<DOC>
<DOCNO>
824
</DOCNO>
<TITLE>
on the concept of stability of inelastic systems .
</TITLE>
<AUTHOR>
drucker,d.c. and onat,e.t.
</AUTHOR>
<BIBLIO>
j.ae.scs., 21, 1954, 543.
</BIBLIO>
<TEXT>
  simple models are employed to bring out the large and important
differences between buckling in the plastic range and
classical elastic instability .  static and kinetic criteria are compared
and their interrelation discussed .  nonlinear behavior in
particular is often found to be the key to the physically valid
solution .  the nonconservative nature of plastic deformation in
itself or in combination with the nonlinearity requires concepts
not found in classical approaches .  conversely, the classical
linearized condition of neutral equilibrium is really not relevant
in inelastic buckling .  plastic buckling loads are not uniquely
defined but cover a range of values and are often more properly
thought of as maximum loads for some reasonable initial imperfection
in geometry or dynamic disturbance .
  the models indicate that basically the same information is
obtained from essentially static systems by assuming initial imperfection
in geometric forms as by assuming dynamic disturbances
.  one approach complements the other and both are helpful
in obtaining an understanding of the physical phenomena .
</TEXT>
</DOC>
