Influence Of The Sidewall Off-Set Angle On The Rigidity And Stability Of Bellow

With the rapid development of the expansion joint industry, a large number of studies on the expansion joint in the aspects of fatigue life calculation, creep analysis and buckling check were performed by means of the computer numerical simulation, and the results were used for updating the expansion joint design code. Many expansion joint design standards in the world were originally based on the EJMA code, but the subsequent development combined with different design experience and research results of specific countries. Obviously, the difference of these standards troubles the designers in the design of the expansion.Firstly, several standards for the design of expansion joint were compared in teams of application scope, stress evaluation, buckling check and fatigue calculation in this paper. It is found that EN13445 and ASME provide the most detailed structures and dimensions requirement for U-shaped bellows, which contained restriction of the arc radius, the off-set angle of the sidewall, the number of plies and the convolution height. Especially, the restriction of the off-set angle of the sidewall was never mentioned by other design standards. Secondly, the influence of the sidewall off-set angle on capacities of U-shaped bellows was numerically studied in terms of strength, rigidity and stability. It is valuable for optimizing the expansion joint structure and revising the expansion joint design standards.Finally, based on the calculated results, a software for the axial rigidity calculation of the U-shaped bellows was developed to facilitate engineering design of bellows. The software was programmed by working the visual basic programming language VB on the internationally used finite element program ANSYS. It is helpful for engineers to numerically design the U-shaped bellows without getting deep into the details of the finite element method.