Study of the analytical solutions and modelling of nonlinear buckling in bellows

Belows are one of widely used elements in various industries. These elements often contain an internal fluid flow and they are used as length compensator, vibration absorber and sealer. Usually they are under pressure and out of range increasing in pressure can cause buckling of bellows. There are two types of buckling in bellows known as column buckling and in-plain buckling. In this paper first, a comprehensive study was done on analytical solutions of bellows buckling in the literature and then both types of buckling were investigated by using FEM software ABAQUS and the results were compared with the experimental results that had been reported in references. According to the results, although elastic analysis of belows buckling gives correct mode shapes, the buckling pressure obtained by this method is several times as much the experimental one. Then, buckling pressure is computed by applying imperfection according to the primary buckling mode shapes and nonlinear analysis was done by the use of pressure-displacement curve. Finally, necessary number of buckling mode shapes applied as imperfection and the amount of the mode shape amplitude required were investigated by comparing the results with the experimental one, and good agreement between FEM and experimental results was obtained.