<DOC>
<DOCNO>
723
</DOCNO>
<TITLE>
on the fatigue failure of structures due to vibrations excited
by random pressure fields .
</TITLE>
<AUTHOR>
alan powell
</AUTHOR>
<BIBLIO>
the university, southampton
</BIBLIO>
<TEXT>
on the assumption that the forced modes of vibration of a structure,
subjected to pressure fluctuations random in time and space, can be
approximated by the composition of the motions of the uncoupled
natural modes, a general analysis is made using the ideas of vibration
theory and spectrum analysis .  the power spectrum, and hence the
rms value, of any quantity depending linearly upon structural
distortions is derived and it involves a quantity (called the /joint
acceptance/) concerning the spacewise structure of the pressure
field and of the geometry of the modes of vibration .  it is shown how
this result may be used (on assuming /normal/ randomness) to estimate
the fatigue life on the hypothesis of cumulative damage .
</TEXT>
</DOC>
