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.
You can display the RWIND results directly in the main program. In the Navigator - Results, select the Wind Simulation Analysis result type from the list above.
Currently, the following results are available, which refer to the RWIND computational mesh:
- Surface pressure
- Surface cp coefficient
- Wall distance y+ (steady flow)
For the meshing of solids, you have the option of arranging a layered FE mesh. This option allows you to perform a defined division of the solid with finite elements between two parallel surfaces.
Go to Explanatory VideoUse RWIND 2 Pro to easily apply a permeability to a surface. All you need is the definition of
- the Darcy coefficient D,
- the inertial coefficient I, and
- the length of the porous medium in the direction of flow L,
to define a pressure boundary condition between the front and back of a porous zone. Due to this setting, you obtain the flow through this zone with a two-part result display on both sides of the zone area.
But that's not all. Furthermore, the generation of a simplified model recognizes permeable zones and takes into account the corresponding openings in the model coating. Can you waive an elaborate geometric modeling of the porous element? Understandable – we have good news for you then! With a pure definition of the permeability parameters, you can avoid complex geometric modeling of the porous element. Use this feature to simulate permeable scaffolding, dust curtains, mesh structures, and so on.
More InformationDo you already know the editor for mesh refinement control? It is a great help for your work! Why? It's easy – it gives you the following options:
- Graphic visualization of the areas with mesh refinements
- Mesh refinement of zones
- Deactivating the standard 3D solid mesh refinement with transversion into the corresponding manual 3D mesh refinements.
These options help you to formulate a suitable rule for meshing the entire model, even for the models with unusual dimensions. Use the editor to efficiently define small model details on large buildings or detailed meshing areas in the coating area of the model. You will be amazed!
The soil solids that you want to analyze are summarized in soil massifs.
Use the soil samples as a basis for a definition of the respective soil massif. This way, the program allows for user-friendly generation of the massif, including the automatic determination of the layer interfaces from the sample data, as well as the groundwater level and the boundary surface supports.
Soil massifs provide you with the option to specify a target FE mesh size independently of the global setting for the rest of the structure. You can thus consider the various requirements of the building and soil in the entire model.
Have you already discovered the tabular and graphical output of masses in mesh points? That's right, this is also part of the modal analysis results in RFEM 6. This way, you can check the imported masses that depend on various settings of the modal analysis. They can be displayed in the Masses in Mesh Points tab of the Results table. The table provides you with an overview of the following results: Mass - Translational Direction (mX, mY, mZ), Mass - Rotational Direction (mφX, mφY, mφZ), and the Sum of Masses. Would it be best for you to have a graphical evaluation as quickly as possible? Then you can also graphically display the masses in mesh points.
The object types listed below can be graphically assigned to the elements of the structure modeled in the program.
- Nodal supports
- Member shear panels
- Local reductions of member cross-sections
- Member transverse stiffeners
- Member longitudinal welds
- Effective lengths
- Boundary conditions
- Line supports
- Loads
- Member support
- Punching reinforcements
- Mesh refinements
- Surface reinforcements
- Surface results adjustments
- Surface support
- Service classes
- Imperfections
In addition to the "Mesh Refinement" and "Specific Direction" options for solids, you can also activate the "Grid for Results" option, which allows for organizing grid points in the solid space. Among other things, the center of gravity can be set as the origin. There is also the option to activate or deactivate the visibility of the grid for numerical results in "Navigator – Display" under Basic Objects.
- Calculation of stationary incompressible turbulent wind flow using the SimpleFOAM solver from the OpenFOAM® software package
- Numerical scheme according to the first and second order
- Turbulence models RAS k-ω and RAS k-ε
- Consideration of surface roughness depending on model zones
- Model design via VTP, STL, OBJ, and IFC files
- Operation via bidirectional interface of RFEM or RSTAB for importing model geometries with standard-based wind loads and exporting wind load cases with probe-based printout report tables
- Intuitive model changes via drag & drop and graphical adjustment assistance
- Generation of a shrink-wrap mesh envelope around the model geometry
- Consideration of environmental objects (buildings, terrain, and so on)
- Height-dependent description of the wind load (wind speed and turbulence intensity)
- Automatic meshing depending on a selected depth of detail
- Consideration of layer meshes near the model surfaces
- Parallelized calculation with optimal utilization of all processor cores of a computer
- Graphical output of the surface results on the model surfaces (surface pressure, Cp coefficients)
- Graphical output of the flow field and vector results (pressure field, velocity field, turbulence – k-ω field, and turbulence – k-ε field, velocity vectors) on Clipper/Slicer planes
- Display of 3D wind flow via animated streamline graphics
- Definition of point and line probes
- Multilingual user interface (German, English, Czech, Spanish, French, Italian, Polish, Portuguese, Russian, and Chinese)
- Calculations of several models in one batch process
- Generator for creating rotated models to simulate different wind directions
- Optional interruption and continuation of the calculation
- Individual color panel per result graphic
- Display of diagrams with separate output of results on both sides of a surface
- Output of the dimensionless wall distance y+ in the mesh inspector details for the simplified model mesh
- Determination of the shear stress on the model surface from the flow around the model
- Calculation with an alternative convergence criterion (you can select between the residual types pressure or flow resistance in the simulation parameters)
RWIND Basic uses a numerical CFD model (Computational Fluid Dynamics) to simulate wind flows around your objects using a digital wind tunnel. The simulation process determines specific wind loads acting on your model surfaces from the flow result around the model.
A 3D volume mesh is responsible for the simulation itself. For this, RWIND Basic performs an automatic meshing on the basis of freely definable control parameters. For the calculation of wind flows, RWIND Basic provides you with a stationary solve and RWIND Pro provides a transient solver for incompressible turbulent flows. Surface pressures resulting from the flow results are extrapolated onto the model for each time step.
When starting the analysis in the RFEM or RSTAB application, you trigger a batch process. It places all member, surface, and solid definitions of the model rotated with all relevant coefficients in the numerical wind tunnel of RWIND Basic. Furthermore, it starts the CFD analysis, and returns the resulting surface pressures for a selected time step as FE mesh nodal loads or member loads into the respective load cases of RFEM or RSTAB.
These load cases which contain RWIND Basic loads can then be calculated. Moreover, you can combine them with other loads in load and result combinations.
There's something new for you! To define odal mesh refinements, the options for FE length arrangement have been added:
- Radial
- Gradually
- Combined
Compared to the RF‑/DYNAM Pro - Natural Vibrations add-on module (RFEM 5 / RSTAB 8), the following new features have been added to the Modal Analysis add-on for RFEM 6 / RSTAB 9:
- Preset combination coefficients for various standards (EC 8, ASCE, and so on)
- Optional neglect of masses (for example, mass of foundations)
- Methods for determining the number of mode shapes (user-defined, automatic - to reach effective modal mass factors, automatic - to reach the maximum natural frequency)
- Output of modal masses, effective modal masses, modal mass factors, and participation factors
- Masses in mesh points displayed in tables and graphics
- Various scaling options for mode shapes in the Result navigator
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
Was your design successful? Then just sit back and relax. You benefit from the numerous functions in RFEM also here. The program gives you the maximum stresses of the masonry surfaces, whereby you can display the results in detail at each FE mesh point.
Moreover, you can insert sections in order to carry out a detailed evaluation of the individual areas. Use the display of the yield areas to estimate the cracks in the masonry.
- Automatic consideration of masses from self-weight
- Direct import of masses from load cases or load combinations
- Optional definition of additional masses (nodal, linear, or surface masses, as well as inertia masses) directly in the load cases
- Optional neglect of masses (for example, mass of foundations)
- Combination of masses in different load cases and load combinations
- Preset combination coefficients for various standards (EC 8, SIA 261, ASCE 7,...)
- Optional import of initial states (for example, to consider prestress and imperfection)
- Structure Modification
- Consideration of failed supports or members/surfaces/solids
- Definition of several modal analyses (for example, to analyze different masses or stiffness modifications)
- Selection of mass matrix type (diagonal matrix, consistent matrix, unit matrix), including user-defined specification of translational and rotational degrees of freedom
- Methods for determining the number of mode shapes (user-defined, automatic - to reach effective modal mass factors, automatic - to reach the maximum natural frequency - only available in RSTAB)
- Determination of mode shapes and masses in nodes or FE mesh points
- Results of eigenvalue, angular frequency, natural frequency, and period
- Output of modal masses, effective modal masses, modal mass factors, and participation factors
- Masses in mesh points displayed in tables and graphics
- Visualization and animation of mode shapes
- Various scaling options for mode shapes
- Documentation of numerical and graphical results in printout report
The number of degrees of freedom in a node is no longer a global calculation parameter in RFEM (6 degrees of freedom for each mesh node in 3D models, 7 degrees of freedom for the warping torsion analysis). Thus, each node is generally considered with a different number of degrees of freedom, which leads to a variable number of equations in the calculation.
This modification speeds up the calculation, especially for models where a significant reduction of the system could be achieved (for example, trusses and membrane structures).
The meshing algorithm of RWIND Simulation uses the boundary layer option to mesh the area near the model surface with a voluminous layer mesh. The number of layers is controlled by a user-defined parameter.
This fine mesh in the area of the model surface helps to represent the wind velocity close to the surface.
- 3D incompressible wind flow analysis with OpenFOAM® software package
- Direct model import from RFEM or RSTAB including neighboring and terrain models (3DS, IFC, STEP files)
- Model design via STL or VTP files independent of RFEM or RSTAB
- Simple model changes using Drag and Drop and graphical adjustment assistance
- Automatic corrections of the model topology with shrink wrap networks
- Option to add objects from the environment (buildings, terrain ...)
- Wind load determined over the height of the building, depending on standard-specific parameters (velocity, turbulence intensity)
- K-epsilon and K-omega turbulence models
- Automatic mesh generation adjusted to the selected depth of detail
- Parallel calculation with optimal utilization of the capacity of multicore computers
- Results in just minutes for low-resolution simulations (up to 1 million cells)
- Results within a few hours for simulations with medium/high resolution (1‑10 million cells)
- Graphical display of results on the Clipper/Slicer planes (scalar and vector fields)
- Graphical display of streamlines
- Streamline animation (optional video creation)
- Definition of point and line probes
- Display of aerodynamic pressure coefficients
- Graphical display of turbulence properties in the wind field
- Optional meshing using the boundary layer option for the area near the model surface
- Consideration of rough model surfaces possible
- Optional use of a seond-order numerical Order
- Multilingual user interface (for example, German, English, Spanish, French)
- Documentation possible in the RFEM and RSTAB printout report
Work on your models with efficient and precise calculations in the digital wind tunnel. RWIND 2 uses a numerical CFD model (Computational Fluid Dynamics) to simulate wind flows around objects. Specific wind loads are generated from the simulation process for RFEM or RSTAB.
RWIND 2 performs this simulation using a 3D volume mesh. The program provides automatic meshing; you can easily set the entire mesh density as well as the local mesh refinement on the model using a few parameters. A numerical solver for incompressible turbulent flows is used to calculate the wind flows and the surface pressures on the model. The results are then extrapolated to your model. RWIND 2 is designed to work with different numerical solvers.
We currently recommend using the OpenFOAM® software package, which has provided very good results in our tests and is also a frequently used tool for CFD simulations. Alternative numerical solvers are under development.
Surface reinforcements defined in the RF-CONCRETE Surfaces add-on module can be exported to Revit as reinforcement objects via the direct interface. To do this, you can optionally select surface, rectangular, polygon, and circular reinforcement areas in RF-CONCRETE Surfaces. In addition to bar reinforcement, it is possible to export mesh reinforcement.
With this function, it is possible to refine the FE mesh on surfaces automatically. The mesh refinement is gradual. In each step, the FE mesh is recreated based on an error comparison of the results in the previous calculation step. The numerical error is evaluated from the results of surface elements and is based on the energy formulation of Zienkiewicz-Zhu.
The error evaluation is carried out for a linear static analysis. We select a load case (or load combination) for which the FE mesh is generated. The FE mesh is then used for all calculations.
- Form-finding of:
- tension-loaded membrane and cable structures
- compression-loaded shell and beam structures
- mixed tension- and compression-loaded structures
- Consideration of gas chambers between surfaces
- Interaction with supporting structure (substructure design according to various standards)
- Surfaces as a 2D and members as a 1D element
- Definition of different prestress conditions for surfaces (membranes and shells)
- Definition of forces or geometrical requirements for members (cables and beams)
- Consideration of individual loads (self‑weight, inner pressure, and so on) in the form‑finding process
- Temporary support definitions for the form-finding process
- Automatic preliminary form-finding of membrane surfaces (more information...)
- Definition of isotropic or orthotropic material for structural analysis
- Optional definition of free polygon loads
- Transformation of form‑found shape elements into NURBS surface elements
- Possibility of combined form-finding by integration of preliminary form-finding
- Graphical evaluation of the new form using colored coordinates and inclination plots
- Complete documentation of the calculation including user-defined adaptive evaluation figures
- Optional export of the FE mesh as a DXF or Excel file
The nonlinear calculation adopts the real mesh geometry of planar, buckled, simple curved, or double curved surface components from the selected cutting pattern and flattens this surface component in compliance with the minimization of distortion energy, assuming defined material behavior.
In simplified terms, this method attempts to compress the mesh geometry in a press, assuming frictionless contact, and to find the state in which the stresses from flattening in the component are in equilibrium in the plane. This way, minimum energy and optimum accuracy of the cutting pattern are achieved. Compensation for warp and weft as well as compensation for boundary lines are considered. Then, the defined allowances on boundary lines are applied to the resulting planar surface geometry.
Features:
- Minimization of distortion energy in the flattening process for very accurate cutting patterns
- Application for almost all mesh arrangements
- Recognition of adjacent cutting pattern definitions to keep the same length
- Mesh application for main calculation
After the calculation, the "Point Coordinates" tab appears in the cutting pattern dialog box. In this tab, the result is displayed in the form of a table with coordinates and a surface in the graphical window. The coordinate table presents new flattened coordinates relative to the centroid of the cutting pattern for each mesh node. Furthermore, the cutting pattern with the coordinate system at the centroid is represented in the graphical window. When selecting a table cell, the respective node is displayed with an arrow in the graphic. In addition, the area of the cutting pattern is displayed below the node table.
Moreover, standard stress/strain results for each pattern are displayed in the RF‑CUTTING‑PATTERN load case in RFEM.
Features:
- Results in a table, including information about the cutting pattern
- Smart table relating to the graphic
- Results of flattened geometry in a DXF file
- Output of strains after flattening in order to evaluate the cutting patterns
- Results of strains after flattening for the evaluation of patterns
- Automatic consideration of masses from self-weight
- Direct import of masses from load cases or load combinations
- Optional definition of additional masses (nodal, linear, surface masses, as well as inertia masses)
- Combination of masses in different mass cases and mass combinations
- Preset combination coefficients according to EC 8
- Optional import of normal force distributions (in order to consider prestress, for example)
- Stiffness modification (for example, deactivated members or stiffnesses can be imported from RF-/CONCRETE)
- Consideration of failed supports or members
- Definition of several natural vibration cases (for example, to analyze different masses or stiffness modifications)
- Results of eigenvalue, angular frequency, natural frequency, and period
- Determination of mode shapes and masses in nodes or FE mesh points
- Results of modal masses, effective modal masses, and modal mass factors
- Visualization and animation of mode shapes
- Various scaling options for mode shapes
- Documentation of numerical and graphical results in the printout report
The equation solver includes an optimized FE mesh generator and supports the latest multi-core processor and 64-bit technology. It enables parallel calculations of linear load cases and load combinations using several processors without additional demands on the RAM: The stiffness matrix only has to be created once. The 64-bit technology and the enhanced RAM options allow for calculation of complex structural systems using the fast and direct equation solver.
The development of the deformation is displayed in a diagram during the calculation. This way, you can easily evaluate the convergence behavior.
- Creation of a pre-deformed FE mesh in RFEM
- Generation of equivalent imperfections of members as equivalent loads, considering
- the reduction factors αu and αm (Eurocode)
- the precamber rises according to buckling stress curves
- Deformation of the structure due to nodal displacement
- Generation of imperfections in accordance with:
- the load case deformations
- the buckling shapes from RF-STABILITY/RSBUCK
- Equivalent imperfections on members and sets of members (for example, columns consisting of several members)
- Visualization of generated imperfection modes
When generating a pre-deformed FE mesh in RFEM, the displacement data of each individual node are saved in the background. This can be used for the calculation of load combinations in RFEM. In order to check the generated data, the pre-deformation is displayed in tables and graphically.
If the nodes of the model are to be displaced, the node coordinates are modified directly after the generation. When generating equivalent imperfections, the module creates a normal load case, including member imperfections. To facilitate the data check, generated imperfections are displayed in result tables as well as graphically.