Membrane Structures with Wind Loads from CFD Wind Simulation
2020-03-24
3:00 PM - 4:15 PM CET
Free
Webinar | Membrane Structures with Wind Loads From CFD Wind Simulation
This webinar demonstrates how wind loads can be determined in RFEM for membrane structures by means of CFD wind simulations.
Time Schedule
00:00
Introduction
04:00
Modeling of a grandstand roof including loading (dead load, snow)
46:40
Wind load generation based on CFD
55:00
Combination of loadings
1:03:20
Stability analysis in RF-STABILITY
1:07:20
Designing members in RF-STEEL EC3
1:10:10
Consideration of additional objects influencing the wind flow
Presentation Model to Download
Below, under Models to Download, you will find the model(s) used in the webinar. This will allow you to independently follow the webinar step by step with the provided model after the presentation is complete.
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.
The form-finding process in RF-FORM-FINDING displaces the corner nodes of FE elements of a membrane surface in space until the defined surface stress is in equilibrium with the boundary conditions. This displacement is independent of the element geometry. In the case of elements with four corner nodes, the free displacement may cause spatial drilling in the element plane and thus exceed the validity limits of the calculation; therefore, triangular elements are generally recommended for form‑finding systems. Triangular elements remain independent of the corner node displacement and stay within the calculation limitations.
The form-finding process in RFEM seeks an equilibrium state where the defined prestress of membranes and the prestress or length changes of cable elements with boundary reactions are in equilibrium. For this, the program provides the option to define an isotropic or an orthotropic prestress state for membranes.
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.
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.
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.
The Form-Finding add-on finds the optimal shape of members subjected to axial forces and tension-loaded surface models. The shape is determined by the equilibrium between the member axial force or the membrane stress and the existing boundary conditions.
Structural engineering software for a finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids, and contact elements
The Nonlinear Material Behavior add-on allows you to consider material nonlinearities in RFEM for example, isotropic plastic, orthotropic plastic, isotropic damage).
The Construction Stages Analysis (CSA) add-on allows for considering the construction process of structures (member, surface, and solid structures) in RFEM.
The modern 3D structural analysis and design program is suitable for the structural and dynamic analysis of beam structures as well as the design of concrete, steel, timber, and other materials.
The Structure Stability add-on performs the stability analysis of structures. It determines critical load factors and the corresponding stability modes.
RWIND 2 is a program (digital wind tunnel) for the numerical simulation of wind flows around any building geometries with determination of the wind loads on their surfaces. It can be used as a stand-alone application or used together with RFEM and RSTAB for complete structural analysis and design.
The Concrete Design add-on allows for various design checks according to international standards. You can design members, surfaces, and columns, as well as perform punching and deformation analyses.
The Timber Design add-on performs the ultimate, serviceability, and fire resistance limit state design checks of timber members according to various standards.
The Masonry Design add-on for RFEM allows you to design masonry using the finite element method. It was developed as part of the research project titled DDMaS – Digitizing the Design of Masonry Structures. The material model represents the nonlinear behavior of the brick-mortar combination in the form of macro-modeling.
The Steel Joints add-on for RFEM allows you to analyze steel connections using an FE model. The FE model is generated automatically in the background and can be controlled via the simple and familiar input of components.
The Timber Design add-on performs the ultimate, serviceability, and fire resistance limit state design checks of timber members according to various standards.