# US 4,400,421 A · Four-directional structure for reinforcement

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- Number: US 4,400,421 A
- Document ID: US4400421A
- Status: Granted
- Kind: A
- Application number: 06/448,161
- Filed: 1982-12-09
- Granted: 1983-08-23
- Earliest claimed: 1982-12-09
- Assignees: The United States of America as represented by the Secretary of the Air Force
- Inventors: Edward R. Stover
- Web page: https://patentgrep.com/patent/US4400421A

## CPC

- C04B 35/80: Fibres, filaments, whiskers, platelets, or the like
- B29C 70/24: oriented in at least three directions forming a three-dimensional [3D] structure
- C04B 35/14: based on silica
- C04B 35/522: {Graphite (C04B35/536 takes precedence)}
- C04B 35/5607: {based on refractory metal carbides}
- C04B 35/5611: {based on titanium carbides}
- C04B 35/565: based on silicon carbide
- C04B 35/584: based on silicon nitride
- C04B 35/83: Carbon fibres in a carbon matrix
- C04B 2235/3251: Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof
- C04B 2235/425: Graphite
- C04B 2235/449: Organic acids, e.g. EDTA, citrate, acetate, oxalate
- C04B 2235/48: Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
- C04B 2235/5248: Carbon, e.g. graphite
- C04B 2235/5252: having a specific pre-form
- C04B 2235/616: Liquid infiltration of green bodies or pre-forms
- C04B 2235/6562: Heating rate
- C04B 2235/661: Multi-step sintering
- C04B 2235/94: Products characterised by their shape
- Y10S 428/902: High modulus filament or fiber
- Y10T 428/24058: including grain, strips, or filamentary elements in respective layers or components in angular relation
- Y10T 428/24124: Fibers
- Y10T 428/24132: including grain, strips, or filamentary elements in different layers or components parallel
- Y10T 428/249921: Web or sheet containing structurally defined element or component
- Y10T 428/29: Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
- Y10T 428/2913: Rod, strand, filament or fiber
- Y10T 428/2918: including free carbon or carbide or therewith [not as steel]
- Y10T 428/2973: Particular cross section
- Y10T 428/30: Self-sustaining carbon mass or layer with impregnant or other layer
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The structure comprises four groups of elongated rectilinear elements, with the elements of each group parallel to one another. The elements of three of the groups are mutually orthogonal and the elements of the other group are disposed diagonally to the elements of two of the three mutually orthogonal groups. The structure is useful for fabricating nosetips for maneuvering re-entry vehicles.

## Claims

### Claim 1

A 4-directional reinforcement structure for a composite material which comprises a plurality of repeating units, each unit consisting of a first, a second, a third and a fourth group, each group consisting of a plurality of elongated rectilinear elements in parallel relation and extending parallel to a respective direction and arranged in a plurality of rows; wherein a first portion of said first group of elements is disposed in a first plane and extends parallel to a first direction; wherein said second group of elements is disposed in a second plane parallel to said first plane, said second group extending parallel to a second direction which is approximately diagonal to said first direction; wherein a second portion of said first group is disposed in a third plane parallel to said first plane and extend parallel to said first direction; wherein said third group of elements is disposed in a fourth plane parallel to said first plane and extend parallel to a third direction which is approximately diagonal to said first direction and opposite the orientation of said second direction; and wherein said fourth group of elements is disposed in a plurality of spaced parallel planes, each plane being substantially perpendicular to said first direction, said fourth group extending parallel to a fourth direction which is substantially perpendicular to said first plane.

### Claim 2 (depends on 1)

The structure of claim 1 wherein the elements of said first group have a substantially square cross section, the elements of said second and said third groups have rectangular cross sections and the elements of said fourth group have an elongated hexagonal cross section.

### Claim 3 (depends on 2)

The structure of claim 2 wherein the interelement spacings of the elements of said first group is approximately 0.50 to 0.75 times the face dimension of said first group elements; wherein the width of the elements of said second group, said third group and said fourth group is approximately the same as the interelement spacing of said elements of said first group; wherein the depth of the elements of said second and said third groups is approximately 1.4 to 2.8 times the width of said elements; and wherein the height of the elements of said fourth group is approximately 1.50 to 3.25 times the width of said elements.

### Claim 4 (depends on 3)

The structure of claim 3 wherein the interelement spacing of the elements of said first group in said first and said third planes is approximately equal to the spacing between said first and said third planes.

### Claim 5 (depends on 3)

The structure of claim 3 wherein the interelement spacing of the elements of said first group in said first plane is equal to the interelement spacing of the elements of said first group in said third plane, and wherein the interelement spacing of said elements in said first and said third planes is different from the spacing between said first and said third planes.

### Claim 6 (depends on 4)

The structure of claim 4 wherein the interelement spacing of the elements of said first group is about 0.70 times the face dimension of said first group elements and wherein the depth of the elements of said second and third groups is about 2.00 to 2.20 times the width of said elements.

### Claim 7 (depends on 6)

The structure of claim 6 wherein the depth of the elements of said second and third groups is about 2.10 times the width of said elements.

### Claim 8 (depends on 1)

The structure of claim 1 wherein each of said elements consists essentially of a plurality of carbon fibers.

### Claim 9 (depends on 8)

The structure of claim 8 wherein the end count ratio of said elements in said first, second, third and fourth groups is about 3:3:3:2.

### Claim 10 (depends on 1)

The structure of claim 1 further comprising a 3-directional reinforcing structure adjacent to said 4-directional structure, wherein said 3-directional structure consists of an alpha group, a beta group and a gamma group, each group consisting of a plurality of elongated rectilinear elements in spaced parallel relation extending parallel to a respective direction and arranged in a plurality of rows; wherein said alpha group is a continuous extension of said first group of said 4-directional structure; wherein said beta group of elements is disposed in a plurality of spaced parallel planes substantially perpendicular to said first direction and extend parallel to said fourth direction in said 4-directional structure; wherein said gamma group of elements is disposed in a plurality of spaced parallel planes substantially perpendicular to said first direction and extend in a fifth direction which is perpendicular to said first direction and to said fourth direction; wherein said planes in which said beta group elements and said gamma group elements are disposed alternate, one with the other.

### Claim 11 (depends on 10)

The structure of claim 10 wherein the elements of said first group have a substantially square cross section, the elements of said second and said third groups have rectangular cross sections, the elements of said fourth group have an elongated hexagonal cross section, the elements of said alpha group are the elements of said first group, and the elements of said beta and said gamma groups have a substantially square cross section.

### Claim 12 (depends on 11)

The structure of claim 11 wherein the interelement spacings of the elements of said first group is approximately 0.50 to 0.75 times the face dimension of said first group elements; wherein the width of the elements of said second group, said third group, said fourth group, said beta group and said gamma group is approximately the same as the interelement spacing of said elements of said first group; wherein the depth of said elements of said second and said third groups is approximately 1.4 to 2.8 times the width of said elements; and wherein the height of the elements of said fourth group is approximately 1.50 to 3.25 times the width of said elements.

### Claim 13 (depends on 12)

The structure of claim 12 wherein the interelement spacing of the elements in said first group in said first and said third planes is approximately equal to the spacing between said first and said third planes.

### Claim 14 (depends on 12)

The structure of claim 12 wherein the interelement spacing of the elements of said first group in said first plane is equal to the interelement spacing of the elements of said first group in said third plane, and wherein the interelement spacing of said elements in said first and said third planes is different from the spacing between said first and said third planes.

### Claim 15 (depends on 13)

The structure of claim 13 wherein the interelement spacing of the elements of said first group is about 0.70 times the face dimension of said first group elements and wherein the depth of the elements of said second and third groups is about 2.00 to 2.20 times the width of said elements.

### Claim 16 (depends on 15)

The structure of claim 15 wherein the depth of the elements of said second and third groups is about 2.10 times the width of said elements.

### Claim 17 (depends on 10)

The structure of claim 10 wherein each of said elements consists essentially of a plurality of fibers.

### Claim 18 (depends on 1)

A maneuvering re-entry vehicle nosetip fabricated from a carbon-carbon composite material having the 4-directional reinforcement structure of claim 1 wherein said elements of said first group are oriented parallel to the axial direction of said nosetip.

### Claim 19 (depends on 10)

A maneuvering re-entry vehicle nosetip fabricated from a carbon-carbon composite material having the 4D+3D reinforcement structure of claim 10 wherein the tip portion of said nosetip comprises the 3D portion of said structure and the plug portion of said nosetip comprises the 4D portion of said structure, and wherein the elements of said first group are oriented parallel to the axial direction of said nosecone.

### Claim 20 (depends on 1)

A nosecone for a maneuvering re-entry vehicle, said nosecone having an associated nosetip, wherein said nosetip is fabricated from a carbon-carbon composite material having the 4D reinforcement structure of claim 1 wherein said elements of said first group are oriented parallel to the axial direction of said nosetip and wherein the elements of said first, second and third groups lie in planes parallel to the plane of bending of the nosetip and nosecone assembly.

### Claim 21 (depends on 10)

A nosecone for a maneuvering re-entry vehicle, said nosecone having an associated nosetip, wherein said nosetip is fabricated from a carbon-carbon composite material having the 4D+3D structure of claim 10 wherein the tip portion of said nosetip comprises the 3D portion of said structure and the plug portion of said nosetip comprises the 4D portion of said structure, wherein the elements of said first group are oriented parallel to the axial direction of said nosetip and wherein the elements of said first, second and third groups of said 4D portion lie in planes parallel to the plane of bending of the nosetip and nosecone assembly.