A spherical balloon membrane is filled with gas with atmospheric pressure and defined volume (these values are used for FE model definition only). Determine the overpressure inside the balloon due to the given isotropic membrane prestress. The add-on module RF-FORM-FINDING is used for this purpose. Elastic deformations are neglected both in RF-FORM-FINDING and in the analytical solution; self-weight is also neglected in this example.
Balloon – Prestressed Membrane
With the activated option 'Topology on Form-Finding Form' in Project Navigator - Display, the model display is optimized based on the form-finding geometry. For example, the loads are displayed in relation to the deformed system.
Activating 'Show Form-Finding' in the shortcut menu leads to an automatic preliminary form-finding according to the saved form-finding properties when you change the structure of membrane surfaces. This interactive graphics mode is based on the force density method.
More Information FAQIn RFEM, there is an option to couple surfaces with the stiffness types "Membrane" and "Membrane Orthotropic" with the material models "Isotropic Nonlinear Elastic 2D/3D" and "Isotropic Plastic 2D/3D" (add-on module RF-MAT NL erforderlich).
This functionality enables simulation of the nonlinear strain behavior of ETFE foils, for example.
The results of solid stresses can be displayed as colored 3D points in the finite elements.