Column properties of corrugated aluminum alloy sheet (Airplane Branch report)

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File 629.13/Un3as/No. 699
INDUSTRY &. SCIENCE
AIR CORPS TECHNICAL REPORT No. 3227
AIR CORPS INFORMATION CIRCULAR
Vol. VII
PUBLISHED BY THE CHIEF OF THE AIR CORPS. WASHINGTON, D. C.
June 15, 1935
\7
(AIRPLANE BRANCH REPORT)
UNITED ST A TES
GOVERNMENT PRINTING OFFICE
WASHINGTON : 1935
Ralph Brown Draughon
LIBRARY
JUN 19 Z013
Non·Depoitorv
Auburn University
No. 699
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THE COLUMN PROPERTIES OF CORRUGATED ALUMINUM
ALLOY SHEET
(Prepared by Capt. C. F. Greene and C. G. Brown, Materiel Division, Air Corps, Wright Field, Dayton, Ohio,
March 5, 1930)
OBJECT
The purpose of this report is to present the properties
of c;orrugated aluminum alloy sheet in column action,
as determined by a series of tests on sheets of varying
lengths, thickness, depths of corrugations, and number
of corrugations.
SUMMARY OF RESULTS
The unit stress at which buckling occurs is a function
of the ratio of the radius of curvature to the thickness
of the corrugations ( ~) ·
F or a corrugat 1. 0n o f gi. ven TR, the re i.s a maxu. num um' t
stress which is not exceeded by decreasing the length
of the sheet.
In the bending range, the allowable stress may be
determined from the straight line-Euler equation for
aluminum alloy, using a proper coefficient of fixity.
The formulas a re:
Short columns,
Critical!:_
p Long columns, Eulers
straight line formula in column formula
action
C= I (pin ends) P /A=48,00Q--400 !:_ 80 P/A=l04,000/ ( ~)' p
C=2 ____ _______ P /A=48,000-280 !:__ 114 P/A =208,000/ ( ~) 2
p
C= 3 __ _________ P/A=48,000-230 !:__ 138 P /A=312,000/ ( ~) 2
p
The lightest column to carry a given load will be one
having such a ratio of~ that the~ of the column is at
the point of change from column failure to buckling.
For a narrow sheet having a low coefficient of fixity
t he effect of supporting the edges is considerable. ID
the case of a sheet of four corrugations tested on knife
edges, supporting the edges doubled the load that the
sheet couJd carry.
The radius of curvature used in determining the ratio
¥ should be obtained from the actual sheet where pos­sible,
particularly for thin material.
MATERIAL
The material used in these tests was furn ished by the
Aluminum Company of America, in a heat-treated con­dition,
with the following properties:
Spec. no.
248 ____ ___ ____ ___ __ ______ 0.0145
176 _ - --------· - - -- ---- - -- . 031
17!_ _ - -- - -- - - - -- --- - - - - -- . 081
L b./sq. in .
58, 600
61, 600
64, 450
Lb./sq. hi.
40, 000
41, 950
48, 350
Percent
· 11
21
16
The above properties were determined by test using
samples cut from specimens of 3%-inch pitch.
Three pitches of corrugation were used, l Y.-inch,
2Vi-inch, and 3Ys-inch, with the thickness of sheet vary­ing
from 0.012 to 0.080. The maximum thickness for
each pitch was 0.032, 0.050, and 0.080, respectively.
Specimens of 2, 4, and 6 corrugations were used in
the tests on the 27f-inch pitch. The corrugated sheet
varied somewhat from t he Army standards shown in
fignre 5. The variation was considerable in the t hin
sheets, as may be seen from the measured dimensions
of the specimens.
PREPARATION OF SPECIMENS
The specimens were first cut approximately to size,
using a metal cutting saw.
For the purpose of trimming the ends square and
parall el, wooden forms such as t hose shown in figure 2a
were prepared. These were in pairs about 2 feet long
and wide enough to take the widest specimens.
The longer block of the pair, which was the lower in
use, had inserted in one end a strip of maple extending
across its width. This strip was carefully finished
square to the bottom and to the axis of the corrugations
of its upper surface. The corrugations were fin ished
parallel to the bottom surface of the fo rm.
A woodworking shaper was used for trimming the
specimens. Plain straight-edged blades were set in the
shaper head so as to come just to its periphery. Blocks
of the same height were clamped to the shaper table as
shown in figure 2b. The shaper head \l'as then ad­justed
to a height such that when the forms were
placed in the blocks the smooth portion of the shaper
head was at t he height of the squared maple strip.
(1)
The specimen to be trimmed was placed between the
two halves of the corrugated forms, the edge protruding
slightly from the squared end to be trimmed. The
specimen was clamped t ightly in place by C-clamps at
each side of the wooden forms, and passed across the
moving shaper blades.
One or two cuts were usually sufficient to square the
ends. Considerable difficulty was experienced in fin­ishing
the thin stock when the specimens were of short
length or of extreme width. This was due to lack of
clamping action at the center of the wide forms. In
order to obtain parallel ends such specimens were
backed up against ·a longer specimen previously
trimmed.
2
The edge of the specim'ens were trimmed with a small
metal shear which gave satisfactory results. The
FH:URE 2a .
FIGURE 2b.
above method proved far more satisfactory and faster
than trying to mill the ends square, even with the
heaviest stock.
When the first results were computed and plotted,
several places appeared where more data were essen­tial.
Lack of additional stock made it necessary to
cut some of the longer specimens into shorter lengths.
The same reason was responsible for the use of the odd
size of 3)1:i-inch corrugations. Especial care was taken
to select only lengths of specimens that were straight
and free from defects or failures.
METHOD OF TEST
The majority of the specimens were tested on a
50,000-pound Olsen testing machine. For short spe­cimens
of 0.080-inch stock a 100,000-pound machfne
was used.
The test surfaces of the moving and fixed heads of
the testing machine were checked as parallel planes.
strips were used top and bottom, and were of sufficient
size to properly take the load on the columns tested.
A 1-inch by 4-inch pine bar, C, was secured to the
fixed table by means of C-clamps, in a position such
that when a 1-inch square oak bar, B, was placed
against it, a vertical face of B was parallel to and
directly under the face of bar A. This position was
determined by means of a steel square.
The test specimens were pressed securely against the
locating blocks, A and B, by means of a straight faced
block extending across the width of the specimen, so as
to obtain the same depth at each side and at each end.
Enough load was then applied to hold the specimen in
place while the locating bars were withdrawn. The
free edges of the sheet were then secured by means of
wooden edge clamps cut about Ys of an inch shorter
than the length of the specimen. Only about Ys-inch­%
6-inch of each edge was secured. These clamps may
be seen in figure 20. The column was then loaded to
failure.
Before the specimen was placed in the testing
machine its length, thickness, and number of corruga­tions
were determined. The width and depth were
determined just after the locating bars had been
withdrawn.
In order to verify the behavior of the columns under
pin ended conditions, a number of tests were run on
knife edges. The specimens tested were of lY,-inch
pitch, %-inch depth, 0.012-i.nch thickness, and four
corrugations. These tests were conducted on a 20,000-
pound Olsen testing machine.
The set-up is clearly shown in figure 20. This
photograph also shows the blocks used for centering
the specimens over the knife edges. These were
removed during the tests. The knife edges were
aligned by placing a straight round rod in the V of
the lower knife edge and then running the upper V
down until the rod was securely clamped between the
two. Once located they were retained in position by
notched wooden strips clamped to the lower table
of the testing machine.
SECTION PROPERTIES OF THE SPECIMEN
Early in the tests it became evident that to deter­mine
the areas of the specimens from their thickness,
width, and number of corrugations was not sufficiently
accurate. Accordingly, each specimen was carefully
weighed. Then, knowing the density of the material,
2.76 _grams per cubic centimeter by test, and the
length of the specimen, its weight could be determined
quite accurately.
A comparison of the areas determined by the two
methods showed variations of from 3 to 10 percent.
The expressions for the areas are­W
A = 0.0221y
where
A square bar of steel, D (fig. I), having smooth and
parallel faces, was bolted to the moving head. Attached or
to one side of D were L-shaped supports, the short leg
A= area in square inches
W = weight in grams
L=length in inches
w of the L projecting under D to provide support for a A = l0.02 L~
%-inch square steel bar, A, and a bearing strip of Ys­inch
aluminum alloy. These alluminum alloy bearing
where
W =weight in pounds
,,--
The radius of gyration, p, was obtained from the
actual pitch to depth ratio, using figure 3.
Figure 4 shows the radius of curvature in terms of
pitch and depth for pitch and depth ratios.
In figure 5 are shown, for purposes of comparison,
the properties of t he Air Corps standard corrugations.
The moment of inertia, I , of standard corrugated
sheet is given by the expression-
I = 0.155tD2
where
t= thickness of sheet in inches
D =over-all depth in inches
I = moment of inertia per inch width, in inches'
DISCUSSION
In order to clearly define the buckling point, ~ was
plotted against f for each pitch and thickness as in
p
figures 8 to 17, inclusive. These
clearly the behavior of the columns.
curves indicate
It is noted that
L
they behave according to some function of - up to a
p
certain ~ and t hen failure at this same~· even though
!::_ is decreased.
p
Referring for instance to figure 10, failures at an f p
of greater t han about 60 would be in column action.
Failures at an f of less t han about 60 would be in
p
buckling.
A specimen that has failed in bending, provided that
the failure has not been too far by excessive travel of
t he testing-machine head, will very nearly recover its
original straightness, and on a second test will carry a
high percentage of its original load.
A failure in buckling, however, is complete.
A failure in column action is characterized by a
lateral deflection of the center of the specimen. A
buckling failure differs in t hat t here is usually no bowing
of the specimen. It merely shortens. Figure 21 shows
the failures occurring in different sheets.
The individual column curves were superimposed as
shown on figure 18. Through these curves an average
column curve, figure 19, was drawn.
It is evident that the above curve does not suffice,
in that it does not clearly define the p oint at which
buckling occu rs.
The buckling ·~, as determined by lines of constant
~ of figure 18 or 19 were plotted against t he ratio ~·
where R is the radius of curvature of the corrugation
and t t he thickness. Figure 7 was the result.
On figure 6 were drawn the straight line-Euler
curves for dural for C=l, C=2, and C=3. F or con-venience
in use, the buckling ¥'s were also placed upon
t his sheet.
It is apparent that for C=3 the above formulas
would apply very well to the flat end conditions, giving
3
L .
slightly conservative values at low -'s a11c! a~ain at
p
high f 's.
p
In figure .9 are plotted the results of the knife-edge
tests, showing that the formulas again apply when C= 1.
Figure 7 indicates that the highest stresses can be
developed by using a small ratio of ¥· This is most
easily accomplished by a decrease of pitch with con­sequent
decrease in depth. But a decrease in depth
resul ts m. a d ecrease m. p an d an m· crease m. L- ·
p
If ~ is increased the allowable ~ in column action is
decreased, hence there is a possibility of decreasing the
R
allowable load on a column even though T was de-creased.
Apparently, there must be a compromise
between ~ and ~ for the lightest design (high est
allowable ~) ·
To illustrate this more clearly and at the same time
to show the use of the curves, an illustration will be
presented.
The conditions of the problem shall be:
L = length of unsupported sheet= 12 inches
W= width between edges of sheet = 12 inches
We= corrugated width= 1.2 W = 14.4 inches
p
n = 3~
P = pitch in inches
D = depth in inches
P =end load on corrugations= 7,500 lb.
Consider C= 2
The unknowns that the designer must face are t, D,
p
and "If
Three depths are commercially available, % inch, %
inch, and 1,Ys inches which will be considered for example
only as it was made up specially for these tests. Sheet
thickness available ranges from 0.012 inch upwards,
in steps of 0.004 inch.
The procedure is as follows:
Depth (inch)__ __________________ _______ ______ Vs l )i
-----
p=0.359 D ___________ ___ __________ ______ inch __ 0.139 0. 269 0.404
86 44 30
L
- - - - - - ----- - - - -- ---- - - -- ----- - - -- -- - -- -- ---- p
From fig. 6 C=2,--!:. incolumnaction _lb./sq. in __ 24, 000 36, 000 40, 000
0. 312 0. 208 0. 187
0.022 0. 014 0. 013
Area requ1. re d Pp/A _________ _____ squ are t. nch __
t= A / 14.4 __________ _______________ ___ ____ inch __
Nearest available sheet . ______ __________ do ___ 0. 024 0. 016 0. 016
1R =.94-t D- (fig. 4) _____________ ___ ___ __ _________ _ 15 45 67
38, 000 122, 000 16, 000
21, 700 32, 500 32, 500
Allowable buckling load (fig. 7) __ ___ lb./sq. in __
Actual :pA - ________ __________ __ ____ __ ____d o ___ _
In the above case it is seen that the only 1 of the 3
sizes considered that will carry the design load is a
%-inch depth, 1 ~-inch pitch, 0.024-inch sheet. The
other columns buckle before they approach the allow­able
column load.
Figure 6 can be used in place of figtire 7 by inter·
polating between T's,
The example will be carried one step further to show
the results of using a special corrugation. Two depths
between % inch and % inch will be considered.
Depth (inchl -------------·--------- - - %
--- ---- - - --
P- - - -- - - ---- -- --- -- --- ______ ____ inch ._ 0.139 0. 1795 0. 225 0. 269
L
----- ---------- -- ----- --------------- 86 67 53 44
p
Allowable AP .m co I umn act1. 0n
lb ./sq. in .. 24, 000 29, 000 33, 000 36, 000
A=area required ____ __ __ square i.nch __ 0. 312 0. 259 0. 227 0. 208
t required . __ ________ . __ __ _____ . inch .. 0. 022 0.018 0. 016 0. 014
Nearest available sheet_ ________ do .... 0. 024 0. 020 0. 016 0. 016
R
T·------ ----------------------------- 15 24 37 45
Allowable buckling Joad . . lb .fsq. in __ 38, 000 31. 000 25, 000 22, 000
p
Actual A: ---- - - _______ _________ do .... 21 , 700 26, 000 32, 500 32, 500
From the above table the maximum developed stress
that is below both the allowable buckling and column
action unit stresses is 26,000 pounds using a depth of
~ inch.
There would be, by using the }~ -inch depth, a saving
of 0.004 inch of metal, or 16.6 percent of the weight
of the heavier corrugated sheet.
SIDE AND END CONDITIONS
4
During the early part of the tests, specimens were
tested both with and without side clamps. Without
the side clamps similar specimens failed at from 65
percent to 85 percent of the load for those with clamps.
In each case the free edges buckled and resulted in the
reduction of the effective number of corrugations from
~~ to l}t The variation in the effective number of
corrugations caused the decision to conduct the re­maining
flat end tests using supporting clamps on the
e:iges.
In the knife-edge tests, a true pin ended condition
could not be obtained when using the edge clamps.
In this case, the edges had to be free to deflect with
the center of the column. The effect of supporting
the edges of a sheet of four corrugations can be seen
in figure 9. Supporting the edges causes them to effec­tively
support the center corrugations, partially pre­venting
them from deflecting laterally .
This effect, of course, decreases as the width of the
sheet increases. It is further dependent upon end
conditions, being greater for low values of the r estraint
coefficient C.
Side or end conditions had no appreciable effect on
the ultimate buckling load. The end conditions,
however, change the !::. at which buckling starts, as can
p
be seen from figure 9. The failures on this figure at
!::_,s of 38 and 51 were buckling failures.
p
The average of these points falls for all practical
purposes at 28,000 pounds per square inch, the buckling
load for the same sheet for flat ends. Since it may
be concluded from the flat end tests that the ultimate
buckling load would not change with a further decrease
of !::., no tests were made at lower values of !::.. The
p p
buckling failures even on knife edges were by a shorten­ing
of the column and not by bowing at the center.
No attempt will be made in this report to determine
a relation between end and side conditions because of
the lack of data and ·variance of test and design con­ditions.
·-.
Eccentricities in corrugated construction should not
be overlooked.
In the figure below, showing a splice between t\YO
sheets and a stiffening angle, the rivets have been
placed only in the bottoms of the corrugati9ns. This
results in an eccentric moment of value,
M = Pxe
where e is half the depth of the corru gations.
--J-1- ---P
The total stress on the column will be,
where
P = load on corrugated sheet
A=area of corrugated sheet
M = Pxe
Y = half the depth of the corrugation
I = moment of inertia of the corrugation
In this case, the allowable column must be deter­mined
by a formula suitable for combined bending and
compressive stresses in aluminum alloy columns (ref­ence
A. D. M. 968).
The eccentricity can be eliminated by placing the
rivets symmetrically about the center line of the sheet,
or by placing the rivets along this line.
The allowable fiber stress in combined bending and
compression should not exceed the allowable stress in
buckling.
Some interesting results are shown in table V.
Specimen 0 was chosen to determine the effect of
rivets in buckling. Accordingly, a row of Ys-inch rivets
was placed across the specimen, 1 inch from the end
with a rivet in each corrugation. Buckling occurred at
a higher load than in two similar specimens without
rivets, and occurred at the center, rather than at the
rivets where it was expected to appear.
Specimens 244 and 245 were chosen to determine the
effect of the rivets on a bending failure. In these cases,
2 rows of rivets were used, 1 row 1 inch from the end as
before, and another across the center of the specimen.
The results showed in each of the tests the rivets had
no effect worthy of consideration.
In the above cases the area removed by the rivet
holes was small in comparison to the total area of the
specimens, and was probably more than made up by
the grip of the metal heads. If the specimens had been
pierced by relatively large holes, a reduction of load
would probably have been noted.
. A few specimens were tested to determine the strength
that they would develop if straightened.
Specimens 86, 90, and 92 failed originally in buckling.
The failures were hammered out using a round rod of
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13
FIGURE 18.
- i £ ~=!_tJl 13:1} ~ - )1 ' D = '" ' •
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FIGURE 19.
't-- t-i
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nearly the same radius as that of the corrugations.
Strangely, upon being retested, the specimens buckled
at other points than the original failure. The strength
after straightening ranged from 67 percent to 90 per­cent
of the original strength.
Specimen 110 failed originally in bending. This
specimen was difficult to straighten and when retested
was slightly bowed. However, it developed 95 percent
of its original strength.
14
The above results should not be considered conclu­sive
for the number of tests is too few. They do indi­cate,
however, that the material is capable of taking
50 percent or better of its original load if straightened
after failure.
Metal that has been elongated greatly by the failure
should not be considered as capable of taking as high
a percentage as was taken by the test specimens which
were carried only to the point of failure.
TABLE !.- Corrugated dural sheet tested as fiat -ended col·umns
[% depth- 1!4 pitch- fixed edges]
Num-
I
p
ber Widtb Pitch Depth p Length L Area A Load -
T est no. corru- t w p D Weight p A
75 p L (in.) - ga tions (in .) (in .) (in.) p (sq. in.) (lb.) (lb./
n s q . in .)
- ----- - -- - - - - -- ---- --- - ----- - ------ - - --- 129 __ ___ _________________ _
130 ______________ _________ 4 0. 012 4. 80 1.20 0. 40 3. 00 0.143 3. 98 27. 8 13. 16 g 0. 0727 1, 820 25, 000
4 . 012 4. 85 l. 21 . 40 3. 03 . 143 3. 85 26. 9 12. 50 g . 0717 1, 870 26, 100
13L ____________ __________ 4 . 012 4. 90 1. 22 . 39 3. 14 . 140 3. 90 27. 3 12. 75 g . 0724 1, 750 24, 200
132 ___ ____ --- - ---------- -- 6 .012 7. 20 1. 20 . 41 2. 92 . 146 4. o:i 27. 6 20. 70 g . !138 2, 600 22, 850
133 __ ___________ --- ------- 6 . 012 7. 20 1. 20 . 41 2. 92 . 146 3. 88 26. 6 20. 10 g . 1148 2, 580 22, 450 134 _____ _____________ _____
6 . 012 7. 25 1. 21 . 40 3.02 . 143 3. 88 27. l 20. 30 g . 1158 2, 570 22, 200
13.5 . . ___ ____________ ------ 6 . 019 7. 23 1. 20 . 40 3.00 . 143 3. 87 27.0 29. 60 g .1690 5,880 34, 800
136 •. ____ _________ ___ _____ 1; . 019 7. 15 1. 19 . 40 2. 97 . 143 3. 85 26. 9 29. 60 g .1700 6,380 37, 500
138 __ ___ _________ ___ ___ ___
6 .033 6. 95 1. 16 . 43 2. 70 . 153 4. 00 26. l 50. 80 g . 2805 12, 450 44, 400
113490 __________ -__- -__-_- -_-_-__-_- -_-_-__-_-_- _-_- 6 . 0325 6. 95 1. 16 . 44 2. 64 .156 3. 98 25. 5 50. 80 g . 2820 12. 740 45, 200
9 _______ ___ __ _____ _____ ___ 6 . 0315 6. 90 l.15 . 43 2. 68 . 153 3. 92 25. 6 47. 50 g . 2680 12,000 44, 800
101.. __ ________ ____ ____ __ _ 6 .012 7. 15 1.19 . 40 2. 98 . 143 8. 01 56. 0 39. 20 g .1080 3,000 27, 800
102 ____ __ ___ ___ __ _____ ___ 6 . 012 7. 15 1.19 . 40 2. 98 . 143 7. 90 55. 2 40. 75 g .1140 3, 760 33, 000
6 . 012 7. 18 1.19 . 40 2. 98 . 143 7. 93 55. 5 39. 20 g .1092 3, 300 30, 200
"------------ ---- ----- ---- 6 . 019 7. 00 1. 16 . 40 2. 90 . 143 8. 00 56. 0 58. 0 g . 1600 5, 940 37, JOJ 7 __ ___ ______ ___ __________
o_ _________ ______ _________ 6 . 019 6. 98 1.16 . 40 2. 90 .Wl 8. 03 56. 0 58. lg . l600 5, 970 37, 250 3 ____ ____________ _____ ---- 6 . 019 7. 00 1.16 . 40 2. 90 . 143 7. 95 55. 6 ---- ---- -- . 1600 6, JOO 38.100
110 __ __ _______ ___ ______ ___ 6 . 032 6. 90 1.15 .40 2. 88 . 143 7. 97 53. 0 100. 4 g . 2785 9, 790 35, 100
6 . 031 6.89 1.15 .40 2. 88 . 143 5. 94 41. 5 71. 2 g . 2656 JO, 670 40, 100
109. ___ __________ __ ___ ____
6 . 031 6. 90 1. 15 . 40 2. 88 . 143 5. 92 41. 3 71. l g . 2660 10, 800 40,600
90 __ ____ ___ ____ __ __ __ _____
6 .012 7. 12 1. 18 . 39 3. 03 .140 9. 96 71. l 51. 2 g . JJ34 3, 500 30. 800
9L ____ ___ ______ ___ _____ __
92 __ ______ ___ ______ _______ 6 . 012 7. 15 l.19 . 40 2. 98 . 143 10.00 70. 0 51. 7 g . JJ42 3, 450 30, 200
6 . 012 7. 20 1. 20 .40 3. 00 . 143 10.00 70. 0 51. 5 g . 1138 3, 520 30, 900
87 __ ___ ________ ____ __ ___ __
6 . 012 7. 22 1. 20 .40 3. 00 . 143 11. 95 83. 5 59. 4 g . 1098 3,000 27, 300
88 __ __________ ____ ____ ____
6 . 012 7. 36 l. 23 . 39 3. 16 .140 11. 94 85. 4 60. 5 g . 1119 3, 020 27, 000
84 ___ ___ ___________ _____ __
85 ___ ___ __ _____ ____ ___ ____ 6 . 012 7. 15 1.19 . 38 3. 14 . 136 13. 85 102. 0 72.0 g .1150 3, 000 26, 100
86 _____ _______ ____ ______ __ 6 . 012 7.15 1.19 . 39 3. 06 . 141 13. 75 92. 5 71. 2g . 1143 3, 420 29, 900
17 _______ ____ __ ________ ___ 6 . 012 7. 23 1. 20 . 40 3. 00 .143 13. 84 97. 0 71.8 g . 1145 2,950 25, 800
6 . 012 7. 15 1.19 .38 3. 14 . 136 15.08 111. 0 ------- --- . 1143 2, 650 23, 150
18 ________ ________ ___ __ ___
13 ____ ____ __ ___ ___ _______ _ 6 . 012 7. 10 1. 18 . 38 ~.10 .136 15. 08 111. 0 - ----- --- · . 1137 2, 700 23, 800
lL. _______ ___________ ____ 6 . 019 7. 07 1.18 . 41 2. 88 .143 15. 01 105. 0 -------- -- . 1615 4, 360 27, 000
6 . 032 6. 91 1.15 . 40 2.88 .136 14. 97 110. 0 - -------- - . 2660 6, 710 25, 200
12 ___ __ ___ ______ ___ _______
6 . 032 6. 99 1. 17 . 38 3. 08 .136 15. 04 110. 5 - ----- ---- . 2695 6, 300 23, 400
23 __ ______ __ ____ __ __ ____ __
24 __ ____ _______ ___ ________ 6 .012 7. 25 1. 21 . 40 3. 03 .143 21.12 148. 0 - --- ------ . I 158 2, 025 17, 500
25 ____ _________ ___ ________ 6 . 012 7.17 1. 20 . 38 3. 16 . 136 21. 03 155. 0 --- - ----- - . 1145 1, 840 10.100
6 ,012 7.15 1.19 . 38 3. 14 . 136 21.11 155. 0 -- -- ------ . I 142 1. 890 16, 500
21_ _____ -- - --- - --- - -- - ---- 6 . 019 7.17 1.19 .38 3. 14 . 136 21. 02 154. 5 --- - -- -- -- . 1640 2, 560 15, 600
22 ___ _________ _____ _______
6 . 019 7.12 1.18 . 38 3. 10 . 136 21. 01 154. 5 -- ---- --- - .1628 2,800 17, 200
19 ____ __ ________ ___ ___ ____
6 . 032 6. 88 1.15 . 38 3. 03 . 136 20. 98 154. 0 ---- -- -- -- . 2780 5, 110 18, 400
20 _____ ______ ____ _______ --
6 . 032 6. 88 . 1.15 . 40 2.88 . 143 21.16 148. 0 ---- -- ---- . 2780 4, 610 16.600
225 ___ ___________ _____ ____
4 . 031 4. 63 1.16 . 42 2. 76 . 151 2. 75 18. 2 21. 5 g . 1730 7, 870 45, 500
226 ________ ____ ___ ______ __ 4 . 031 4. 65 1. 16 . 43 2. 70 . 155 3. 00 19. 3 24. 1 g .1775 7, 920 44, 550
227_ _____ __ -- -- - - - - -- -- - -- 4 . 030 4. 66 1.16 . 44 2. 64 . 158 3. 08 19. 5 24. 5 g . 1760 7,300 41, 500
222 _______________ __ - - - -
4 . 031 4. 57 l. 14 . 40 2. 85 . 144 3, 75 26. 0 29. 8 g .1755 7, 840 44, 550
2ZL ______ .... - -- - . . - __ - ~ 4 . 031 4. 50 1. 12 . 42 2. 70 . 151 3. 84 25. 4 30.0 g . 1727 7, 510 43, 500
224 _____ __________ -- -- --- - 4 . 031 4. 61 l. 15 . 43 2. 67 . 155 3. 92 25. 3 31. 3 g . 1765 7, 530 42, 550
219 ___ ___________ ---- ·---- 3)1 . 018 4. 25 1. 21 . 37 3. 24 . 133 4. 14 31. 0 18. 3 g . 0978 3, 550 36, 200
220 __ __ --------------- --- 3)1 . 018 4. 15 1.18 .41 2. 88 .148 3. 82 25. 8 17. 1 g . 0990 3, 280 33, 100 221 ___ ___ ______ ___________
3),\! .018 4. 27 1. 22 . 38 3. 24 . 137 3. 78 27. 6 16. 6 g . 0972 2, 560 26, 300
217 _______ -- 4 . 012 4. 78 1.19 . 40 2. 97 .144 5. 44 38. 8 18. 3 g . 0745 2, 380 31, 900
218 .. __ ____ - .: :: · -- --· ----
4 . 012 4. 86 1. 21 . 40 3. 02 . 144 5. 40 37. 5 18. 5 g . 0756 2, 330 30. 800
218-A ___________ : ::: : : : :: 4 . 012 4. 84 1. 21 . 40 3. 02 .144 5. 43 37. 7 18. 4 g . 0750 2, 470 32. 900
214 _______ 3)1 . 019 4. 20 1. 20 . 41 2. 93 . 148 6. 17 41. 7 27. 9 g .1000 3, 640 36, 400
215 ____ - -- .::::::::: :::: :: 3),\! . 019 4. 28 1. 22 . 43 2. 84 . 155 5. 75 37. 0 26. 6 g . 1023 3, 760 36, 700
216 _______ 3),\! . 019 4. 25 1. 21 . 43 2. 82 . 155 5. 95 32. 0 26. 8 g .0995 3, 660 36, 800
211... ______ :::::::::::::: 4 . 031 4. 70 1. 17 . 41 2. 85 . 148 5. RS 38. 4 45. 8 g . 1780 7, 510 42, 200
212 _______________________ 4 . 031 4. 73 1. 18 . 40 2. 95 .144 5. 90 41. 0 47. 9 g . 1791 7, 000 39, 000
213 __ ___________ _________
3H . 031 4. 00 1.15 . 41 2. 81 . 148 5. 98 40. 4 41.9 g . 1548 6, 550 42, 300
20s ___ __ __________ ________ 3J.1; . 019 4. 28 1. 22 . 39 3.12 . 140 7. 89 56. 3 36. 3 g . 1015 3, 780 37, 200
209. __________ ___________ _ 3J.1; . 019 4. 25 1. 21 . 40 3. 02 . 144 7. 91 55. 0 36. lg . 1008 3, 590 36, 600 210 ______ ________ _________
3),\! . 019 4. 25 1. 21 . 40 3. 02 . 144 7. 76 54. 0 35. 2 g .1002 3, 670 36, 600
205. __ ____ ____ -- - - ------ - - 4 . 031 4. 66 I. 17 . 40 2. 92 .144 8. 02 55.6 65. 0 g . 1790 6, 760 37, 800
206 ____ __ __ ____ ---------- - 4 . 031 4. 75 1.18 . 43 2. 75 . 155 8. 06 52. 3 66. 3 g . 1812 7, 385 40, 600
207 ______________ _________ 3),\! . 031 4. 28 1. 22 . 41 2. 98 . 148 8. 04 54. 3 66.3 g .1820 7, 030 38, 800
202 _____ ------- - ---- - -- - - - 4 . 013 4. 81 1.19 . 40 2. 98 . 144 8.18 56. 9 28. 3 g . 0765 2, 170 28, 400
203 ______ _____ _________ ___
4 . 013 4.86 1. 21 . 40 3. 02 . 144 8.U 57. 2 28. 6 g . 0767 2, 270 29, 600
204 ____________ __________ _ 4 . 013 4. 8C 1. 21 .39 3.10 . 140 8. 08 57. 7 28. 0 g . 0765 2, 320 30, 300
199 __ _______ ___ __ ____ _____
4 . 0125 4. 85 1. 21 . 40 3. 02 . 144 9. 94 69. 0 34. 3 g . 0764 2, 130 27, 900
200 ___ ______ ___ ____ ______ _
201_ ___ ___ ____ ____ ___ _____ 4 . 012 4. 84 1. 21 . 40 3. 02 .144 9. 97 69. 2 34. 4 g . 0763 2, 350 30, 800
3)1 . 012 4. 18 l. 20 .40 3. 00 . 144 9. 94 69. 0 30. 6 g .0680 2, 110 31, 000
196 __ ____ ____ ___ __ __ ___ ___
4 . 0315 4. 70 1.17 . 43 2. 72 . 155 12. 04 77. 7 101. 8 g .1860 5, 710 30, 700
197 __ ___ ______ ____ ___ ____ _ 4 . 0315 4. 70 1. 17 . 43 2. 72 . 155 12. 05 77. 8 JOO. 3 g . 1840 5, 850 31, 800
198 __________ ____ _____ - - -- 4 : 0315 4. 70 1. 17 . 43 2. 72 . 155 12. 06 77. 9 100. 8 g . 1845 5, 580 30. 200
193 ___ ___ _____ ____ ___ - - --- 4 . 013 4. 84 1. 21 . 41 2. 95 . 148 11. 93 80. 6 41. lg . 0762 2, 270 29, 800
194. ____ ___ _______ _____ ___ 4 . 013 4. 89 1. 22 . 41 2. 97 . 148 12. 01 81. 2 42. 3 g . 0777 2, 250 29, 000
195 ____ __ ______ _____ ______ 4 . 0125 4. 87 I. 22 .40 3. 05 .148 11. 96 80. 7 H.5g . 0767 2, 250 29, 300
190 _____ ___ _____ ____ ___ __ _
4 . 0125 4. 90 1. 22 . 40 3. 05 . 144 13. 90 96. 5 48. 5 g . 0770 2, 160 28,000
l9L ____ _________ ___ ____ __ 4 . 0125 4.88 1. 22 . 42 2. 90 . 151 13. 78 91. 2 49. 3 g . 0792 2, 160 27, 300
192 ____________ __________ _ 4 . 0125 4.81 1. 22 . 41 2. 98 .148 13. 82 93. 5 48. 3 g .0772 2, 260 2Q, 300
15
TABLE IL-Corrugated dural sheet tested as fiat-ended columns
IM depth- 2).2 pitch- Fixed edges]
Num-ber
Width Pitch Depth p Test no. corru- t w p D p Length -L Weight
gations (in.) (in.) (in .) n L (in.) p
n . --------- ------ ------------
228 ___ ___ - ---- -- - -- --- --- - 4 0.013 11.3 2. 82 0. 77 3. 66 0. 281 3. 98 14. 2 31.3 g
229 ___ __ - - -- - - - -- - - -- - - -- - 4 . 0125 11. 56 2. 89 - 71 4. 07 . 256 3. 94 15. 4 29. 8 g 230 ___ ___ ____ ___ _______ _ --
4 . 012 11. •17 2. 87 . 73 3. 93 . 262 3. 95 15. 2 29.8 g
231. .. -- ----- -- - - - -- - -- - - - 4 . 0125 11. 5 2. 88 . 69 4.17 . 244 5. 96 24. 4 47. l g
232 ___ - ---- -- -- ---- --- --- - 4 . 0125 11.28 2.82 . 76 3. 72 . 274 5. 9fi 21. 7 45. 4 g
233 .... - - ---- ------ ---- --- 4 . 0125 11.40 2. 85 . 73 3. 90 . 263 5. 95 22. 6 45.0 g
123 ••• -- -- ----- - - . - ------ - 4 . 024 11. 38 2. 84 .7fi 3. 79 - 270 3. 95 14. G 57. 9 g
124 ... - - - - ----- -- - -- -- - -- - 4 . 024 11. 25 2. S2 . 74 3. 81 . 267 3. 92 H.7 56. 7 g
112 __ ____ ----- ------------ 4 .024 11. 27 2. 82 . 75 3. 76 . 270 5. 97 22. l 87. 6 g
113 ___ --- - - - -- -- ---- -- -- - - 4 . 024 11. 23 2. 81 . 75 3. 74 . 270 5. 90 21. 8 82. 6 g
114 ___ -- - - -- . - -- ---- -- -- -- 4 .024 11. 45 2.86 . i5 3. 81 . 270 5. 95 22.0 85. 6 g
126 .• --- ----------------- 4 .049 11.03 2. 76 .SI ~.10 . 291 4.00 13. 7 117. 8 g
1!2278 - -_-__--__--__-_-_-_-_- -_- -- -- - - -- - - 4 . 049 11.00 2. 7!\ . 3 1 3. 40 .2Pl 4. 00 13. 7 lt7. 4 g - - --- - -- 4 . 043 11. 05 2. 76 . 81 3. 40 . 291 -1. 02 n8 118. 0 J?
ll5 ______ __ - - --- -- --- --- . 4 . 050 10. 90 2. 73 . E2 3. 33 . 294 6. 02 20. 4 183. 0 g
116 _____ ----- - ----------- 4 .050 10. 84 2. 71 . 81 3. 35 . 291 5. 96 20. 5 181. 35 l?
117 ___ -- -- -- - - -- --- - --- -- - 4 .050 10. 98 2. 75 .84 3. 28 . 301 6. 02 20. 0 1~3- 95 g
38 ___ ---------· 4 - 012 11. 48 2.87 . 75 3. 83 .270 9. 97 31\.9 79. 7 g
35 ____ _ -- - -- -- - -- -- -- - - - - -- 4 . 024 11. 18 2. 80 . 7o 3. 73 . 270 10. 08 37. 3 148. 7 g
3~L ______ _____ -- -- ------ 4 . 050 JO. 3•1 2. 59 .82 3. 16 . 296 10.10 34.1 304. l g
556L .• --_-__- -_- - - - -- -- -- - - ----- - 4 . 012 11. 45 2.86 ---- --- -- -- --- --- ------ -- 16. 88 63. 0 ----·----- --- - - -----------1 4 . 024 ll. 10 2. 77 . 72 3. 85 . 2.o9 17. 10 66. 0 ---·----- - fi2 __ -- - - - .. - -- .. -- -- - -- -- -- I ·1 .050 10. 93 2. 74 . 80 3.42 - 287 17. 10 53. 5 --- --- ---- 78 ___ __ -- - --------- -- -- --- 4 . 012 11. 53 2.88 . 70 4. 12 . 252 lG. 95 67. 2 136. 3 g
79 ______ .. - - -- . -- - -- -- - --- - 4 . 024 11. 15 2.80 . 75 3. 74 . 270 17. 15 63. fi 252. 2 g
81044 . ._ -_-__-_._ - - -- - - -- - -- - - - -- - - 4 .050 10. 90 2. 73 . 83 3. 30 .298 17.13 57. 5 520. 5 g ---·----- -------- 4 .012 11. 37 2. 84 . 74 3. 83 . 266 26. 07 98.0 .437lb.
i4.,5 ___ - --- - -- -- ·--- --- -- -- - 4 .012 11.42 2.86 . 75 3.82 . 270 26. 00 96. 3 .424 lb.
141\ ____ - - - -- - - -- - -- - - -- --- 4 .012 11.45 2.86 . 75 3. 82 . 270 26. 04 96. 5 . -157 lb.
157. ___ ________ _ ---- --- ---- 4 .025 11. 31 2. 59 • 74 3. 'iO . 266 26. 07 98. 0 .880 lb.
1.58 ____ --- ----- -- .. ---- --- 4 . 025 11. 30 2. 59 . 76 3. 4 l . 273 26. 04 95. 5 .880 lb.
159 .. ------- ------------- 4 . 025 11. 42 2. 86 • 75 3. 82 . 270 26. 14 96. 8 . 891 lb.
11666j ____ -- - - - -- -- - - -- - - - - - - 4 . 0.12 11. 00 2. 75 . 80 3. 44 . 287 26.13 91. 0 L 789 lb. ______________ _____ ___ - 4 . 052 11. 01 2. 75 . 81 3. 40 . 291 26. 04 89. 5 1. 806 lb.
lf.S _______ -- - ----- - -------- 4 . 052 ll. ()() 2. 75 . 80 3.44 . 287 25. 97 90. 5 l. 765 lh.
96 . • - - -- -- -- --- - - ------- -- 4 . 012 11. 56 2.89 . 67 4.30 . 242 9.88 40.8 79. 2 g
97 ___ ---- -- - -- --- -- - ---- -- 4 . 050 10.87 2. 72 .so 3. ·JO . 287 10. rn 35. 3 303. 8 g
44 ... - ---- --- ---- --- --- --- 6 . 012 16. 94 2.82 . 72 3.90 . 259 10. 00 38. 6 110. 6 g
42 ____ -- -- - ---- - - - ----- - - - 6 .024 16. 95 2.82 . 70 4.03 . 253 10. 05 39. 7 214. 7 g
94 ____ -- - · - - - -- - ----- - -- -- 6 . 024 16. 91 2.82 . 74 3.81 . 266 10.10 38. 0 214. 85 g
40 ______ __ .. -- ---- --- -- - -- 6 . 050 16. 33 2. 73 .80 3. 41 . 287 10. 08 35. 4 440. 4 g
95 ___ -- .. - - - -- - - - - - -- ------ 6 . 049 16. 45 2. 74 .80 3. 41 . 287 10. 04 35. 0 440. 2 g 62 ___ _____ _______ ----- --- 6 . 012 17. 08 2. 84 . 70 4.06 . 2<i3 17. 05 67. 4 190. 8 g
81_ ____ ----- - -- - . - ---- -- - - 6 . 012 17. 05 2. 84 . 70 4.06 . 253 17. 07 67. 4 190. 0 g
60 ••. - - - ------ - --- -- - - - - - - 6 . 02-1 16. 98 2. 83 • 75 3. 77 . 269 17. 10 63. 5 361. 5 g
82 ______ ________ - ---- -- - -- 6 . 024 16. 93 2.82 71 3. 97 . 256 17. 15 67. 0 364. 8 g
58 __ __ .. ---- - -- --- - - -- - - -- 6 . O.'iO 16. 40 2. 73 .80 3.41 . 287 17. 17 59. 8 750. 0 g
83 __ - - - - - - - - - -- -- - -- - - - .. - 6 . 050 16. 33 2. 73 . 81 3. 37 . 291 17. 15 fi9. 0 748. 5 g
l5L. - --- --- -- - -- ------- - - 6 .012 17. 57 2. 93 . 66 4. 44 . 238 26. 04 109. 0 .652 lb .
152 ___ - -- - -- --- - --- - ----- 6 . 012 17. 43 2. 9l . 67 4. 34 . 242 26. 00 107. 0 .652 lb .
153.. __ ---- --- --------- -- 6 .012 17. 44 2. 91 . 68 4. 28 . 246 2.1. 91 105. 0 .649 lh. . 160 __ _________ _____ _____ _
6 .0245 17.09 2.84 • 77 3. 69 . 276 26. 09 95. 0 1. 297 lb .
r1n62L __________ _--_- . -... -__- -__- -__-_- -_-__- -- -- 6 . 025 16. 91 2.82 . 75 3. 76 • 269 26.08 97. 0 1.307 lb. 6 .025 17. 02 2.84 . 75 ~- 79 .269 26. 01 97. 0 1. 292 lb.
169 . . ... -- - ------ -- - -- ---- - 6 . 051 16. 46 2. 74 . 79 3. 46 . 284 26. 03 92. 0 2. 611 lb .
170 ___ -- -- -- ------ ------- 6 . 050.5 16. 48 2. 71 . 81 3. 38 . 291 25. 96 89. 0 2. 606 lb.
171. __ ---- --- - -- - - ----- - -- 6 .0505 16.45 2. 74 . so 3. 42 . 287 26.00 91.0 2. 613 lb .
234 ____ . - --------- - -- --- --- 6 . 012 17. 60 2. 94 . 66 4.46 . 238 6.02 25. 3 68. 8 g
235 ___ _______ ------ ------- 6 .012 17. 44 2. 91 . 67 4. 35 . 241 6. 01 24. 9 68. 1 g 236 __ ___ ____ ___ -- - -- - --- -- 6 . 012 17. 40 2. 90 . 71 4.09 . 256 6.12 23. 9 69. 4 g
237. ____ ___ __ -- - ---- - - -- - . 6 .0245 17. 03 2. S4 . 75 3. 92 . 270 5. 63 20. 8 127. 3 g
237 ___ ---- -- -- - - -- ---- - - -- 6 .0245 17. 03 I 2. 84 . 75 3. 92 . 270 5. 63 20.8 I 127. 3 g
26L ____ -- . - -- - ----- -- -- - - 6 . 0245 17. 08 2. 85 . 73 3. 90 . 262 5. 49 21. 0 123. 8 g
262 •• • - - -- - - -- --- - - - - - - - - - 6 . 0245 17. 03 2.84 . 73 3. 89 . 262 5. 60 21.4 126. 4 g
249 _____ -- - - -- - - - - - -- --- - - 6 . 0245 17. 05 2. 84 . 75 3. 92 . 270 3. 93 14. 5 88.3 g
2.10 ... - - - - -- - -- - - -- - - -- - - - 6 . 0245 16. 95 2. 82 . 73 3. 87 - 262 3. 96 15. 2 90. 1 g
25L ___ ___ . -- - - - - - - -- - - --- 6 . 0245 16. 95 2.82 . 74 3. 81 . 266 3. 81 14. 3 85. 5 g
252 . . . -- -- - -- ---- - - - -- - - - - 6 . 0505 16. 47 2. 75 . 83 3. 32 . 299 3. 86 12. 9 175. 5 g
253 .. . -- -- -- - - - - -- - - - - - - - - 6 . 050 16.48 2. 75 . 77 3. 57 . 277 3. 96 14. 3 li9. 8 g
254 ___ -- -- -- - - - - - - -- - - -- - - 6 . 0505 16. 44 2. 74 . 79 3. 47 . 284 3. 52 12. 4 160. 2 g
255 __ _ -- - - -- -- - - -- -- -- -- -- 6 . 012 17. 42 2. 90 . 63 4. 60 . 227 3. 55 15. 7 40. 2 g
256 .•. - - -- - - --- - ----- - ---- 6 . 0125 17. 75 2. 96 .58 5.10 . 209 3. 54 16. 9 40. 2 g
257 __ - - -- -- - ------- -- -- -- 6 .012 17.45 2. 91 . 70 4.16 . 252 3. 53 14. 0 39.9 g
258 ••• -- ---- . --- - ---- - ---- 6 .0505 16. 47 2. 91 . 80 3. 64 . 288 5. 72 19. 7 260. 8 g
260 ••• -- . - -- - ----- - - ------ 6 . 0505 16.48 2. 91 . 81 3. 59 . 292 5. 79 19. 8 262. 8 g
3L. - - __ -- - --- - --- -- ------ 2 .012 5. 68 2. 84 . 72 3. 94 . 259 10. 05 38. 8 35. 6 g
98 .. - - --- --- -- -- -- -- - - - - -- 2 .012 5. 75 2. 87 .68 4. 23 . 245 10. 06 41.0 36. 0 g
29 ... - ------------- - ------ 2 .024 5. 50 2. 75 . 73 3. 77 . 263 10. 08 38. 3 73. 6 g
99 _____ - -- - --- ------ - - - - -- 2 - 024 5. 45 2. 72 . 74 3. 67 . 267 I0. 07 37. 5 72. 8 g
27 __ __ --------- - ----- ------ 2 . 050 5. 51 2. 75 .. 80 3. 44 . 288 10. 05 35. 0 149. 3 g
100 ... - ----- - - - - - -- -- - - - -- 2 . 050 5. 53 2. 76 .80 3. 45 . 288 10. 10 35. 1 152. 0 g
50 ... - - - -- -- - - - - - -- - - -- -- - 2 . 012 5. 72 2. 86 ----- --- --- ----- . 252 17. 06 67. 0 61. 6 g
75 _____ ------------ -- ---- - 2 . 012 5. 60 2.80 . 70 4. 00 . 252 17. 10 67.5 60.1 g
48 •. -- - - - -- -- - - - - - - - - - ---- 2 . 024 5. 60 2.80 . 77 3. 64 . 277 17. 15 61. 5 126. 7 g
76. -- - -- - - -- - - - - - - - - - - - - - . 2 . 024 5. 60 2. 80 . 77 3. 64 . 277 17. 10 61. 5 128.1 g
46 ... - - -- - - - . - - - -- - - -- -- -- 2 . 050 5. 47 2. 73 ---- --- --- ---- -- . 288 17. 10 60. 0 258. 6 g
77 ____ -- ·-- ---- - ----- -- - - - 2 .050 5. 46 2. 73 .80 3. 41 . 288 17. 15 59. 3 261. 5 g
147 ___ - - - - - --- -- - -- --- ---- 2 .012 5. 82 2. 91 .68 4. 28 • 245 25. 90 106. 0 93. 7 g
148 .. . - ---- - --------- - -- -- 2 . 012 5. 81 2. 90 . 70 4.14 .252 25. 72 102. 0 92. 3 g
150. -- .. - - - - - - - - -- - -- -- -- - - 2 . 012 5. 85 2. 92 . 70 4.17 . 252 25.80 102. 0 93. 7 g
154 ••• - -- -- - -- -- -- -- -- -- -- 2 . 024 5. 59 2. 79 . 75 3. 99 . 270 26.10 97. 0 191. 2 g
155 .. - -- -- - - - . - - - - - - -- -- - - 2 . 024 5. 67 2. 83 . 75 3. 78 . 270 26.14 97. 0 191. 2 g
Area A Load
p
(sq. in.) (lb.)
- -----
0. 1727 2, 430
. 1670 2, 590
. 1670 2,430
. 1740 2, 150
. 1680 2.060
- 1670 2, 230
. 3233 8, 100
. 3200 7, 930
. 3245 9, 410
- 3095 8, 250
. 3180 9, 980
. 650 26, 970
. 649 25, 400
.619 26, 250
. 674 25, 810
.672 29, 740
. 675 29, 330
. 1768 3, 560
. 3260 8,835
. 666 27, 990
.176 3, 510
. 324 10, OliO
- 705 25, 410
. 1778 3, 350
. 3250 9, 280
. 659 25, 470
.1680 2, 150
. JG71 2.130
. 1755 2, 410
. 3385 9, 230
. 3385 8, 150
. 340 9, 650
. 685 20, 660
. 695 20, 760
. 683 21, 340
. 1770 3, f,80
. 662 26, 460
. 2440 3,160
.473 13, 660
. 470 13, 010
. 966 36, 900
.939 32, 320
. 2470 4, 100
. 2465 3, 920
. 474 13, 050
. 470 13, 810
. 971 33, 400
. 965 34, 960
. 2505 2, 970
. 251 2, 770
. 251 2, 610
. 495 13, 470
.501 13, 170
.495 11, 030
1.005 26, 920
1.010 27, 620
1. 005 28, 060
- 253 2. 890
. 250 2,400
. 250 2, 600
. 500 15, OliO
.500 15, 060
. 498 15, 250
. 498 14, 000
. 496 12, 500
. 504 12, 450
. 496 12, 820
l. 005 41, 480
l. 003 41, 340
1.009 41, 070
. 250 3, 650
. 251 3, 400
. 250 3, 320
1. 009 40, 240
1.001 39, 330
. 0783 1, 570
. 0792 1, 220
- 1619 5, 550
. 1600 4, 640
. 3285 13, 770
. 332 13, 000
. 0799 1, 610
. 0776 1, 150
. 1630 5, 170
. l656 4, 750
. 334 12, 990
- 336 12, 425
. 0799 I, 130
. 0794 l, 150
. 0804 l, 100
.1620 4, 230
. 1617 4, 260
p
A
(lb./
sq. in .)
---
14, 100
15, 500
14, 600
12, 300
12, 250
13, 350
25, 100
24, 800
29, 000
26, 650
31, 400
41.400
39, 200
40, 500
38, 100
44, 200
43, 500
20, 200
28,8 00
42, 00 0
000
000
000
20,
31,
36,
18, 900
28, !\00
40,
12, 80
200
0
12, 70 0
13, 600
27, 200
24, 00 0
28, 400
30, 2 ~0
29,80 G
0
0
0
0
31, 20
20,80
40, 00
14, 20
28,8 no
0 a
00
0
27, 70
38, 20,
33, 4
16, 60
15, 9 00
00
0
0
27, 4
29,10
34, 40
35,
11, 8.5
2oO
0
0
0
0
0
11,05
10. 40
27, 20
26, 80
22. 2
26,80
00
0
0
0
27,40
27, 90
11, 4
9, 6
10, ·!O
00
00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
30.12
30, 12
30, 60
28, 10
25, 20
24, 75
25,80
41. 25
41, 20
40, 80
14,60
13, 55
13, 25
39, 90
39, 20
20, 10
15,40
34, 30
29, 00
41, 90
39, 20
20, 10
14, 80
31. 60
28, 70
38, 90
37, 00
14, 15
14, 50
13, 70
26, 10
26, 35
16
TABLE II.-Corrugated dural sheet tested as flat-ended columns- Continued
Num-ber
Widtb Pitch Depth p Test no. corru- l w p D Length L 15 p L(in.) - Weight
gations (in.) (in.) (in .) p
n - -- --- --- --- ---- ------ -----
156 __________ ____________ _
163 ___ ___ _________________ 2 0. 024 5. 75 2. 87 0. 75 3. 83 0. 270 25. 98 96.0 191. 3 g
164 ____________ ___________ 2 • 051 5. 55 2. 77 . 80 3. 46 . 288 26. 07 91.0 . 886 lb.
165 _____ ____ ____ _______ ___ 2 .051 5. 55 2. 77 .80 3. 46 . 288 26. 06 91. 0 .889 lb.
23g _________________ ___ __ _ 2 . 051 5. 52 2. 76 . 82 3. 37 . 295 26. 07 88. 5 . 885 lb.
239 _____________ __ ________ 2 • 024 5. 69 2.84 . 73 3.89 . 263 9. 97 37. 9 73. 1 g
240 ___________ __ _____ ____ _ 2 .024 5. 75 2.87 . 72 3. 99 . 259 9. 71 37. 5 72. 0 g 24L _________ _____________ 2 . 012 5. 81 2. 90 . 72 4. 03 .259 9. 96 38. 4 36. 2 g
242 _____ _________________ 2 . 012 5. 75 2. 87 . 75 3. 83 . 270 9. 92 36. 7 35. 6 g
2 . 012 5. 78 2. 79 • 78 3. 58 . 281 15. 71 56. 0 57. 3 g
243 ___ --------- - ------- - -- 2 . 024 5. 68 2. 84 . 75 3. 79 . 270 15. 80 58. 5 115. 8 g
TABLE III-;-Corrugated dural sheet tested as flat-ended coliimns
[l ).i depth- 3% pitch-fixed edges]
Num-ber
Width Pitch Depth p Length L T est no. corru- l w p D ]5 p L (in .) -
gations (in.) (in.) (in.) p
n --- ------ --- --- ---------
120 ___ ____________________
4 0.012 16. 40 4.10 o. 95 4. 32 o. 343 4.00 11. 6
11222L _-_-_-_-_-__-_-_--__-_--_-__-_-_-_-_-_-_-_-_- 4 .012 16. 45 4.12 .90 4. 57 . 327 3. 87 11. 8
ll8 ____ _____ ___________ ___ 4 • 012 16. 60 4. 15 . 90 4. 62 . 327 3. 74 11. 4
119 __ ________ _______ ___ ___ 4 . 031 16.00 4.00 . 90 4. 45 . 327 3. 97 12. 1
187 ______ ___ ____ ___ __ _____ 4 . 0305 16. 27 4. 06 . 90 4. 51 . 327 3. 96 12. 1
188 ________ _______________ 4 . 081 15. 18 3. 79 1. 01 3. 75 . 364 3. 58 10. 1
189 __ __ ___________________ 4 . 081 15. 15 3. 79 1.00 3. 79 . 364 3. 58 10. 0
106 __ ___ _____ _____________ 4 . 081 15. 09 3. 77 . 96 3. 94 . 364 4. 00 11. 0
4 . 014 16. 60 4.15 . 9,5 4. 37 . 34.2 7. 87 23. 0
110073 ________ _- -__-_-_-_--__-_-_-_- -__- _-_-_-_- -__- 4 . 013 16. 65 4.17 . 92 4. 53 . 333 7. 87 23. 6
104 ____________________ ___ 4 . 032 15. 89 3. 97 . 93 4. 27 • 335 8. 00 23. 8
105 _____ __________________ 4 . 032 15. 08 3. 76 . 95 3. 96 . 342 8. 00 23. 4
184 _______ __ _______ _______ 4 . 032 16. 00 4.00 . 91 4. 40 • 329 7. 96 24. 2
4 . 081 15. 36 3.84 . 97 3. 96 • 350 7. 91 22. 6
185 .... - - ------- -------- --- 4 . 081 15. 53 3. 88 1. 04 3. 73 . 374 7. 92 21.0
186 _____________ __ ______ __ 4 . 081 15. 40 3.85 ]. 01 3. 81 . 364 7. 90 21. 7
68 ________________ __ ______ 4 . 012 16. 46 4.12 . 94 4. 38 . 339 12. 20 36. 0 66 _______ ________ _________
4 . 030 16.10 4.02 .95 4. 23 . 343 11.88 34. 6
18L. _____________________ 3 . 031 12. 05 4.02 . 90 3. 75 . 324 12. IO 37. 4
182 ______________________ 4 . 080 15. 07 3. 76 1.04 3. 52 . 374 12. 02 32. 0 183 ______________ __ _______
74 ___ , ____________________ 4 . 080 15. 03 3. 76 . 98 3. 84 . 352 12.10 34. 5
142 _______________________ 4 . 012 16. 28 4. 07 ------- - -------- . 326 23. 98 74. 0
3 . 032 12. 75 4. 25 .90 4. 73 . 326 24.10 74. 0
72 ______________ __ ________ 4 . 030 16. 00 4.00 -------- -- ------ . 326 23. 82 74. 0 143 _________________ ______
70 ________________________ 4 . 080 15.10 3. 78 . 98 3. 86 . 353 24. 00 68. 0
4 . 080 15. 13 3. 79 . 97 3. 91 . 349 24. 00 69. 0
172 ________ --- ----- ------ 4 . 0135 16. 40 4. 10 . 96 4. 27 . 346 36. 00 104. 0
,73 _____ __ -------------- - - 4 . 012 16. 41 4. 10 . 92 4. 46 . 333 36. 10 108. 5 174 _____ __________________ 175 _______________________ 4 . 013 16. 54 4. 14 . 93 4.15 . 336 35. 91 104. 0
3 . 031 11. 85 3. 95 . 90 4. 38 . 325 36. 06 108. 0
176 __ ____ __ ____ __ ________ 4 . 031 15. 82 3. 96 . 90 4. 40 . 325 36.13 108. 0
177. ______________________ 4 . 031 16. 00 4.00 . 94 •1. 26 . 339 35. 94 103. 0 178 __ ___________ ________ __
179 ___ _________ __________ _ 4 . 081 15. 12 3. 78 1. 01 3. 75 . 364 36. 10 99. 0
4 . 081 15.15 3. 79 . 99 3. 83 . 357 36.11 101. 0
180 _____ _________ _________ 4 . 081 15. 05 3. 76 . 95 3. 96 . 376 36. 16 96. 0 246 _______ ____________ ____
247 ______________________ 4 . 013 16. 37 4. 09 . 96 4. 25 . 346 20. 71 59. 3
241J _______ , ___________ ____ 4 . 013 16. 43 4. 12 . 97 4. 24 . 349 20. 76 59. 5 4 . 013 16. 50 4. 12 . 97 4. 24 . 349 18. 64 53. 5
TABLE IV
Num-ber
Width Pi tch Depth p Length L Test no. corru- t w p D 15 p L - Weight
gations (in.) (in .) (in .) (in .) p
ll
---- - - --- --- --- ------------
6 __ ___ ____ _ - 6 0.019 7. 00 ]. 16 0 . .I Q 2. 90 0. 143 8. 00 56. 0 58. 0 g 7 ___ _____ ______
6 . 019 6. 98 l. 16 . +o 2. 90 . 143 8. 03 56. 0 5.Si. 1 ~
0 .. ---··-----··-. 6 . 019 7. ()() 1. 16 . 40 2. 90 . 143 7. 95 55. 6 -------- -·
2221 ._ ________ _-_-·_ _·_-_-_-_- 6 . 019 7. 17 1.19 . 3S 3. 14 .136 21. 02 154. 5 -- --------
244 ____________ 6 . 0 19 7. 17 1. 19 . 38 3. 14 . 136 21. 02 154. 5 -----··----
19 _____________ 6 . 019 6. g; J.16 . 39 2. 98 . 13\> 21. 05 155. 5 158. 6 g
6 . 032 6. 88 l. 15 . 38 3. 03 . 135 20. 98 154. 0 -- ------- -
20 ..... ------ -- 6 . 032 6. 88 !. I ii .40 2. 88 . 143 21. 16 14.8. 0 ----·----·
245 _____ ------- 6 . 032 6. 95 1. l6 . 40 2. 90 . 1-13 21. 02 ] .\7. 0 265. 5 ~
86. ------------ 6 . 012 7. 15 l. IV . 38 3. 14 . 136 13. 85 102. 0 72. 0 g
8960 _'_·_-_-_-_-_- ------ 6 .013 7. 15 1. 19 . :is 3. l ·l . 136 13 85 102. 0 72. 0 g 6 . 012 7. 12 1.18 . 39 3. 03 .HO 9. 95 71. 0 51. 2 g
90 '-- ---·--- ·- - 6 . 012 7. 12 1. 18 . 39 3. 0;1 . 140 9. 96 71. 0 5 1. 2 g
92. __ ·--------. 6 .012 7. 20 1. ~!() . 40 3. or . 143 10. 00 70. 0 51. 5 g
92 '-- ----· -- -· - 6 . 0 12 7. 20 l. 20 . 40 3.00 . 143 10. OIJ 70. 0 51. 5 g
110 ____ ---- ---- 6 . 031 6. 89 1. 15 . 40 2. SR . 143 5. 94 4 1. 5 71. 2 g
110 ' -------- · · 6 . 031 5. SP 1. 15 . 40 2. 88 . 143 5. 94 II. 5 71. 2 g
I Specimens railed origina lly in buckling.
2 Row of rivets, one to each corrugation, I incb from end . Buck led at center and not at ri vets.
a Specimen failed originally in column heading.
•Rivets in eacb corruga tion, at center and ! inch rrom end. F ailed in column bending.
' First failure in buckling.
' Retest after straigh tening. Did n ot fail at point or original Cailure.
' Failure in column bending.
Weight
- --
46. 2 g
39. 55 g
38.0 g
102. 2 g
98. 9 g
228. 9 g
230. 2 g
257. 9 g
96. 6 g
86. 2 g
205. 0 g
209. 9 g
204. 0 g
517. 2 g
525. 4 g
525. 7 g
------- ---
305. 8 g
236. 0"
762. 6 g
762. 4 g
271. 86 g
!. 093 lb .
613. 06 g
3.3521b.
1, 508. 0 g
.951 lb.
.836 lb.
.859 lb.
l. 525 lb.
2. 011 lb.
2. 055 lb .
5. 108 lb.
5. 081 lb.
5. 026 lb .
249. 5 g
219. 3 g
210. 6 g
Area
A
(SQ. in .)
---
0. 1600
. 16<Xl
. 1500
. 1640
. 1640
. 16'10
. 278
. 278
. 278
. l 15
. 115
. 1134
. 1134
. 1138
• l 138
. 26.56
. 2651\
AreaA Load
(sq. in .)
p
(lb.)
------
0. 1628 4, 220
. 340 11, 875
. 341 11, 710
. 340 '" 10, 530
.1620 4, 670
.1603 4,840
. 0851 1, 200
. 0794 1,200
. 0805 1, 635
.1619 4, 850
AreaA Load
(sq. in. )
p
(lb.)
-------
o. 2550 2, 560
. 2255 2, 150
. 2250 1, 750
. 570 12, 670
. 552 12, 470
1. 415 56, 000
1. 422 47, 130
l. 424 52, 180
. 2715 3, 550
.2420 3, 250
. 567 15, 310
. 529 12, 760
. 566 14, 54.0
1. 445 61, 810
1. 47 59, 150
1. 47 56, 850
. 2254 2, 400
. 568 16, 040
. 431 12, 800
1. 405 54, 330
1. 395 57, 000
. 2230 3, 730
. 450 10, 150
. 566 14, 730
l. 400 45, 460
1. 389 43, 830
. 2575 3, 240
. 226 2, 500
. 2395 2, 360
. 420 10, 890
. 5575 13, 540
. 560 14, 320
1.420 36. 210
1. 410 35, 920
1. 390 35, 470
. 266 2, 960
. 226 4. 710
. 250 2, 700
Load p
p A
(lb .) (lb./sq.in.)
------
5, 940 3. 700
5, 970 37. 250
6, 100 3~. 100
2, 5'50 15. 600
2, 560 !5, 6('0
2, 900 17, 700
5, 110 18. 400
4, 610 16, 600
•J. 660 16, 7ii0
3, 000 26, 100
2, 710 23. 550
3. 500 30, 800
2, 660 n.400
3, 520 30, 900
2, 380 2~ . 650
10. 670 40. 100
10, 100 38, 000
p
A
{lb ./
sq. in.)
---
25, 900
34, 9 00
00
0
0
0
0
0
0
0
34, 4
31, 00
28,80
30, 10
14, 10
15, 10
20, 30
30, 00
p
A
(lb./
sq. in.) ---
10, 050
9, 550
7, 700
22, 200
22, 550
39, 500
N . G.
N . G .
13, 100
13, 400
27, 000
24, 100
25, 700
43, 400
40, 250
38, 000
10, 700
28, 200
29, 700
38, 600
40,800
16, 700
22, 600
26, 000
32, 200
31, 600
12, 600
11, 100
9,870
25, 90<J
24, 300
25, 600
25, 500
25, 500
25, 500
11, 100
20, 800
10, 800
Percent
of origi-nal
load
---
(')
(')
(')
(')
(')
(' )
(')
(')
('J
(•)
6 90
(')
576
(')
6 67
Ul
' 9.1
17
TABLE V.-Corrugated dural sheet tested as p·in-ended columns
[% depth- 1 H pitch]
FREE EDGES
Test no.
Nbuemr - Width Pitch Depth p I L Area A Load Ap
corru- W P D A p z~n(~h) Weight ( Q · ) P (lb I
gations (in.) (in.) (in .) P s · In. (lb.) . sq .
28_3 __- __-_- __-_- __-_- __-- _-_-_- __-_- ___ , __"_ · _4 ~~~~.~~~1~~- 0. 0746--750 i~o'.ooo
284 ___ _____ __ _________ ____ 4 . 012 4. 75 1.19 . 38 3.14 . 137 15. 60 111. 0 48. 0 g . 0757 555 7, 340
285_______________________ 4 .012 4. 73 1.18 .39 3.03 .140 15.60 109.0 46.9 g .0740 525 7, 100
266__________ _____________ 4 . 012 4. 75 1.19 . 39 3. 05 .140 13. 28 95. 0 40. 3 g . 0764 2, 244 11, 000
268___ __________________ __ 4 .012 4.77 1.19 . 37 3.21 . 133 13.38 101.0 40.7 g .0765 1,565 8, 000
269_______ ____ _________ ___ 4 .012 4.79 1.20 . 39 3.08 .140 11.32 81.0 34.6 g .0786 1, 210 15, 400
270_______ ______ _________ _ 4 .012 4.79 1.20 .39 3.08 . 140 11.36 81.0 34.4 g .0779 1,080 13, 200
271__ ___ ______________ ____ 4 .012 4.75 1.19 .40 2.98 .144 11. 36 79.0 34.3 g .0777 1,170 15,000
272______ ____ _____________ 4 .012 4.81 1.20 . 39 3.08 .140 9.52 68.0 27.1 g .0757 1,670 22, 000
275_____ __________ ________ 4 .012 4.84 1.21 .40 3.03 . 144 7.40 51. 0 20.0g .0762 2,025 26,600
276 __________ _________ ____ 4 .012 4.88 1.22 . 39 3.13 .140 7.32 52.0 19.9g . 0770 1, 850 24, 000
277__ ______ ___ _________ ___ 4 . 012 4.82 1.20 .40 3.00 .144 7.34 51.0 19.9 g . 0768 2,420 31,500
278__ ______ _______ ________ 4 .012 4.81 1.20 . 40 3.00 .144 5. 46 38.0 13. 4 g . 0767 1,650 29,000
279_______________________ 4 . 012 4. 86 l. 21 . 40 3. 03 . 144 5. 41 38. 0 13. 4 g . 0777 1, 720 29, 500
280 ______________________ 1 4 . 012 4.85 1.21 .39 3.10 . 140 5. 36 38.0 13.0g .0765 1,655 29,000
SUPPORTED EDGES
263 ... -------------------- 4 0. 012 4. 70 1.17 0. 39 3. 00 0.140 15. 26 109. 0 48. 6 g 0. 0776 l , 500 19, 300
264 __ _ -- - ----------------- 4 . 012 4. 73 l.18 . 39 3. 03 .140 15. 24 109.0 48. 3 g . 0770 I, 805 23, 500
265 __ _ --------- - ---------- 4 . 012 4. 75 1.19 . 38 3. 05 . 137 15. 22 111. 0 48. 0 g . 0764 I, 580 20, 600
28L. -------------------- 4 . 012 4. 77 1. 19 . 39 3. 05 .140 13. 28 95. 0 40. 7 g . 077C 1, 695 22,000
282 __ _ -------------------- 4 .012 4. 77 1.19 . 39 3. 05 . 140 13. 38 95. 0 40. 7 g . 0765 1, 565 20, 500
273.__ -- - ------------- ---- 4 . 012 4. 80 1. 20 . 40 3. 00 .144 9. 52 66. 0 27. 2 g . 0760 I, 880 24, 700
274 __ _ -- - ----------------- 4 . 012 4.82 I. 20 . 40 3. 00 .144 9. 46 66. 0 26. 9 g . 0757 I, 885 24, 900
' L is tbe distance between knife edges. The actual length at tbe specimen was 1.60 inches less.
18
FlGURE 20.
19
) :s1ccn ·
FIGURE 21.
0
r