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  • Answer

    It is possible to transfer the login data via the command line parameters. Then, the login window will no longer appear at start-up.

    It looks like this, for example:

    RFEM6.exe --email [email protected] --password Trurvzrf_Cnffjbeg

    You can add these parameters directly to the links to RFEM on the desktop:

  • Answer

    Accuracy of RWIND Results and Ratio of Accuracy Versus Cost

    The RWIND program was designed to quickly and easily calculate wind flow around buildings in order to obtain pressure values on their surfaces and generate load forces. In order to meet this main goal, a number of compromises had to be made, such as allowing the use of a simplified model or a relatively coarse computational mesh. It is obvious that these simplifications affect the accuracy of the results. Increasing the accuracy of the results using a finer mesh and other user settings in RWIND is possible, but this process may not be easy and requires sufficient experience with CFD simulations. An important question here is what is the acceptable ratio of effort and cost to the improvement in accuracy achieved. We recommend reading the CFD Project Accuracy vs. Effort article which deals with this issue in detail.

    RWIND Error E315

    When increasing the mesh density, memory and performance requirements do not grow linearly, but with the 3rd to 4th power (we have three spatial dimensions and also a reduction of the time step is necessary). This not only leads to a significant slowdown of the calculation, but also various problems can start to appear, which are usually related to the fact that the program approaches its limits or the limits of the hardware used. These problems also include error E315 which indicates a general failure inside the OpenFOAM© calculation modules – such as memory allocation failure, loss of numerical precision, and so on. The specific reasons for the failure can be different. More detailed information can be found from the relevant Log File.

    RWIND Customer Support and its Limits

    Dlubal customer support always tries to help RWIND users who encounter any problems. However, numerical simulations of wind flow can be very complex and results cannot generally be guaranteed. This is due to the fact that there is still no mathematical proof of the existence and uniqueness of the solution of the Navier-Stokes equations that describe this flow and which RWIND solves numerically using the finite volume method. Although the calculation converges to the correct solution in most cases, a failure of the calculation cannot be excluded. In the event that a calculation failure occurs in a large and complex project, assistance can be very time-consuming. If you are interested in additional extended assistance, please Contact Our Sales Team.

  • Answer

    If you are using RFEM 5 or RSTAB 8, click the "About RFEM and Licensing" entry in the Help menu. You can find your customer number here:

    In RFEM 6 or RSTAB 9, click the "System Information" entry in the Help menu. You can find your customer number here:

  • Answer

    In the RSECTION program, you can analyze general steel or aluminum cross-sections and determine the effective section properties. For this, you need the Effective Sections program extension of RSECTION. If you have licensed this add-on, you can activate the Effective Section option for the calculation in the Base Data of the cross-section.

    Then, define the standard according to which the calculation should be performed. Currently, the following options are available:

    • EN 1993-1-1 and EN 1993-1-5
    • EN 1993-1-3 (Cold Formed)
    • EN 1999-1-1 (Aluminum)

    The effective section properties depend on the internal forces of the cross-section. Therefore, create a load case and define one or more internal force constellations.

    After the calculation, the effective section properties are displayed in the table. In the graphic, you can check the stresses on the effective section.

    Once you have saved the cross-section, you can import it into RFEM or RSTAB to use it for further analyses.

    The webinar Determination of Section Properties and Stress Analysis in RSECTION shows the modeling and calculation of a cold-formed section. You can find further information there.

  • Answer

    Both RFEM and RSTAB are available for the structural analysis and design of temporary structures, such as carousels, roller coasters, stages, or grandstands. There are add-ons available for both main programs that you can use to design steel, aluminum and lightweight structures according to various standards. If you also want to analyze membrane and cable structures, RFEM is your tool of choice.

    Main Programs RFEM and RSTAB

    The main programs RFEM and RSTAB are used to define the model with its properties and actions. RFEM proves to be the more versatile option, as it can be used to analyze structures with surface components, such as membranes, in addition to pure member structures.

    Available Standards

    For the design of steel beam and cable structures, the following standards are available:

    • EN 1993 (Eurocode 3)
    • BS 5950 (British standard)
    • AISC 360 (US standard)
    • SIA 263 (Swiss standard)
    • IS 800 (Indian standard)
    • GB 50017 (Chinese standard)
    • CSA S16 (Canadian standard)
    • AS 4100 (Australian standard)
    • NBR 8800 (Brazilian standard)
    • SP 16.13330 (Russian standard)

    Aluminum structures can be designed according to the following standards:

    • EN 1999 (Eurocode 9)
    • ADM (US standard)
    • GB 50429 (Chinese standard)

    Analysis and Design Add-ons

    Design add-ons supplement the functionality of the main programs. In the design add-ons Steel Design and Aluminum Design, you can perform the ultimate and serviceability limit state design, as well as the stability analysis according to the standards listed above.

    In the case of membrane and cable structures, the Form-Finding add-on facilitates your task to determine the shape of member and surface models subjected to axial forces. On the other hand, you can use the RWIND program to perform simulations in the digital wind tunnel for complex structures and to transfer the generated wind loads to RFEM.

    Dynamic Analysis

    If you need to perform a seismic or vibration analysis, the corresponding Dynamic Analysis add-ons are the perfect tools for determining natural frequencies and mode shapes, or for the analysis of external excitations.

    In case of any questions about the Dlubal solution for temporary structures, our sales team will be happy to assist you.

  • Answer

    The programs RFEM 6 and RSTAB 9 are connected to a personal Dlubal account. This also applies to the viewer or demo mode. To ensure that your partner can create a new account, all they need to do is to enter their email address and password.

    After starting the trial or demo version and logging in, your partner can open the model. The usual view functions are available for viewing objects. However, the model cannot be edited, calculated, or saved.

    Results can only be viewed in the same program version as the model was saved in!

  • Answer

    The choice between steady-state (by using RWIND Basic) and transient simulation (by using RWIND Pro) depends on the specific requirements of the wind analysis, the level of accuracy needed, and the computational resources available. Steady-state simulations are suitable for simpler, time-invariant analyses, while transient simulations are necessary for capturing the dynamic behavior of wind flow and its impact on structures over time, and are more accurate than steady-state simulation.

    Parapets present a unique challenge in the analysis of wind loads on buildings due to their positioning and the complex flow patterns they generate. Their interaction with wind loads is influenced by several factors that contribute to their complicated behavior:

    Height and Exposure

    Parapets extend above the main roof level, exposing them to higher wind velocities and different flow patterns compared to lower parts of the building. This exposure means they can experience significantly different wind pressures, including uplift forces.

    Geometry and Shape

    The shape of the parapet—whether it is flat, crenellated, or has other architectural features—can affect how wind flows over and around it, leading to complex patterns of vortices and turbulence. These flow patterns can alter the distribution and magnitude of wind pressures on the parapet and adjacent roof areas.

    Interaction with Building Shape

    The overall shape of the building influences how wind flows around it, which in turn affects the wind loads on the parapet. For instance, wind flowing over a streamlined, aerodynamic building will behave differently from wind encountering a building with a more bluff body. This interaction can lead to areas of higher pressure or suction on the parapet that are difficult to predict without detailed analysis.

    Vortex Shedding

    Tall parapets on high-rise buildings can experience vortex shedding, where alternating vortices are shed from either side of the parapet, leading to oscillating pressures that can cause structural vibrations. These effects are highly dependent on the wind speed, parapet shape, and the building’s orientation to the wind.

    Gust Effect

    Parapets can be subjected to gusting effects, where short-duration increases in wind speed cause fluctuating loads. These transient effects are particularly important for the structural design of parapets to ensure they can withstand sudden wind load increases without failure.

    Given these complexities, advanced simulation techniques such as computational fluid dynamics (CFD) are often employed to accurately predict the wind loads on parapets. Both steady-state and transient simulations play a role, but transient simulations provide a more detailed understanding of how parapets respond to varying wind conditions over time in RWIND 2 Pro. These simulations can capture the instantaneous effects of gusts, the development of vortices, and the impact of turbulent flow, which are critical for designing parapets to be both functional and safe under wind loading.

  • Answer

    RFEM or RSTAB are the ideal basis for the calculation of scaffolding or rack structures, such as high-bay warehouses. It is also possible to consider nonlinear properties of members and hinges, such as yielding, tearing, slippage, or special scaffolding diagrams. There are add-ons available for both programs that you can use to design steel or aluminum structures according to various standards.

    Main Programs RFEM and RSTAB

    The main programs RFEM and RSTAB are used to define the model with its properties and actions. RFEM proves to be the more versatile option, as it can be used to analyze structures with surface components in addition to pure member structures.

    Available Standards

    For the design of steel beam structures, the following standards are available:

    • EN 1993 (Eurocode 3)
    • BS 5950 (British standard)
    • AISC 360 (US standard)
    • SIA 263 (Swiss standard)
    • IS 800 (Indian standard)
    • GB 50017 (Chinese standard)
    • CSA S16 (Canadian standard)
    • AS 4100 (Australian standard)
    • NBR 8800 (Brazilian standard)
    • SP 16.13330 (Russian standard)

    Aluminum structures can be designed according to the following standards:

    • EN 1999 (Eurocode 9)
    • ADM (US standard)
    • GB 50429 (Chinese standard)

    Analysis and Design Add-ons

    Design add-ons supplement the functionality of the main programs. In the design add-ons Steel Design and Aluminum Design, you can perform the ultimate and serviceability limit state design, as well as the stability analysis according to the standards listed above.

    The Torsional Warping (7 DOF) add-on allows you to also perform lateral-torsional buckling analysis with up to seven degrees of freedom. The Stress-Strain Analysis add-on provides the option for general stress design checks, where the existing stresses are compared to the limit stresses.

    Dynamic Analysis

    If you need to perform a seismic or vibration analysis, the corresponding Dynamic Analysis add-ons are the perfect tools for determining natural frequencies and mode shapes, or for the analysis of external excitations.

    In case of any questions about the Dlubal solution for scaffolding and rack structures, our sales team will be happy to assist you.

  • Answer

    Both RFEM and RSTAB are ideally suited for the structural analysis and design of power plants and conveyor structures. Depending on the requirements, you can use the add-ons from various industries, such as concrete structures or steel structures.

    Main Programs RFEM and RSTAB

    The main programs RFEM and RSTAB are used to define the model with its properties and actions. For this, RFEM provides more extensive options, as the finite element analysis can also be used for modeling and designing planar structural components.

    Add-ons for Power Plants and Conveyor Structures

    Various add-ons supplement the functionality of the main programs. In the design add-ons Steel Design and Concrete Design, you can perform the ultimate and serviceability limit state design, as well as the stability analysis according to various standards.

    The Torsional Warping (7 DOF) add-on allows you to also perform lateral-torsional buckling analysis with up to seven degrees of freedom. The Stress-Strain Analysis add-on provides the option for general stress design checks, where the existing stresses are compared to the limit stresses. For the plastic design checks, we recommend the Nonlinear Material Behavior add-on.

    Dynamic Analysis

    If you need to perform a seismic or vibration analysis, the corresponding Dynamic Analysis add-ons are the perfect tools for determining natural frequencies and mode shapes, or for the analysis of external excitations.

    In case of any questions about the Dlubal solution for power plants and conveyor structures, our sales team will be happy to assist you.

  • Answer

    Both RFEM and RSTAB provide solution: There are numerous European and international standards as well as add-ons available for both programs that can facilitate your daily design work of aluminum and lighweight structures.

    Main Programs RFEM and RSTAB

    The main programs RFEM and RSTAB are used to define the model with its properties and actions. In addition to spatial beam structures, such as scaffolding or frame structures, you can also model membrane structures with RFEM. Thus, RFEM is the more versatile variant—especially if you work in other areas, such as solid construction.

    Available Standards

    • EN 1999 (Eurocode 9)
    • ADM (US standard)
    • GB 50429 (Chinese standard)

    Add-ons for Aluminum and Lightweight Structure

    Design add-ons supplement the functionality of the main programs. Use the Aluminum Design add-on to perform the ultimate and serviceability limit state design, as well as the stability analysis according to the standards listed above. The Torsional Warping (7 DOF) add-on allows you to also perform lateral-torsional buckling analysis with up to seven degrees of freedom.

    The design checks can be carried out for a large number of standardized and parameterized cross-sections. Lightweight structures often includes special cross-sections, such as extruded sections. You can define it with the program RSECTION and use it for the design in RFEM or RSTAB.

    In the case of membrane and cable structures, the Form-Finding add-on facilitates your task to determine the shape of member and surface models subjected to axial forces.

    In case of any questions about the Dlubal solution for aluminum and lightweight structures, our sales team will be happy to assist you.

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Contact Dlubal

Unable to find the answer to your question? Contact us via phone, email, chat, or forum, or send us your question directly through our online form.

+1 267 702-2815

[email protected]

First Steps

First Steps

Check out these tips to help you get started with the RFEM and RSTAB programs.

Wind Simulation & Wind Load Generation

It's getting windy here! Send your structures to the digital wind tunnel using the stand-alone program RWIND 2. It simulates wind flows around structures, regardless of whether they are simple or complex.

You can easily import the generated wind loads acting on these objects into RFEM or RSTAB and use them for your further calculations.


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I would like to pay a compliment to your support team. I am always impressed how quickly and professionally the questions are answered. In the industry of structural analysis, I use several software including service contract, but your support is by far the best.”