<DOC>
<DOCNO>
1134
</DOCNO>
<TITLE>
torispherical shells - a caution to designers .
</TITLE>
<AUTHOR>
galletly,g.d.
</AUTHOR>
<BIBLIO>
j. eng. for industry, 1959, 51.
</BIBLIO>
<TEXT>
  it has recently become apparent, through
a rigorous stress analysis of a specific case
that designing torispherical shells by the
current edition of the asme code on unfired
pressure vessels can lead to failure during
proof-testing of the vessel .  the purpose
of the present paper is to show in what
respects the code fails to give accurate results .
as an illustrative example, a hypothetical
pressure vessel with a torispherical head
having a diameter-thickness ratio of 440 was
selected .  the supports of the vessel were
considered to be either on the main cylinder
or around the torus .  the vessel was subjected
to internal pressure and the elastic
stresses in it were determined rigorously and
by the code .  a comparison of the two
revealed that the code predicted stresses in the
head which were less than one half of those
actually occurring .  furthermore, the code
gave no indication of the presence of high
compressive circumferential direct stresses
which exceeded 30,000 psi for practically
the entire torus .  if the head had been fabricated
using a steel with a yield point of
would have failed or undergone large
deformations, whereas the code would have predicted
that it was safe .  the code's rules
for torispherical heads are thus in need of
revision for certain geometries .  the
implications of the foregoing results are currently
being studied by the asme,. in the interim,
however, designers should exercise care in
applying the code to torispherical shells .
  it is also shown in the paper that the use
of the membrane state as a particular solution
of the differential equations is not a
good approximation for toroidal shells of the
type considered .
</TEXT>
</DOC>
