Back to Features
Is this page helpful?
2199x
001402
2019-10-24

Display of Topology on Deformed Structure

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.

Activated Display Option: Topology on Form-Finding Form
Activated Display Option: Topology on Form-Finding Form
  • Mia: AI Assistant
  • Latest Features
Events
Videos
Models to Download
Knowledge Base Articles
KB 001895 | Origin of Formula for Stability Failure of Individual Members Subjected to Compression
Every day, thousands of structural engineers design structural components using design check formulas that include the critical buckling load. But where do these old formulas come from, that Leonard Euler established over 200 years ago and that form the basis of all three structural steel design concepts?
Basic Shapes of Membrane Structures [1]
This paper is focused on the specific aspects of designing membrane structures that have specific requirements, such as form-finding and cutting pattern generation. An integral part of the design of these structures is the process of finding suitable prestressed shapes and generating cutting patterns. The text briefly describes two basic processes in the design of membrane structures. The physical principles are explained and the individual theses illustrated by examples.
Windbreak Porous Fabric Structure in RFEM & RWIND
Windbreak structures are special types of fabric structures which protect the environment from harmful chemical particles, abate wind erosion, and help to maintain valuable sources. RFEM and RWIND are used for wind-structure analysis as one-way fluid-structure interaction (FSI). This article demonstrates how to structural design windbreak structures using RFEM and RWIND.
RWIND 2 is a program for generating wind loads based on CFD (Computational Fluid Dynamics). The wind flow numerical simulation is generated around any building, including irregular or unique geometry types, to determine the wind loads on surfaces and members. RWIND 2 can be integrated with RFEM/RSTAB for the structural analysis and design or as a stand-alone application.
Screenshots
Product Features
Considering Initial State

Compared to the RF-FORM-FINDING add-on module (RFEM 5), the following new features have been added to the Form-Finding add-on for RFEM 6:

  • Specification of all form-finding load boundary conditions in one load case
  • Storage of form-finding results as initial state for further model analysis
  • Automatic assignment of the form-finding initial state via combination wizards to all load situations of a design situation
  • Additional form-finding geometry boundary conditions for members (unstressed length, maximum vertical sag, low-point vertical sag)
  • Additional form-finding load boundary conditions for members (maximum force in member, minimum force in member, horizontal tension component, tension at i-end, tension at j-end, minimum tension at i-end, minimum tension at j-end)
  • Material types "Fabric" and "Foil" in material library
  • Parallel form-findings in one model
  • Simulation of sequentially building form-finding states in connection with the Construction Stages Analysis (CSA) add-on
Surface Load

Once you activate the Form-Finding add-on in the Base Data, a form-finding effect is assigned to the load cases with the load case category "Prestress" in conjunction with the form-finding loads from the member, surface, and solid load catalog. This is a prestress load case. It thus mutates into a form-finding analysis for the entire model with all member, surface, and solid elements defined in it. You reach the form-finding of the relevant member and membrane elements amid the overall model by using special form-finding loads and regular load definitions. These form-finding loads describe the expected state of deformation or force after the form-finding in the elements. The regular loads describe the external loading of the entire system.

Considering Initial State

Do you know exactly how the form-finding is performed? First, the form-finding process of the load cases with the load case category "Prestress" shifts the initial mesh geometry to an optimally balanced position by means of iterative calculation loops. For this task, the program uses the Updated Reference Strategy (URS) method by Prof. Bletzinger and Prof. Ramm. This technology is characterized by equilibrium shapes that, after the calculation, comply almost exactly with the initially specified form-finding boundary conditions (sag, force, and prestress).

In addition to the pure description of the expected forces or sags on the elements to be formed, the integral approach of the URS also enables a consideration of regular forces. In the overall process, this allows, for example, for a description of the self-weight or a pneumatic pressure by means of corresponding element loads.

All these options give the calculation kernel the potential to calculate anticlastic and synclastic forms that are in an equilibrium of forces for planar or rotationally symmetric geometries. In order to be able to realistically implement both types individually or together in one environment, the calculation provide you with two ways to describe the form-finding force vectors:

  • Tension method - description of the form-finding force vectors in space for planar geometries
  • Projection method - description of the form-finding force vectors on a projection plane with fixation of the horizontal position for conical geometries
Results

The form-finding process gives you a structural model with active forces in the "prestress load case" This load case shows the displacement from the initial input position to the form-found geometry in the deformation results. In the force or stress-based results (member and surface internal forces, solid stresses, gas pressures, and so on), it clarifies the state for maintaining the found form. For the analysis of the shape geometry, the program offers you a two-dimensional contour line plot with the output of the absolute height and an inclination plot for the visualization of the slope situation.

Now, a further calculation and structural analysis of the entire model is performed. For this purpose, the program transfers the form-found geometry including the element-wise strains into a universally applicable initial state. You can now use it in the load cases and load combinations.

Frequently Asked Questions (FAQ)
How can I export the deformed mesh shape to a .dxf file in RFEM 6 for my fabric membrane structure?
How do I correctly model the load flow when a beam acts as a support?
I would like to analyze temporary structures. Which programs do you recommend?
Which Dlubal programs do I need for tensile membrane structures?
I would like to analyze cable and tensile structures. Is it possible to use RFEM or RSTAB for this?

How do I create a user-defined fabric?
Customer Projects
Recommended Products for You
Display Product Family