In the add-on module RF-/DYNAM Pro – Equivalent Loads, you can perform seismic analyses with multi-point response spectra analysis. The required spectra can be created according to the standards or user-defined, from which the equivalent static loads are generated.
With the add-on module RF-/DYNAM Pro – Forced Vibrations, you have the possibility to dynamically analyze a supporting structure with regard to external excitation. You can define the various excitation functions by using time history analysis, accelerations (accelerograms) or harmonic loads and link them with load cases.
With the multi-modal as well as with the multi-point response spectra analysis, you can perform seismic analyses. The required spectra can be created according to the standards or user-defined. The add-on module contains an extensive library of accelerograms from earthquake zones. They can be used to generate response spectra.
With the add-on module RF-/DYNAM Pro – Natural Vibrations, it is possible to quickly and conveniently analyze natural frequencies and mode shapes for spatial models. All required input values can be imported directly from RFEM or RSTAB. Powerful eigenvalue solvers (sub space and shifted inverse iteration) are available to determine up to 9,999 eigenvalues.
By Wieland Götzler, Dlubal Software
With the versions of RFEM 5.04.0024 and RSTAB 8.04.0024, it is possible to define the antenna ice loads in RF-/TOWER Loading. The program provides values from manufacturer databases. In addition, you can define the ice loads manually or use the calculation based on the simplified geometry.
By Walter Fröhlich, Dlubal Software
1. The most common cause of unstable models represent failing member nonlinearities such as failure of tension members.
As the simplest example, there is a frame with supports on the column footing and moment hinges on the column head. This unstable system is stabilized by a cross bracing of tension members. In the case of load combinations with horizontal loads, the system remains stable. However, if it is loaded vertically, both tension members fail and the system becomes unstable, which causes a calculation error.
You can avoid such an error by selecting the exceptional handling of failing members under “Calculate” -> “Calculation Parameters” -> “Global Calculation Parameters”.
2. Another cause of unstable models are failing supports or foundations.
For example, the system of a building with support or foundation failure becomes unstable usually when calculating wind load cases.
You can avoid the error by calculating the individual load cases always together with the self-weight in one CO, not separately.
3. Too weak systems can also cause the instability in a CO.
If the load for the specified cross-section/surface thicknesses is too big that the program cannot find equilibrium in the deformed system, a calculation error occurs.
You can check this by selecting the Geometrically linear static analysis under “Calculate” -> “Calculation Parameters” -> “Load Combinations” tab for the problematic CO. The deformation according to the geometrically linear static analysis itself is usually too big and the dimension of the elements has to be increased.
4. If instability occurs despite compliance with the points specified above, the cause is probably errors in modeling.
In this case, click “Tools” -> “Model Check” and check if there are identical nodes, overlapping lines/members/surfaces or crossing unconnected lines/members. Especially in the case of imported systems, it often happens that the elements are unconnected due to rounding differences. You should also check the boundary conditions such as hinges and supports.
By Stefan Frenzel, Dlubal Software
In RFEM and RSTAB, it is now also possible to create concentrated member and line loads. This is an extension of the original member/line load function. From now on, you can create several concentrated loads with uniform or user-defined load distribution on a member or a line.
By René Flori, Dlubal Software
In rare cases, it may happen that an RFEM or RSTAB file cannot be opened. These files mostly contain results and report data. In order to eliminate problems caused by the result data or report information that are no longer readable, you can delete the data in the project manager without opening the corresponding project. Structural data, loads and defined combinations remain preserved.
By Andreas Hörold, Dlubal Software
The new headquarters of the Baden farmers’ association (BLHV) is unique. The timber construction is protected by a glass façade to counteract graying caused by weather conditions. Although the architects of the Werkgruppe Lahr have sufficient experience in timber construction, the wooden house with the glass cladding has been a “model project” for them.
Dlubal RFEM 5 & RSTAB 8 – Editing Reinforcement in CONCRETE/RF-CONCRETE Members Directly in Graphical Window
By Moritz Bertram, Dlubal Software
It is now possible to edit a reinforcement layout or existing reinforcement directly in the 3D rendering of the reinforcement. For this purpose, there is a dialog box available that you can easily open by double-clicking the reinforcement position to be edited. Moreover, you can copy or delete the reinforcement directly in the window.
Once you finish the editing process, the reinforcement case is recalculated.
Calculations performed by Dlubal programs provide clear results, which is not only appreciated by test engineers checking analysis documentation. As an engineer you want to know exactly how the software works. Dlubal software is not a black box. The verification examples give you an insight into the analysis background. Additionally, the design methods are described in detail.