Abstract
In this paper, we investigate the effect of torsion on the initiation of localized bulging in an inflated cylindrical tube that is made of an incompressible material. When the twisting moment
M
is fixed, the bifurcation condition for localized bulging is derived in a simple form. Moreover, it is shown that the value of pressure associated with the onset of the bulge increases as the twisting moment increases. Therefore, localized bulging may be delayed or prevented when a torsion is applied to the tube. Our results indicate that the torsion reduces the radial and axial expansions of the tube during the inflation. The effect of the tube thickness on the onset of localized bulging is examined, and we find that the torsion plays a very important role in thin tubes.