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)
Customer Support 24/7
AnswerIn the RF-/STEEL add-on module, an equivalent stress design is performed according to von Mises. An elastic stress design (EL-EL) is to be made. In RF-/STEEL EC3, a classification is carried out before the design. If the cross-section is classified as class 1 or class 2, the design is performed against plastic limit internal forces. An EL-PL design is performed. If you do not want to use the plastic load reserves, you can switch the design to EL-EL in the details of the RF-/STEEL EC3 add-on module. The results are then comparable with RF-/STEEL.
AnswerIn this case, it is worth taking a look at the stress points in the cross-section details. If they are not accessible (grayed out), no stress points have been defined in SHAPE-MASSIVE and design is not possible. In SHAPE-MASSIVE, the option 'Stresses by Stress Points' must be activated in the General Data. After recalculating and saving, the cross-section can be designed in the RF-/STEEL add-on module.
Cross-sections assigned to class 1 or 2 are designed plastically by RF-/STEEL EC3 by default. In order to be able to compare the results with RF-/STEEL, please activate the elastic design of class 1 and 2 cross-sections (Figure 2) in the Details of RF-/STEEL EC3.
Please also check whether the partial safety factors γ for the resistances of the cross-sections are defined identically in both add-on modules (Figure 3 and 4).
AnswerRSTAB is a pure framework program and only determines internal forces, deformations, and support reactions.On the other hand, stresses are variable depending of the cross-section and are calculated on the stress points of a cross-section. This stress determination is performed in the RF-/STEEL add-on module by calculating the existing stresses and comparing them with the limit stresses.
AnswerWhile the influence of imperfection rises significantly with the increasing axial force and the design increases exponentially, this only increases linearly equal to the increase of the axial force in the case of the equivalent member design. Therefore, there are usually stronger deviations of the structural systems with a very high and a very low utilization in the design ratios of the linear static analysis by using the equivalent member method in comparison with the second-order analysis by using the stress analysis.
AnswerIn RF‑/STEEL, the stresses are calculated on stress points of a cross-section. The stress points defined for the cross-section can be displayed in the details of the cross-section. For the cross-section shown in Figure 01, the stress points are defined along the cross-section. Thus, the stress points (here, Stress Points 1 and Stress Point 9) are also available in the roundings.In SHAPE‑THIN, you can only calculate the stresses on elements. It is not possible to calculate the stresses on the point elements that are used to model irregularities in the cross-section geometry, such as roundings and so on. The stress points of the SHAPE‑THIN cross-section are displayed in Figure 02. In the case of the cross-sections with point elements, minor deviations in stresses may thus occur due to the different stress points.Furthermore, SHAPE‑THIN provides the option to calculate the stresses for the most unfavorable element edges or for element center lines only. In RF‑STEEL, the stresses are calculated exclusively on the stress points.
AnswerThis behavior is caused by the detail settings in the RF‑/STEEL add-on module. The results of result combinations can be used in many different ways.To use the same maximum internal forces for stress analysis, the settings should be made according to Figure 01.However, this setting is very conservative because not all maximum internal forces can occur at the same time.
AnswerThe stress calculations are performed on stress points of a cross-section.
The cross-sections of the cross-section types
- Flat steel
- Square steel
- Hexagonal steel
- Octagonal steel
- Wide flats
If a member with one of these cross-sections is subjected to the shear force or torsion, it is necessary to select solid cross-sections.
With the COM interface, you can access most operating elements as well as results of the following programs or add-on modules:
- RF-/STEEL EC3
- RF-/TIMBER Pro
- RF-/DYNAM Pro
[NOT_TRANSLATED] [NOT_TRANSLATED] Once entered, stresses in the add-on module STEEL can be stressed at these cross-section points
Did you find your question?
If not, contact us via our free e-mail, chat, or forum support, or send us your question via the online form.
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.
“Thank you for the valuable information.
I would like to pay a compliment to your support team. I am always impressed how quickly and professionally the questions are answered. I have used a lot of software with a support contract in the field of structural analysis, but your support is by far the best. ”