Static structures (e.g. – buildings) – Facer held by stiffener-type frame – Facer between exposed frame members having unitary flanges...
Reexamination Certificate
2000-08-25
2002-04-23
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Facer held by stiffener-type frame
Facer between exposed frame members having unitary flanges...
C052S428000, C052S156000, C052S189000
Reexamination Certificate
active
06374570
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The following U.S. Patent Applications by the same inventor, Elbert L. McKague, Jr. are being simultaneously filed and incorporated herein by reference: U.S. Patent Application entitled “Apparatus And Method For Controlled Damage Of Conformable Materials”; U.S. Patent Application entitled “Composite Structural Panel with Undulated Body”; and by the same inventor together with inventors Ronald P. Schmidt and David T. Uhl, U.S. Patent Application entitled “Composite Material Support Structures With Sinusoidal Webs And Method Of Fabricating Same”.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates in general to an improved structural member, and in particular to an improved structural beam, made by joining dissimilar materials. Still more particularly, the present invention relates to a structural composite preform for joining the web of a structure with flanges formed from dissimilar materials.
2. Description of the Prior Art
Structural support spars or I-beams typically have an “I” or “H” shaped cross-section, having a web with a crossbar or flange on each end of the web. The web and flanges extend integrally down the length of the beam, but may vary in shape, thickness, materials, etc. For example, one type of beam has a web formed from a first material (such as a metal) and flanges formed from a second, dissimilar material (such as a composite material). This type of beam has been pursued through a variety of design and manufacturing approaches since these structures offer the potential of providing excellent stiffness and strength-to-weight performance.
Prior approaches to joining dissimilar materials such as metals and composites have generally relied on mechanical fastening if the two elements are at an angle. As shown in
FIG. 1
, a spar
11
having an inverted T-shaped metal panel
13
with a flange
15
is joined to a flat composite plate
17
with mechanical fasteners
19
such that metal panel
13
and composite plate
17
are perpendicular to each other. In such an arrangement, metal panel
13
must have flange
15
to enable fastening to composite plate
17
. Moreover, the necessity of having flange
15
on metal panel
13
adds considerable cost to its fabrication since flange
15
significantly increases the volume of metal that must be purchased and then machined away. In addition, mechanical fastening involves drilling and countersinking holes, installing fasteners and, in some cases, treating the fastener heads to achieve a desired surface smoothness. These steps are expensive and can contribute an additional 25% to 60% to the overall cost of the spar assembly. Thus, an improved apparatus and method for forming a structural support member by joining dissimilar materials at an angle is needed.
SUMMARY OF THE INVENTION
A preformed component or “preform” for a structural support beam has a planar base with two longitudinal legs extending in parallel therefrom. A channel is defined between the legs of the preform, and a flat panel that forms the web of the structural support beam is inserted into the channel. The preform is a composite material having continuous filaments of woven or braided fiber. The preform is impregnated with a thermoset resin that joins and bonds the web to the flange of the structural support beam. The preform provides excellent structural support even if the web and the flange are formed from dissimilar materials such as metal and composite. The resin is structurally reinforced with oriented fibers in such a manner as to provide coupling strength between the joined members.
When a single filament is chosen for the preform, its properties are selected to minimize the difference in thermal expansion coefficients of the metal web and the composite flange. However, the preform may have two or more types of filaments with different properties. The filament in the base of the preform is chosen such that its axial thermal expansion coefficient matches that of the composite flange. The filament in the legs of the preform is chosen such that its axial thermal expansion coefficient matches that of the metal web. These filaments are used in combination to provide coupling strength between the joined metal web and composite flange by having the best structural fiber oriented parallel to the legs of the preform, and by its being interwoven into the base of the preform.
The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the preferred embodiment of the present invention, taken in conjunction with the appended claims and the accompanying drawings.
REFERENCES:
patent: RE21921 (1941-10-01), Greulich
patent: 4177306 (1979-12-01), Schulz et al.
patent: 4331495 (1982-05-01), Lackman et al.
patent: 5308675 (1994-05-01), Crane et al.
Bracewell & Patterson L.L.P.
Friedman Carl D.
Lockheed Martin Corporation
Varner Steve
LandOfFree
Apparatus and method for joining dissimilar materials to... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for joining dissimilar materials to..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for joining dissimilar materials to... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2904312