13. Study of the stress and strain state of the multilayer bellows

Annotation: Strength calculation example of the specific design bellows is taken to consider one of the possible approaches to the numerical simulation of the stress and strain state of the multilayer bellows. Proposed approach is based on the use of axial symmetry of the structure for transition from 3D calculation model to 2D one. Calculations take place in the elastoplastic setup, using the software package of the finite elements method. As an example of the proposed approach static and fatigue strength of the three-layer steel bellows of the Cyclone-4M fuel supply line are calculated. Calculation of the static strength of the bellows, loaded with internal pressure, showed that layer stresses achieve yield strength, at the same time preserving the bearing capacity of the structure. Results of the simulated change in the stress and strain state of the bellows per one cycle of the variable reloading were taken to find the amplitude of the plastic deformations in the most loaded area of the bellows, which allowed estimation of its fatigue strength in the conditions of lowcycle loading. Advantage of the proposed approach to the multilayer bellows strength evaluation is that it does not require large volumes of RAM and time to do the calculations.