Large area pressurized meteoroid penetration detector panels with maximum inherent structural rigidity are provided. The panels measure directly the penetration rate in materials to be used in spacecraft. Panel structure include an interconnected cellular configuration in which the cells have spaced periphery welds and tufts in their centers. A spot weld is made at the center point joining the panels

White, E. C.

English

NASA Technical Reports Server

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
WASHINGTON. D.C. 20546
'"^7t^f(NSSa~Case~XLA~08916~2) PHESSUBIZED PANEL
^ -^Patent (NASA) 4 p CSCL 14B N73-28487
Dnclas
00/14 09876
KSI/Scientific & Technical Information Division
Attention: Miss Winnie M. Morgan
FROM: GP/Office of Assistant General Counsel for
Patent Matters
SUBJECT: Announcement of NASA-Owned U.S. patents in STAR
In accordance with the procedures agreed upon by Code GP
and Code KSI, the attached NASA-owned U.S. Patent is being
forwarded for abstracting and announcement in NASA STAR.
The following information is provided:
U.S. patent No. :_
Government or
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NASA patent Case No.
NOTE - If this patent covers an invention made by a corporate
employee of a NASA Contractor, the following is applicable:
Yes / / No / X/
Pursuant to Section 305(a) of the National Aeronautics and
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the first page of the patent; however, the name of the actual
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the Specification, following the words "... with respect to
an invention of ..."
£C'&tLff y* ux& #&
Elisabeth A. Carter
Enclosure
Copy of patent cited above
https://ntrs.nasa.gov/search.jsp?R=19730019755 2020-03-17T09:18:01+00:00Z
3,'744,3 °^
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United States Patent
White
[in 3,744,320
[45] July 10, 1973
[54] PRESSURIZED PANEL
[75] Inventor: Erskine C. White, Newport News,
[56] References Cited
UNITED STATES PATENTS
Va.
[73] Assignee: The United States of America as
represented by the Administrator of
the National Aeronautics and Space
Administration, Washington, D.C.
[22] Filed: Nov. 6, 1970
[21] Appl. No.: 97,472
Related U.S. Application Data
[62] Division of Ser. No. 777,765, Nov. 21, 1968.
[52] U.S. Cl 73/432 R, 73/170 R
[51] Int. Cl.. GOlw 1/00
[58] Field of Search. 73/432 R, 170 R
3,526,139 9/1970
3,238,774 3/1966
3,446,068 5/1969
Mayo et al 73/432 R
Gurtler 73/170 R
Slattery et al 73/170 R
Primary Examiner—Charles A. Ruehl
Assistant Examiner—Joseph W. Roskos
Attorney—Howard J. Osborn
[57] ABSTRACT
Large area pressurized meteoroid penetration detector
panels. The structure of the panels includes an inter-
connected cellular configuration in which the cells
have spaced periphery welds and tufts in their centers
at which point a spot-weld is made joining the panels.
5 Claims, 2 Drawing Figures
3,744,320
1 2
PRESSURIZED PANEL configuration has been found to greatly increase the
This application is a division of application Ser. No. overall structural rigidity of the panel. The detector
777,765 filed Nov. 21, 1968. panel 10 can be made to have cells conforming to any
The invention herein described was made to easily geometric shape. .However, it has been found that the
provide relatively flat, large area pressurized meteoroid 5 hexagonal configuration provides the greatest panel ri-
penetration detectors having maximum inherent struc- gidity because there are no straight line elements to
tural rigidity. These panels measure directly the pene- permit bending.
tration rate in materials to be used in spacecraft. Previ- FIG. 2 shows an explided isometric view of the appa-
ous detectors were semicylindrica! pressurized cell de- ratus for pressure forming the detector panels 10. A
lectors with small penetration areas which measured 10 prewelded panel, i.e., is formed by placing two cleaned
penetration rates in very thin materials. These were rel- sheets 12 and 13 of the metal desired to be tested to-
atively heavy configurations, often weighing 1.6 gether and welding the panel perimeter seams 14, the
pounds per foot of penetration area. Furthermore, the cell center spot wels 15, and the space cell perimeter
design and small size of each sensor permitted the pre- seams 16, the panel is then placed between two plates
sentation of only one penetration area (0.1 sq. ft. per IS of pressure forming apparatus. These consist of metal
sensor), while the method of fabrication, hand solder- bases 24 and 25 upon which steel perimeter clamping
ing, proved to be extremely tedious, time-consuming, plates 20 and 21 are screw mounted. The inner borders
and costly. In addition, the soldering method is not of these plates conform to the shape and size of the
compatible with the high temperature environments of panel perimeter seam 14. Located beneath these are
many planned missions. The present invention over- 20 surface restricting shims 22 and 23. These shims have
comes these shortcomings by providing unique metal linear surface protrusions 27 which regulate the expan-
forming fabrication techniques to readily produce a sion of the sheets at the vent spaces, and circular pro-
new type of pressure panel that has a maximum pene- trusions 26 which regulate expansion at the center spot
tration sensitive area-to-weight ratio, i.e., of at least welds. The shims serve a purpose more fully explained
0.787 Ibs. per foot of penetration area, as well as low 25 hereinafter.
volume. Other advantages are minimum area lost due The prewelded panel has a compressed air hose fit-
to fabrication, the ability to obtain various sizes and ting 18 attached by means of copper tubing to one
shapes, and simplicity of forming and fabricating panels sheet in one corner of the panel. There is an aperture
having inherent structural rigidity without preforming 32 in the upper half of the pressure forming apparatus
the material. 30 through which this fitting 18 protrudes so that once the
It is therefore an object of this invention to provide panel sheets are properly clamped in the pressure form-
a pressure panel that has a maximum penetration area- ing apparatus, the compressed air hose may be at-
to-weight ratio, low volume, and inherent structural ri- tached and the proper pressure of compressed air ap-
gidity. plied to the panel.
Yet another object of the invention is to provide a 35 Two positioning pins 27 and 29 which are attached
micrometeoroid detection panel which has both sides to the steel perimeter clamping plate 20, fit into two ap-
exposed to meteoroid penetration. ertures 30 and 31 located in the steel perimeter clamp-
Still another object of the invention is to provide a ing plate 21. These pins serve to properly aline the ap-
micrometeoroid detection panel capable of being used paratus parts.
in the temperature environments of various planets. 40 The prewelded panel plate is placed in position on
An additional object of the invention is to provide a top of the perimeter clamping plate 20 and overlapping
micrometeoroid detector panel which can be con- edges are crimped down along the sides of the metal
strucied of various thicknesses enabling penetration base 24. Holes 35 are bored in the sheets so that steel
testing of a variety of sizes and velocities of meteoroids. clamping bands 34 may be tightly bolted to the sides of
Another object of the invention is to provide an ap- 45 the metal base 24 by bolts 33 screwed into threaded
paratus and a method for the easy production of detec- bores 36 located in the sides of the metal base 20. In
tor panels having the hereinbefore mentioned advan- this way the crimped-over panel sheets are securely fas-
tages. , tened between the bands 34 and the sides of the base
These and other advantages of the present invention 24. This is done to prevent the panel sheet from pulling
will become more readily apparent from the following in in response to stresses exerted upon it during the
description. pressure forming process, for it has been found that the
In the drawings: panel has a tendency to pull in after a certain amount
FIG. 1 is an isometric view of a finished meteoroid of deformation has taken place when air pressure is in-
detector panel having centrally tufted cells in a hexago- troduced between the sheets 12 and 13. This is espe-
nal configuration. cially true depending on the thickness of the panels.
FIG. 2 is an exploded isometric view of the apparatus Once the panel has been adequately secured so as to
for the pressure forming fabrication of the detector prevent pull-in, pressure-forming is begun. This in-
panels of the present invention including an unfinished eludes a three-stop, sequential pressurization of the
panel. ,„ panel, employing various levels of air pressure within
Referring to the drawing in detail, FIG. 1 shows a certain physical constraints. For the fabrication of a de-
completed pressure formed pressurized detector panel lector panel out of two sheets of 0.017-inch thick 321
designated generally by the numeral 10. The detector stainless steel, the following steps are involved. The
panel 10 has hexagonally shaped cells 11, a welded pe- prewelded panel is securely clamped between the two
rimeter seam 14 and spaced cell perimeter welds 16
 65 surface restricting shims 22 and 23 which restrict panel
which create vent spaces 19 between the cells 11. The thickness to 0.125-inch. Air pressure at 200 pounds per
cells 11 have tufted centers 17 at which point a spot square inch is then introduced into the panel through
weld 15 has been made. The tufted center-spot weld the previously installed fitting 18. This causes the cell
3,744,320
corners to be expanded to the desired shape. After this
initial pressure forming procedure is completed, the air
pressure is released and the restrictions removed.
The how partially formed panel is then clamped be-
tween/a second set of shims to limit the panel cell thick- 5
ness/o 0.250 inch. The panel is then pressurized to 100
pounds per square inch to expand the cells about their
peripheries to the 0.250 inch thickness. Air pressure is
then released and all surface restricting shims removed.
While still in the perimeter clamping device, the 10
panel is then pressurized to 65 pounds per square inch,
completing the cell formation. After depressurization,
the formed panel is removed from the clamping device.
A pressure sensor of the type disclosed in U.S. Pat. No..
3,238,774 is attached to one of the cells. For purposes 15
of illustration, such a pressure sensor is shown diagram-
matically in FIG. 1 and is designated by the reference
numeral 40. Lines 41 connect the sensor with one of
the cells. Final pressurization to 45 pounds per square
inch is accomplished at table top at which time the cop- 20
per tube of the fitting 18 is crimped together, the fitting
removed, and the remaining length of tubing coiled up.
The panel is now ready to be incorporated into its satel-
lite configuration.
Because the cells are interconnected, the penetration 25
of any one of them by a meteoroid results in a pressure
.drop in the entire panel. The pressure sensor detects
and relays this to the satellite's data system for recorda-
tion.
These panels may be made in any shape or size and 30
with any cell configuration. A plurality of such panels
can be utilized so as to form a configuration which is
representative of any planned spacecraft.
While a preferred embodiment of this invention has
35
been described, it will be understood that modifications
and improvements may be made thereto. Such of these
modifications and improvements as incorporate the
principles of this invention may be considered as in-
cluded in the hereafter appended claims unless these
claims by their language expressly state otherwise.
What is claimed as new and desired to be secured by
Letters Patent is:
1. An apparatus for detecting meteoroid penetration
comprising:
a large area detector panel means having a plurality
of interconnected pressurized cells pressure
formed therein, said panel means including at least
a pair of opposed panels being sealed around their
periphery and said cells being tufted in their cen-
ters at which point a junction is made between said
opposed panels so as to give greater structural sta-
bility to the entire panel means while facilitating
reduced internal volume; and
means for detecting and permanently recording pres-
sure drop in said cells due to meteoroid penetration
of said panel.
2. The apparatus as in claim 1 in which the cells are
hexagonal in shape, said hexagonal configuration hav-
ing more inherent structural rigidity.
3. The apparatus as in claim 1 wherein the cell perim-
eters are welded; and spaces in said perimeter welds to
provide means for communication between the cells.
4. The apparatus as in claim 1 in which the cells can
be formed in any desired configuration.
5. The apparatus as in claim 1 wherein said tufted
junction is a spot-weld.
40
45
50
55
60
65


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