Modelling Bellows Expansion Joints by Standard Beam Finite Elements

A procedure for modelling bellows expansion joints by the standard beam finite elements of I-DEAS Master Series 6 is presented. It is shown that the bellows dynamic behaviour can be modelled by beam elements by manipulating certain element parameters. The method will work in any software in which these parameters can be set by the user. Compared to a shell elements model the model size is reduced by at least a factor of 100. This is especially advantageous when the bellows is only a part of a system to be optimised with respect to overall design parameters. In comparison to existing "semi-analytical" methods the beam finite elements have the advantages of considering axial, bending and torsion degrees of freedom simultaneously and that the interaction between the bellows and the rest of the system, also modelled by beam or shell finite elements, is easily facilitated. The procedure is verified by experimental results from other investigators.