Extranet | News | Support | Contact us | Legal Notice
Deutsch | English | Français | Español | Português | Italiano | Česky | Polski | Русский  


Answers to frequently asked questions  


Purchase Decision (17) Installation (14)
Input (65) Calculation (86)
Display (63) Printout Report (28)
Archive, Backup (7) Import, Export (11)



Category Calculation

1. Because I have to design a very irregular structural system for earthquakes, I would like to know if RFEM performs the so-called modal analysis (considering several mode shapes) automatically on the spatial system, or if it needs a special setting. RFEM DYNAM Addition II
I have modeled a simple cable structure with prestress where the support forces are smaller than the prestressing force. To check it, I have analyzed two different spatial systems.

Example 1 is defined with a straight cable while the cable of example 2 has a rise.

Where does the difference come from?
3. When do I apply the different equation solving methods with "direct" and "iterative"? RFEM
4. The calculation of the critical load factor according to second-order analysis in RSTAB results in a value that differs significantly from the one of the RSBUCK calculation. RSTAB RSBUCK
5. Where are the limits for RSTAB concerning the number of structural elements? RSTAB
I noticed an inconsistency for the determined result combinations. For example, why is the maximum vertical support reaction of RC4 zero?

In my clear system, I can easily see that this cannot be true. The minimum load is alright. 
7. Why the program doesn't show any total displacement for result combinations? RFEM RSTAB
I have idealized a taper by using a start and end cross-section (calculated with SHAPE-THIN). Then, I have calculated the frame.
When I carry out the stress calculation in STEEL, the error message "Tapered member contains incompatible cross-sections" appears.

What can be the cause of the error?
When I tried to pick the imperfections in FE-LTB, the message "Diagonal coefficient of matrix < 0" was displayed.

What have I done wrong?
I have inserted a predeformation in RSTAB.
FE-LTB takes over the loads if desired, why not also the pre-deformations?


On this page you find answers to frequently asked questions provided by Dlubal hotline engineers and also solutions to often encountered problems.

In case you still have not found what you are looking for, you can always ask questions. We will try to help you.
Feel free to ask...

Help for Beginners

Find useful information to get started with our programs RSTAB and RFEM: introductory examples, videos, webinars etc.
First steps...
Follow us on:   Facebook   Google+   Twitter   YouTube   LinkedIn   Pinterest   Blog      E-mail
© 2015 Dlubal Software GmbH - All rights reserved