• Version
• 218 Downloads
• 1.75 MB File Size
• 1 File Count
• April 23, 2016 Create Date
• April 23, 2016 Last Updated

National Advisory Committee for Aeronautics, Technical Notes - Strength Tests of Thin Walled Duralumin Cylinders in Combined Transverse Shear and Bending

This report is the fourth of a series presenting the
results of strength tests on thin—walled cylinders and
truncated cones of circular and elliptic section; it in—
cludes the results obtained from combined shear and bend—
ing tests on 100 thin—walled duralumin cylinders of circu~
1ar section with ends clamped t5"figid bulkheads. The
tests show that as the ratio of moment to shear varies
from small to large values the failure changes from a
shear to a bending type. In the report a chart is pre—
sented that shows the corresponding changes in strength.
As part of an investigation of the strength of
stressed—skin structures for aircraft, the National Advi-
sory Committee for Aeronautics in cooperation with the
Army Air Corps; the Bureau of Aeronautics, Navy Depart-
ment; the National Bureau of Standards; and the Bureau of
Air Commerce has made an extensive series of tests on
thin—walled duralumin cylinders and truncated cones of
circular and elliptic section. In these tests the abso-
lute and relative dimensions of the specimens were varied
to study the types of failure and to establish useful
quantitative data in the following loading conditions:
torsion, compression, bending, and combined loading.
The first three reports of this series (references 1,
2, and 3) present the results obtained in the torsion, the
compression. and the purenbending tests of cylinders of
circular section. This report presents the results ob—
tained in tests of cylinders of circular section in com?
bined transverse shear and bending.
The duralumin (Al. 00. of Am. 175T) used in these
tests was obtained from the manure-cturer in sheet form
with nominal thicknesses of 0. 011, 0.016, and 0.022 inch.
The properties of this material as determined by the
National Bureau of Standards from specimens selected at
random are given in references-1 and 2. Since all the
test cylinders failed by elastic buckling of the walls at
stresses considerably below the yield—point stress, the
modulus of elasticity E, which- was substantially con~
stant for all sheet thicknesses, is the only important
property of the material that need be considered. For
all cylinders an average value of E (10.4 X 1-0G pounds
per square inch) was used in the analysis of the results.