Rubber Bellows act as extension joints of rotating gears like pump, pipe works and chillers. They are highly flexible and therefore can be fit easily to even some misaligned locations allowing lateral, axial and angular movements. They are also used to isolate noise and vibration to some optimum level. They have there extensive use in fluid filling systems, water treatment plants, hydraulic ram protections etc. Some of the advantages includes flexibility, resistance to corrosion, lightweight, decreasing vibrations etc. In this project, stress analysis of a rubber below was performed. Three types of test load cases were performed; tension, torsion and bending.
Geometry and Mesh
The geometry used was created on Onshape and than imported directly to SimScale platform via import operation. The geometry is shown in the figure below.
To create mesh for the analysis, second order Parametrized tetrahedralization was used with minimum and maximum edge length of 3e-4 and 4e-3 respectively. Mesh is shown in the figure below.
Static analysis - advanced with Nonlinear analysis set as true was selected for the analysis. Bellow was given a hyperelastic rubber material using Mooney-Rivlin model. The bottom face of the bellow was fully constrained whereas the red highlighted faces were used for the load applications. Total of two types of fixed value and four types of Rotating motion boundary conditions were used to perform the desired load cases. Moreover, these multiple boundary conditions on different time steps were applied in a single simulation with the help of functions. Simulation was run using MUMPS as Equation solver on 8 core machine considering only 2 cores for the computation for total time of 6 seconds. Furthermore, reaction forces on the fixation and stress and strain in whole bellow were requested under Result Control. The simulation took 95 min. to complete.
The figures below shows the stresses formed in rubber bellow for tension, torsion, initial bending and final bending respectively.
The figure below shows the final deformed shape of the bellow compared to the initial state.
Furthermore, the figure below shows the cauchy stresses plot in bellow.
Finally, figures below show animation of the bellow considering stress contour plot and displacement contour plot with displacement vectors respectively.