<DOC>
<DOCNO>
822
</DOCNO>
<TITLE>
effects of imperfections on buckling of thin cylinders
and columns under axial compression .
</TITLE>
<AUTHOR>
donnell,l.h. and wan,c.c.
</AUTHOR>
<BIBLIO>
j. app. mech. 1950.
</BIBLIO>
<TEXT>
  von karman and tsien have shown that under elastic
conditions the resistance of perfect thin cylinders subjected
to axial compression drops precipitously after buckling
.  it is considered that this indicates that this type of
buckling is very sensitive to imperfections or disturbances .
in this paper the effects of certain imperfections of shape
turbances combined) are studied by the large-deflection
shell theory developed in a previous paper (2) .
  it is found that two types of buckling failure may occur .
one is of a purely elastic type which occurs when the peak
of the average stress versus average strain curve is reached,
while the other type is precipitated by yielding, which for
thicker cylinders or lower-yield material may occur before
such a peak is reached .  curves are derived giving the dependence
of each type of failure upon the dimensions and
elastic and yield properties of the specimen and also upon
an /unevenness factor/ u which determines the magnitude
of the initial imperfections and is assumed to depend
on the method of fabrication .  the relations derived are in
line with test results, and similar studies of the buckling
of struts indicate that the magnitude of the initial imperfections
which have to be assumed to explain test strengths
are reasonable .
</TEXT>
</DOC>
