Buckling of rubber bellows under vacuum

JRP

Is it possible to make a buckling analysis in Mecway of rubber bellows which has a vacuum inside? I assume this is the Buckling 3D analysis type. Please check attached screenshots.

Victor

Yes

The Buckling 3D analysis type is only a linear analysis and can give an idea of the mode shapes but for something with large prebuckling deformation like I expect this would have, it might not be accurate enough.

As safer way is to use the Nonlinear Static 3D analysis type with the CCX solver, some time steps, Automatic time stepping turned on and with the pressure load ramped up from zero. This models the progression of deformation leading up to buckling, allows you to define a hyperelastic material instead of just linearly elastic which would be important if strains are large, and can include contact. You'll also need to include some asymmetry in the geometry or load to initiate buckling.

JRP

Thanks Victor,

I will check it out and maybe post some questions later if this project comes to realization.

Sergio

Have made some analysis (and real vacumm tests at low and high temperature) of this kind of part in the past, for pickup engine air intakes. We use EPDM rubber and other solver in that moment. As Victor says, you need to perform an no lineal static analysis with hyperelastic material.