Structural engineering FEA software RFEM is the basis of a modular software system. RFEM is used to define structures, materials, and loads for planar and spatial structural systems consisting of plates, walls, shells and members. The program also allows you to create combined structures as well as model solid and contact elements.
RF‑FORM‑FINDING searches for shapes of structures subjected to tension or compression, such as membrane and cable structures. The shape is calculated by the equilibrium between the surface stress (specified prestress and additional load such as self‑weight, pressure, etc.) and the given boundary requirements. The prestressed model is afterwards used as the initial state for all subsequent calculations.
RF‑CUTTING‑PATTERN generates and organizes cutting patterns for membrane structures. Boundary conditions of the cutting patterns on curved geometry are determined by boundary lines and independent planar cutting lines or geodesic cutting lines. The flattening process is performed according to the minimum energy theory.
The RF-MAT NL add-on module allows for consideration of nonlinear material behavior in RFEM.
It offers the 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" (RF-MAT-NL add-on module required). This functionality enables the simulation of the nonlinear strain behavior of, for example, ETFE foils.
For structural analysis and design of tensile membrane structures or their substructures, find more useful add‑on modules under the Steel Structures as well as Aluminum and Light-Weight Structures industry.
A unique roof structure was built for the main bus station in Aarau, Switzerland in 2013.
The canopy has a cloud-like shape and contains the largest single‑chamber cushion in the world. The ETFE cushion has a volume of 63,919.55 ft³ and covers an area of 11,517.38 ft².
Allianz Arena is a soccer stadium in Munich, Germany, which hosted the opening match of the 2006 FIFA World Cup.
The translucent exterior facade of the stadium emits light in various colors and thus makes the whole arena building very special.
The Eden Project is a complex of two biomes and outdoor gardens with plants from many diverse climates and environments.
The biome is a steel frame structure with cladding panels consisting of triple-layered membrane cushions made of ETFE foil.
A giant wooden airship “suspended” above the Centre for Contemporary Art in Prague, Czech Republic, has been opened to the public in December 2016.
The unique timber and steel airship structure “Gulliver” will serve as a space for literature.
![Figure 01 - Basic Shapes of Membrane Structures [4]](/-/media/Images/website/pages/support-and-learning/support/knowledge-base/001437/01-en-png.png)
This paper is focused on the specific aspects of designing membrane structures. These structures have specific requirements such as form‑finding and cutting patterns generation. These topics are the focus of many research works and there are many methods proposed to achieve the desired results. However, in this paper these issues will be discussed more from the practical point of view than from the theoretical one. The paper will be followed by examples, which will complement the discussed topic and show the special attention required during the design process.
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 a geometric position in which 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.
Product Video: Add-on Modules RF-FORM-FINDING & RF-CUTTING-PATTERN
Dlubal Webinar: Form-Finding and Cutting Patterns of Membrane Structures in RFEM
Webinar: Tensile Membrane Structure Design in RFEM
Dlubal Software is a member of the TensiNet Association.
RFEM offers the 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" (RF-MAT NL add-on module required).
This functionality enables the simulation of the nonlinear strain behaviour of, for example, ETFE foils.
Main Program
Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements
Add-on Module
Form-finding of tensile membrane and cable structures
Add-on Module
Generation of cutting patterns for tensile membrane structures
Add-on Module
Design of steel members according to Eurocode 3
Module Extension for RF-STEEL EC3 and RF-STEEL AISC
Warping torsion analysis according to the second-order theory with 7 degrees of freedom
Module Extension for RF-STEEL EC3
Plastic design of cross-sections according the Partial Internal Forces Method (PIFM) and Simplex Method
Add-on Module
Design of aluminum members according to Eurocode 9
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