliminate areas of reduced resistance that could potentially break. Reinforcement structures obtained by layering unidirectional elements or tissues that need to be bonded without delamination are proposed,
A structure was provided with a reinforcement consisting of three linear filaments crossed at right angles.

However, this structure has a number of drawbacks.

In fact, the spaces created in the reinforcement by the three intersecting edges are in the form of parallelepipeds with dimensions equal to the dimensions of the filament used, and are actually separated from each other, creating a blockage. Although the volume occupied by these spaces varies depending on the cross section of the filament used, it is 25% to 40% of the total volume of the reinforcing section, and it is an obstacle to making the reinforcing section compact. When coating reinforcement parts, this coating can be applied either by concentrating liquid resin and polymerizing and pyrolyzing it, or by gradual penetration, for example by depositing pyrolytic carbon obtained by decomposing hydrocarbon gas on the inner surface. These drawbacks become apparent when the process is carried out by

In the case of this impregnation, pyrolysis is generally achieved by a volume reduction of 50% or more of the resin. In the case of dimensionally stable reinforcements, this volume reduction can lead to cracking of the coating and/or an inability to bond the coating to the fibers. With conventional reinforcements, these drawbacks thus arise, on the one hand, from the volume occupied by the space, and on the other hand, the isolation of the space is promoted. Coating by penetration of gaseous bodies does not result in commercial quality composite structures.

This is because gas infiltration causes premature blockage of a large space, leaving only a communicating passage with a cross-sectional area of 4. An object of the present invention is to provide a composite material having a novel reinforcing structure that has better mechanical properties and can be used in various fields in order to eliminate the above-mentioned drawbacks.

According to the present invention, the three-dimensional reinforcement structure includes four intersecting juxtaposition layers, the reinforcement portion of which is composed of spaced juxtaposed linear filaments with polygonal or circular cross-sections; The layers are arranged alternately in adjacent parallel planes, and the remaining two juxtaposed layers are similarly arranged but in another parallel plane relative to the previous parallel plane. The elements of each juxtaposed layer are attached to adjacent parallel juxtaposed layer elements of another juxtaposed layer. The composite material having the reinforced structure thus obtained has the following effects.

Firstly, the reinforcing structure of the invention has a high reinforcement ratio, ie a high proportion of the volume of the reinforcing elements to the volume of the synthetic material. Second, it has interspaced spaces over a significant area of the reinforcement structure, allowing the densification material to reach the center of the reinforcement structure. moreover,
The four-way structure has high mechanical properties.

For example, a conventional three-way structure with mutually orthogonal elements is a juxtaposition in which elements oriented along two of the directions are perpendicular to elements oriented along a third direction. The formation of layers allows thinning of the reinforcing structure, ie separation of juxtaposed layers of elements from each other along the third direction. However, in the present invention, since the element juxtaposed layer formed by the elements forming one group oriented in two directions is tightly combined with the elements forming the other two groups oriented in different directions, the above-mentioned Separation is impossible. Preferably, the elements included in each element juxtaposition layer are each oriented perpendicularly to the four faces of the regular tetrahedron, and the elements of two adjacent element juxtaposition layers have a hexagonal cross section and are arranged in the shape of the fifth figure of a die. It is a single structure arranged in the form of a completely isotropic and compact reinforcement with a significantly smaller spatial volume than the prior art.

This allows the reinforcing portion to be cut into pieces of complex shape that exhibit uniform properties. According to another aspect of the invention, a method of forming a structure of the type described above comprises aligning linear elements having polygonal or circular cross-sections in parallel to provide first and second reinforcing surfaces alternately and reciprocally. , and in this case, the first
The elements of the reinforcing surface and the elements of the second reinforcing surface are non-parallel, and by arranging elements similar to the elements of the first and second reinforcing surfaces parallel to each other, the elements of the third and fourth reinforcing surfaces are Inserting the elements of the third and fourth reinforcing surfaces between the elements of the first and second reinforcing surfaces so that they are non-parallel to each other and the third reinforcing surfaces and the fourth reinforcing surfaces are parallel and alternate. , and impregnating or coating a reinforcing structure consisting of a first blank and a fourth reinforcing surface with a densifying material.

Hereinafter, the present invention will be described by way of preferred embodiments with reference to the accompanying drawings.

The reinforcing structure according to the present invention includes a reinforcing section shown in FIGS. 1 to 3, which is constituted by elements 1 to 4 of four crossed element juxtaposed layers (hereinafter simply referred to as "juxtaposed layers"). It has been done.

These elements are made of carbon, for example,
They are arranged as juxtaposed layers 5 to 8 (FIG. 1). juxtaposition layer 5
is, for example, located in the horizontal plane, while the juxtaposed layer 6 adjacent thereto is also located in the horizontal plane, but the juxtaposed layer 5
It is placed at a corner. That is, the elements 1, 2 of the two horizontally juxtaposed layers 5, 6 each form a given angle Q, which angle can be varied depending on the application of the composite material in which the reinforcement is fitted. . The remaining two layers, formed by juxtaposing layers 7, 8, are woven through the mesh formed by elements 1, 2.

These remaining layers each constitute a plane that is inclined with respect to the horizontal plane of the juxtaposed layers 1 and 2 and whose limit is the vertical plane.

It can be seen that the juxtaposed layers 7, 8 are at an angle to each other and have the same oblique angle with respect to the first two layers. In the embodiment shown in FIG. 1, if the elements of one of the four juxtaposed layers are arranged perpendicular to one side of an arbitrary regular tetrahedron, the elements of the other three juxtaposed layers are becomes perpendicular to the other three faces of the tetrahedron, which means that the juxtaposition layer 5
, 6 form an angle Q of cos Q=1/3, that is, 70030'.

Similarly, the elements of the juxtaposed layers 7, 8 also form an angle Q of cos Q=1/3. By this, and by the choice of tetrahedrons, each juxtaposed layer 5-8 has a line of symmetry XX'
It forms an angle 8 of 54o45. Each juxtaposition layer 5-8 is
Consisting of identical rigid elements of polygonal or circular cross section,
The axes of these elements are aligned in a single apposition layer (e.g. apposition layer 5
) If you think about it...Satoshishi and the remote residence are small.

Here, d'' is the diameter of the inscribed circle in the cross section of the element. This spacing is, of course, constant, where d is the diameter of the circumscribed circle in the cross section of each element. For elements with hexagonal cross section, d=--≧toxic. In the embodiment shown in FIGS. 1 to 3, and in particular as can be seen in the one in FIG. belongs to
Further, they are separated from each other by a distance equal to the diameter d of the inscribed circle of the element cross section.

Furthermore, elements 1, la of two adjacent juxtaposed layers 5, 5a
are arranged in a quincunx shape on a die as shown. Please pay attention to the following points.

That is, FIG. 2 shows the positions of the elements of the other three juxtaposed layers of the reinforcement. This is because in the direction D6 between the juxtaposition layers 5, 5a, 5b there is a parallel juxtaposition layer 6 containing the rigid element 2, while in the direction D7 and D8 there is a juxtaposition layer 7 and a juxtaposition layer 8. This is because there is an east composed of each. 3a and 3b show two successive sections along a plane perpendicular to the axis of symmetry XX' of the reinforcement according to the invention, the shaded areas indicating the small holes 9 between the elements. .

As can be seen in FIG. 3a, elements 3, 4 of juxtaposed layers 7, 8
are located on both sides of elements 1 and 2 of juxtaposed layers 5 and 6,
Meanwhile, below that, elements 3 and 4 are between elements 1 and 2, and at the next level immediately below, elements 1 and 2 are again between elements 3 and 4.
It is located in between. In FIG. 3b, the cross section shown here shows a position slightly shifted in the direction of the axis of symmetry XX' with respect to the cross section shown in FIG. You can see the layout.

The method for obtaining the above-mentioned reinforced composite material is to first form elements 1, 2 of a given corner, for example, such that any co-oriented juxtaposed layers give elements arranged in a quincunx of a dice. It is the stacking of juxtaposed layers that are alternately placed next to each other.

The elements forming the juxtaposed layers 7 and 8 are inserted into the mesh-like gap formed by stacking the juxtaposed layers 5 and 6, and the first to
The reinforcement section described in connection with Figure 3 is completed.

According to another method (FIG. 4), first two lattice frames 10,
11, each frame of which is composed of two planar meshworks superimposed to form an angle of 70 o 30'.

These silk-like structures may be composed of elements 1, 2 of FIG. 1, for example. The grid frames 10, 11 are arranged perpendicularly to the horizontal plane 12 and are separated by a distance Z which is a multiple of the diameter of the circle inscribed in the cross section of the element. A third silk of elements is provided across the two grid frames in a plane perpendicular to the grid frames, element 3 of this third network forming a 70o30 corner with elements 1, 2 of said grid frames. None, the distance between the rays of elements belonging to the same network is rock. Here, d' is the diameter of the circle inscribed in the cross section of the element. A fourth network of elements 4 is finally introduced across the hang grid frame in the same manner as described above.
Furthermore, this fourth network may be provided adjacent to the third silk, in which case its elements make 70o30' angles with the elements of the third network. When all the meshes similar to the third and fourth meshes are in place,
That is, when the lattice frame becomes saturated, more elements 1 and 2 parallel to the elements constituting the lattice frame may be inserted into the remaining gaps. When all gaps are filled, the reinforcement is complete and a coating is applied using one of the methods described below.

The elements constituting the east may be rigid bodies with polygonal or circular cross sections, but they may also be flexible bodies.

Equivalent rigid elements may be used in combination with flexible elements, the selection of element material and number depending on the application of the composite structure. Before coating the reinforcement, each element is
It may be coated with a suitable resin or carbon deposit compatible with the final coating that will complete the composite and provide it with functional properties.

The final coating may be carried out in any other suitable manner, so as to fill the spaces 9 in the reinforcement. This coating can be done by liquid flow, i.e., liquid impregnation, which removes the gases occupying the space and then injects under pressure the resin, which is first a polymerized phase and then a pyrolyzed phase. consists of things.

If the volume of the resin decreases by about 50% due to thermal decomposition, the impregnation process is repeated until all the spaces are filled. Other known coating methods may be used on the same machine.

This method consists of gradual infiltration by deposition of pyrolytic carbon obtained, for example, by decomposition of hydrocarbon gases, in order to rapidly obtain a high density of carbon when the coating is carbon-based, resulting in , resulting in a continuous and uniform coverage of all surfaces accessible to the carbon deposits. In a further coating step, the spaces in the reinforcement are progressively filled by successive deposits of thin coke layers, preferably obtained in three successive operations. Three successive operations involve impregnating the reinforcement with a low-velocity resin, such as phenolic or furan resin, and then evaporating it, leaving only a thin film of resin on the walls of the space. Premature filling is avoided and drying, polymerization and pyrolysis are the final step; the thin layer deposition cycle is started after pyrolysis until the space is saturated. Heat treatment can be very rapid if only a small thickness of resin is deposited with each cycle. The manufacturing process of the composite material having a reinforcing structure according to the present invention is not limited to the above-mentioned process, and various modifications can be made within the scope of the claims. Obviously, the reinforcement can be precoated according to one of the three methods mentioned above.

For example, if the coating of the reinforcement is obtained by a thermoset resin that is deliberately kept in a prepolymerized state, the elements can be glued at all their contact points by heating the resin to its softening point. , which strengthens the bonding of the composite structure. This softening can be used advantageously, for example, for plate positioning or for compacting reinforcements to increase their density and at the same time improve the looseness of the elements. Because the elements are wavy in their initial linear form, they are held more firmly in place.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing one embodiment of the reinforcing portion according to the present invention, FIG. 2 is an east cross-sectional view of the reinforcing portion in FIG. 1, and FIG.
Figures a and 3b are cross-sectional views of the reinforcing portions in Figures 1 and 2, and Figure 4 is a diagram showing a form of the process of making the reinforcing portions. 1-4... Elements, 5-8... Juxtaposed layers, 9.
...Small hole, 10,11... Lattice frame. Gengo/Koshisen 2 Hango 3 Hakusen 3b Hansen 4

Claims (1)

[Scope of Claims] A composite material having a reinforcing structure embedded in one row, the reinforcing structure having a polygonal or circular cross section and linear elements arranged in parallel. 4 reinforced surfaces, the first and second reinforced surfaces are alternately arranged parallel to each other,
and the elements of the first reinforcing surface are non-parallel to the elements of the second reinforcing surface, the third and fourth reinforcing surfaces are similarly arranged alternately and parallel to each other, and the elements of the third reinforcing surface are non-parallel to the elements of the second reinforcing surface. the first and second reinforcing surfaces and the third and fourth reinforcing surfaces intersect, and are impregnated or coated with a densification material. composite material. 2. A composite material according to claim 1, wherein the elements are all inclined at the same angle to the axis of symmetry of the reinforcing structure. 3. The composite material according to claim 1, wherein the elements of the first to fourth reinforcing surfaces are perpendicular to each surface of the regular tetrahedron. 4. The composite material according to claim 1, wherein the elements of the first to fourth reinforcing surfaces are separated by a distance equal to twice the diameter of the circumscribed circle of the cross section of each element. 5. The composite material according to claim 1, wherein the elements of the first to fourth reinforcing surfaces are spaced apart by a distance equal to twice the inscribed circle of the cross section of each element. 6. A method for manufacturing a composite material having a reinforcing structure, which comprises arranging linear elements having polygonal or circular cross sections in parallel so that first and second reinforcing surfaces are arranged alternately and parallel to each other, In this case, the elements of the first reinforcing surface and the elements of the second reinforcing surface are non-parallel, and by arranging elements similar to the elements of the first and second reinforcing surfaces in parallel to each other, the elements of the third and second reinforcing surfaces are arranged parallel to each other. The elements of the third reinforcement surface are non-parallel to the elements of the fourth reinforcement surface, and the first and fourth reinforcement surfaces are arranged so that the third reinforcement surface and the fourth reinforcement surface are parallel and alternate. A method characterized by inserting elements of the third and fourth reinforcing surfaces between elements of the second reinforcing surface, and impregnating or coating the reinforcing structure consisting of the first to fourth reinforcing surfaces with a densification material. .