Gasket deformation during bolt up
In order to understand the bolt relaxation and bolt
scatter behaviour during each pass, gasket condition
is monitored at the end of each pass. Plots of displacements
UX, UY, and UZ at the last pass are shown in
Fig. 11(a). From axial displacement (UY) plot it is
observed that the gasket shape is changed and the
gasket no longer retained its original shape. Gasket
deformation is remarkable after the last pass as its
surface being in contact with the flange is observed
sheared resulting in its permanent deformation. Variation
of axial displacement along gasket circumference
with maximum at locations closer to bolt 2 and
3 and minimum at 1808 location is observed. For the
last pass, maximum axial displacement observed is
0.236 mm (near bolt 3) and minimum 0.023 mm
(near bolt 6). This concludes that the gasket undergoes
uneven compression circumferentially.