U.S. patent application number 09/860065 was filed with the patent office on 2002-03-14 for delamination prevention method and product.
Invention is credited to Carter, H. Landis, Malik, Frank Christopher.
Application Number | 20020031965 09/860065 |
Document ID | / |
Family ID | 26900181 |
Filed Date | 2002-03-14 |
United States Patent
Application |
20020031965 |
Kind Code |
A1 |
Carter, H. Landis ; et
al. |
March 14, 2002 |
Delamination prevention method and product
Abstract
A joint and method for forming a joint between two spaced apart
materials having dissimilar coefficients of thermal expansion
wherein the space is filled with a blended composite of twisted
fibrils of the two materials, preferably quartz and carbon, and an
adhesive, preferably an epoxy based adhesive.
Inventors: |
Carter, H. Landis; (Greer,
SC) ; Malik, Frank Christopher; (Simpsonville,
SC) |
Correspondence
Address: |
FLINT & KIM, P.A.
William D. Lee, Jr.
P.O. Box 10827
Greenville
SC
29603
US
|
Family ID: |
26900181 |
Appl. No.: |
09/860065 |
Filed: |
May 17, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60205170 |
May 17, 2000 |
|
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|
Current U.S.
Class: |
442/175 ;
442/179; 442/180 |
Current CPC
Class: |
Y10T 428/2936 20150115;
Y10T 428/251 20150115; Y10T 428/259 20150115; Y10T 156/1028
20150115; Y10T 428/2918 20150115; Y10T 442/2984 20150401; C09J 5/00
20130101; Y10T 442/2992 20150401; Y10T 156/1002 20150115; B32B 7/12
20130101; Y10T 442/2951 20150401 |
Class at
Publication: |
442/175 ;
442/179; 442/180 |
International
Class: |
B32B 005/02; B32B
027/38 |
Claims
What is claimed is:
1. A method of reinforcing an adhesively secured joint which joins
first and second materials have differing coefficients of thermal
expansion comprising the steps of: a) providing a first component
comprising a first material, and a second component comprising
second material, said components having respective surfaces which
are to be joined to each other; b) providing a composite which is a
blend of material of the first component with material of the
second component; c) providing an adhesive that will adhere to the
respective surfaces of the first and second components; and, d)
positioning the composite and adhesive between the surfaces to be
joined and joining said surfaces to form a joint with improved
resistance to thermal expansion and contraction.
2) The method of claim 1 wherein the composite comprises a twisted
yarn of carbon and quartz fiber.
3) As an article of manufacture, a twisted yarn comprising carbon
filaments and quartz filaments.
4) A reinforced joint securing spaced apart components of first and
second materials having differing coefficients of thermal expansion
comprising: a) a composite comprising yarns of twisted fibrils
which comprise said first and said second materials; b) an adhesive
that will adhere to the surfaces of first and second material, said
composite being positioned between said component, the space
between said components being filled with said adhesive and said
composite.
5. The joint of claim 4 wherein like first and second material are
carbon and quartz respectively and the adhesive is epoxy based.
Description
FIELD OF THE INVENTION
[0001] This invention relates to preventing delamination between
joined materials which have different thermal coefficients of
expansion. Specifically, the invention relates to providing a fiber
based interface reinforcement between two dissimilar materials that
are to be joined. Even more specifically, this invention relates to
unique fibers and their use in joining dissimilar materials.
BACKGROUND OF THE INVENTION
[0002] A long standing problem that is present in many fields where
a structure is constructed or components are assembled from
materials having different thermal coefficients of expansion is how
to compensate for the difference. Such a structure may be a roof, a
pipeline, concrete highway or bridge, nose cone for a rocket or an
assembly of parts for a space craft.
[0003] When materials having different thermal coefficients of
expansion are joined without provision for the expansion, the
result can be wrinkling, buckling, delamination, rupture and even
collapse. Typically, expansion joints are provided with cushioning
or stress and force absorbing elastomeric fillers. Joints have to
be especially designed to compensate for expansion and contraction
as ambient temperatures vary constantly. Accordingly, it is a
primary object of the present invention to provide a novel method
and product to deal with and compensate for the difference in
thermal coefficients of expansion between dissimilar materials that
are joined.
[0004] In space craft today, two differing materials which may be
joined are carbon panels or parts to quartz panels or parts. These
parts may be planar in configuration or they may have complex
curves and bends. The different coefficients of thermal expansion
make it difficult to achieve a secure joining of the materials.
Accordingly, it is another object of the present invention to
provide a satisfactory method and means for joining quartz
components with carbon components.
[0005] Applicant's unique and surprising solution to the foregoing
mentioned problems are described in the Summary of Invention and
Detailed Description which follow.
SUMMARY OF THE INVENTION
[0006] In one aspect the invention is a method of joining a first
and second dissimilar materials by blending the first and second
materials to form a composite which has a coefficients of expansion
intermediate of the two materials. The composite material can then
be adhesively joined to a respective surface of the first and
second dissimilar material at and in the interface to form a
sandwich construction:
First Material/Composite/Second Material
[0007] High strength adhesives such as those based on epoxy resins
are well known to those skilled in the art are used to adhere to
composite to the first and second interface surfaces.
[0008] The foregoing aspect of the invention is adaptable to
materials which blend compatibly such as polymeric and metallic
materials that are mutually soluble in each other and/or and can be
melt blended to form true mixtures or compounds and which include
blends, suspensions, and alloys. However, not all materials can be
readily blended by melt or solution blending. Accordingly, another
aspect of the invention is described below.
[0009] In a second aspect of our invention, fibrils or fibers of
the dissimilar materials are blended in strands or bundles which
can be twisted and spun into yarn and then woven or braided into a
fabric or composite yarn. This blended yarn may be the sandwiched
portion between joined interfaces and surrounded with an adhesive
which joins the material surfaces in the interface. The yarn or
fabric within the adhesive acts as a reinforcement much the same
way that concrete is reinforced by re-bars.
[0010] In still another aspect, carbon fibers may be twisted with
quartz fibers to form a strand wherein the amount of carbon and
quartz in the twisted yarn can be varied to provide a compatible
composite coefficient of thermal expansion depending on the size
and configuration of the quartz and carbon components being joined.
The composite yarn may be woven into a fabric to reinforce the
joint or braided into a mini-cable to fit within a joint. The
selection of the configuration of the composite structure depends
on the geometry of the joint being joined.
[0011] The invention will be better understood and appreciated by
the drawings and detailed description which follow.
DESCRIPTION OF THE DRAWINGS
[0012] The invention will be more readily understood from a reading
of the following description and by reference to the accompanying
drawings forming a part thereof, wherein an example of the
invention is shown and wherein:
[0013] FIG. 1 is a schematic representation of a twisted yarn which
blends fibers of two dissimilar materials, and,
[0014] FIG. 2 is a schematic representation of a joint which
employs the present invention wherein the joint is filled with a
composite fiber and adhesive.
DESCRIPTION OF A PREFERRED EMBODIMENT
[0015] Turning now to FIGS. 1 and 2, one preferred embodiment of
the invention will be described. FIG. 1 shows a yarn strand 3 which
comprises quartz fiber 1 twisted around carbon fibers 2. These
yarns have been twisted by an RTS Twister which is a twisting
apparatus that is well known to those skilled in the art. In the
general case, the weights of carbon and quartz per unit length will
be relatively equal. The quartz fiber preferably is direct sized
with a coupling agent which is preferably a saline coupling agent
that is well known in the art. The fiber linear density may range
from 100-5000 denier. The quartz fibers can be obtained from QPC,
Inc.
[0016] The carbon fibers are preferably those sold as Amoco T-300
and the fibers come in weights of 3,6, and 12 K meaning 3000, 6000,
and 12,000 filaments per strand.
[0017] The quartz and carbon filaments are wound or twisted by the
RTS Twister and the results have the appearance schematically as
shown in FIG. 1 where quartz fiber and carbon fiber 2 are mutually
twisted together.
[0018] Turning now to FIG. 2, a representative joint is shown
schematically. Component 10 comprises quartz and component 20
comprises carbon. Then components may be planar panels or other
components of more complex geometry. The blended yarn 3 is a
representation of a material woven from the yarn and the ends can
be seen in cross-section. In a small joint a single braided strand
might be sufficient. Filling the joint is epoxy based adhesive
which may be an epoxy cyanide or other organic adhesive which is
well known. The composite reinforced joint provides a secure
joining of the carbon and quartz materials which resist the stress
and forces of thermal expansion and provide security against joint
failure that cannot be achieved with an adhesive alone.
[0019] While we have shown and described particular embodiments of
our invention, modifications and variations thereof will occur to
those skilled in the art and who subsequently observe the invention
or read the specification. We wish it to be understood therefore
that the claims below are intended to cover such modifications and
variations which are in the scope and spirit of our invention.
[0020] What we claim is new and desire to secure by letters patent
of the United States is claimed below:
* * * * *