also observed that due to the elongation, outer
sealing ring has changed more or less to octagonal
shape.
Figure 11(b) shows the radial displacement (UX) of
the gasket with respect to flange at the end of last
pass. The maximum radial displacement noted is
almost 3 mm (at locations closer to bolt 1 and 5).
UX close to bolt 1 is 3 mm, while on the opposite
side (at 1808), it is 23 mm, which shows that during
bolt up, gasket stretches and shears in the radial
direction. Figure 11(c) represents the circumferential
(hoop) displacement (UZ) of the gasket at the end of
last pass. Maximum UZ of almost 3.5 mm (close to
bolt 3), shows that gasket during bolt up undergoes
rotation with respect to the flange, thus disturbing
the initial alignment with the flange and might possibly
lead to leakage. Figure 12(a) shows the maximum
values of UX, UY, and UZ for all the five passes.
FEA results are compared with the detailed experimental
results by Abid [2], who has used four different
gaskets of the samematerial and dimensions used
in FEA. He has reported the bending of the centring
ring during joint assembly of one of the gaskets.
The spiral wound portion was reasonably compressed,
and along one location it was found more
compressed. The same gasket was used for the
second time to make the other joint. After making
the joint, it was disassembled and the gasket was
taken out to see its condition this time. This time it
was found to be more compressed less than the centring
ring thickness on one side, i.e. some dents were
found along about 908 on one side and centring ring
was found more bent. A new gasket was used for
the third time to make the joint. After bolting up its
centring ring was not found bent. The gasket was
taken out after dismantling the joint to note its physical
condition. Its spirals were found damaged from
one side along with a dent at about 1808. Then
another gasket was used for other series of tests.
After performing the experiments for different loading,
gasket was found reasonably compressed with