A simplified analysis method for buckling of bellows under internal pressure and its validation tests

摘要

In this paper a consistent simplified analysis method for the buckling of bellows under internal pressure is developed and its validation is shown by a series of buckling tests. The simplified analysis method is developed for three types ofbuckling; 1) the column squirm in elastic region, which occurs in case of a relatively large number of convolutions, 2) the in-plane squirm (root bulge), which occurs in case of a small number of convolutions, and 3) the column squirm in elastic-plasticregion. For the first two types of buckling, the simplified formulae which have already been seen in the literature are used. For the third, a simplified analysis procedure is newly proposed. The combination of the elastic column buckling theory and the fundamental axisymmetric elastic-plastic analysis of half convolution makes it possible to obtain nonaxisymmetric buckling pressure in the elastic-plastic region.Internal pressure buckling tests using various bellows specimens were conducted From these test results it is shown that the simplified analysis method predicts the critical pressure of bellows reasonably. The effects of initial bending deformation werealso investigated and it is found that they reduce the critical pressure only in the case of column squirm.