Answer:
An inflatable object usually consists of an air-filled foil bag with internal and external stiffening elements. The shape of the pressurized foil bag depends on:
Applied pressure or air volume introduced in the foil bag
Membrane stress distribution in the foil membrane
Local placement and design of the stiffening elements
Such a model can be modeled in RFEM using the RF‑FORM‑FINDING add-on module and simulated for certain load situations. To do this, proceed as follows:
- Open RFEM and activate the RF‑FORM‑FINDING add-on module.
- Define the material properties for the enclosing foil material and the enclosed air medium.
- Use membrane elements to model the foil bag geometry, including the stiffeners, by approximating the desired target geometry.
- Define the forming membrane stresses for the form-finding process on the membrane body.
- Define a gas volume with a description of the atmosphere in the foil bag.
- Define the internal pressure of the foil bag for the form-finding process using the gas pressure load in a load case with the "Form-Finding" category.
- Apply a realistic support of the foil bag body.
- Start the calculation of the RF‑FORM‑FINDING process to obtain the desired target geometry.
The load situation can then be simulated in a subsequent load case. To do this, proceed as follows:
- Define a load case and select the corresponding load case category.
- Describe the load to be analyzed using the available load catalog.
- Start the calculation of the load case to obtain the results based on the previously determined target geometry.
