In addition to our technical support (e.g. via chat), you’ll find resources on our website that may help you with your design using Dlubal Software.
Frequently Asked Questions (FAQ)
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AnswerYou have probably selected too few mode shapes in the "Natural Vibration Cases" window of RF‑/DYNAM Pro. In this case, it may happen that the defined mode shapes do not vibrate in all directions and thus no mass is excited in these directions.Therefore, you should calculate at least so many mode shapes that the required 90% of the mass is excited in each direction in your calculation.This is also described in more detail in the FAQ under the link below.
AnswerWhen defining an imperfection, there are four options available for activating the precamber.
The attached example video shows that the limit slenderness is not exceeded for the middle column. No imperfection is applied. The bending moment Mz is zero.
The precamber is always taken into account.
- EN 1993-1-1 (5.8)
The precamber is only taken into account if the slenderness ratio is greater than in Formula (5.8) of the standard EN 1993‑1‑1 (see Figure 01).
- DIN 18800 (207)
For the calculations of existing buildings, this option according to the withdrawn standard DIN 18800 was left in the program.
Here, you can specify a value for the member coefficient ε0. The member coefficient is determined according to the formula in Figure 02.
This message appears if all defined natural vibration cases or dynamic load cases have already been calculated. The reason is that the check only goes through the input data that have not yet been calculated.
So it can be said that the check should only be applied before the calculation. If there are any input errors, the calculation cannot be performed anyway.
Please check the integrated lines or the automatic object detection within the "Integrated" tab of the "Edit Surface" dialog box (see Figure 01).
In some cases, the automatic object detection is deactivated during the model editing. Therefore, make sure that the corresponding lines are integrated into the surface.
In the calculation parameters of RFEM or RSTAB, there are the "Number of load increments for load cases/load combinations" text boxes under the "Global Calculation Parameters" tab. These two entries control the numerical incremental application of the defined load boundary conditions in the respective load cases and load combinations. The reciprocal value of the entry describes a fraction of the load. The solving process then applies the defined load fractions successively to the model in so-called load increments until the complete load is reached. In the respective load increments, the equation solver tries to find an equilibrium within the maximum allowed iterations, and thus to specify suitable start values for the next load increment.
It is possible to imagine that the solving process collects the complete load of a load case or a load combination in a "watering can" and pours it onto the load-collecting model in portions. In this case, the number of load increments correlates with the speed of the load application. The speed is not to be understood as a real time parameter, but purely numerically.
The incremental load application has only an effect in the case of nonlinear structural systems. It usually provides a correspondingly higher result quality with increasing number of load increments. The basic aim of this method is to find a micro convergence in the respective load increments to specify new high-quality start values for the next load increment, and thus finally to achieve a macro convergence for the entire load case.
You can find our current offer of online training always updated on our website under the following link:
Select the relevant training session and click the "Register" button at the bottom. A form appears, where you should enter your personal details, e-mail address, and company data. The next page provides you with a brief overview or the confirmation of your registration, and the information about the training price whether the training is liable to pay. In the case of the training liable for costs, you can proceed with the payment and use either PayPal or one of the following credit cards:
- American Express
Please ensure that your credit card is activated for the relevant amount and that the details are entered correctly.
Sometimes, credit cards are not accepted. The reasons for this may be:
- The network settings have the restrictions that prevent from using online payment systems. In this case, use another network, for example, on your cell phone.
- Antivirus programs block the usage of the online payment system.
- Your credit card does not have the required transaction volume.
If the problems cannot be solved, please contact us.
Yes, you can quickly create surfaces, grids, or girder grillages by extruding lines and members. However, if you want to generate an irregular grid with extended specifications, the Generate Grid dialog box is recommended.
In our case, we would like to create a regular grid by using the Extrude Member into Grid function.
In the Extrude Member into Grid dialog box, you can specify various settings.
As a result, we obtain the desired grid and can thus continue modeling.
AnswerIf you use the "Within cuboid - general" integration option, the reason may be incorrectly defined parameters for the application area. The application lengths must be entered as an amount. This is especially important in the negative direction: If you enter the application length as a negative value, this value is subtracted from the positive direction.Example: You want to define an integration area of 1 m for the result beam. For the "Within cuboid - quadratic" option, simply enter an application length of 1 m. In the case of the "Within cuboid - general" option, you have to enter a length of 0.5 m as the amount in both the positive and the negative direction. These lengths are added together and you get a total application area of 1 m.
In the detail settings of the respective result beam, you can specify which objects (members, surfaces, or solids) are to be considered by this result beam.
For example, if there is an unexpected result displayed for the result beam, you should check in this dialog box whether the integration area has been set correctly for the objects.
In the details of all add-on modules, you can control the display of result tables. In this case, it is helpful to only display the results by load case or by material.
In the RF‑STEEL Surfaces add-on module, it is also possible to perform the calculation of enveloping values only.
Furthermore, it may be helpful to display the results in grid points. For the RF‑LAMINATE add-on module, it is also possible to completely hide the results of the grid points. A detailed description of this can be found here .
The settings for the RF‑STEEL Surfaces add-on module are shown in Figure 01.
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Wind Simulation & Wind Load Generation
With the stand-alone program RWIND Simulation, wind flows around simple or complex structures can be simulated by means of a digital wind tunnel.
The generated wind loads acting on these objects can be imported to RFEM or RSTAB.
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