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 FAQAutomatic Preliminary Form-Finding of Membrane Surfaces
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RFEM and RSTAB are able to cover a large number of branches in the building and construction industry with their generally usable structural frame analysis and FEM programs. Designing cable structures is thus also possible in both software solutions. Some assistance tools for modeling and design will be presented in the following text.
Cable and tensile membrane structures are regarded as very slender and aesthetic building structures. The partly very complex double-curved shapes can be found using suitable form-finding algorithms. One possible solution is to search for the form via the equilibrium between the surface stress (provided prestress and an additional load such as self-weight, pressure, and so on) and the given boundary conditions.
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The RF-FORM-FINDING add-on module determines equilibrium shapes of membrane and cable elements in RFEM. In this calculation process, the program searches for such geometric position where the surface stress/prestress of membranes and cables is in equilibrium with natural and geometric boundary conditions. This process is called form-finding (hereinafter referred to as FF). The FF calculation can be activated in RFEM globally in the "General Data" of a model, "Options" tab. After selecting the corresponding option, a new load case or a calculation process called RF-FORM-FINDING is created in RFEM. An additional FF parameter is available for defining surface stress and prestress when entering cables and membranes. By activating the FF option, the program always starts the form-finding process before the pure structural calculation of internal forces, deformation, eigenvalues, etc., and generates a corresponding prestressed model for further analysis.
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 FAQ
In 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 is required).
This functionality enables simulation of the nonlinear strain behavior of ETFE foils, for example.
Use the "Independent mesh preferred" option in the FE mesh settings to create an independent FE mesh for the integrated objects. This allows you to generate a significantly more detailed and precise FE mesh for individual objects that are integrated into one another.
Although I modeled two identical systems, I got a different shape. Why?
How is it possible to make factorized combinations of a dead load in the context of form‑finding?
It seems that the members stay not deformed after my RF‑FORM‑FINDING calculation. What did I wrong?
How do I model a suspended membrane roof structure with line supports?
How do I model a tent roof with two cone tips?
How is an inflatable object simulated in RFEM?
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