Added Fluid Mass for Bellows Expansion Joints in Axial Vibrations

Abstract

This paper presents the results of investigation of the fluid added mass in axial vibrations of bellows expansion joints. The added mass is shown to consist of three parts, one due to convolution translation in axial direction, another due to distortion of the convolution during vibration, and the third one due to the return flow in central section of bellows. The latter component was ignored due to its negligibility in comparison with the first two parts. The distortion component for a half-convolution has been determined using finite element analysis and the results are presented in graphical form for a typical range of bellows geometry. The total added mass is given in a form suitable for hand calculations.