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, the equivalent stress analysis is carried out according to von Mises. The elastic stress analysis (EL-EL) is to be performed. In RF‑/STEEL EC3, a classification is done before the design. If a cross-section is classified as Class 1 or Class 2, the design is carried out against the plastic limit internal forces. The EL-PL design is to be 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, take 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 the design is not possible. In SHAPE‑MASSIVE, it is necessary to activate the "Stresses by Stress Points" option in 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 Class 2 are designed plastically in RF‑/STEEL EC3 by default. In order to be able to compare the results with RF‑/STEEL, please activate the elastic design the cross-sections of Class 1 and Class 2 (Figure 02) in Details of RF‑/STEEL EC3.
Please also check whether the same partial safety factor γ for the resistances of the cross-sections is defined in both add-on modules (Figure 03 and Figure 04).
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 increases significantly with increasing axial force and the ratio increases exponentially in the case of the second-order analysis,, the influence of imperfection only increases linearly in relation to the axial force in the case of the equivalent member design. Therefore, there is usually a greater difference between the design ratios according to the linear static analysis by using the equivalent member method and the second-order analysis by using the stress analysis for the structural systems with very high or very low design ratio.
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. ”