Answer:
- In most cases, these differences can be attributed to a lack of convergence. Increasing the number of iterations and increments in the calculation parameters and FE mesh settings should help (see Image 01).
- High jumps in stiffness result in numerical problems, which lead to errors in the results evaluation. In RSTAB, this is not a major problem for a complete and analytical approach function. In RFEM, on the other hand, approximation approaches are used, which are more likely to prevent high stiffness changes. An example of this are rigid members (very high stiffness) that are connected to softer surfaces or members. In this case, the rigid member can be replaced by a beam member with a stiff cross-section or by means of stiffness members with high stiffness.
- In case of members with elastic foundations, deviations may occur as well. If the members are not divided or only roughly divided, convergence problems occur. A practical solution is to select a "finer" distribution of members in the FE mesh settings (see Image 02).
- In the case of non-linear systems, changing the type of calculation can also help (see Image 03).
