1166x
004675
2020-08-27

Question

A cable structure model created in RFEM 5.13 cannot be calculated in the current version of the program. The program displays the message "Stiffness matrix is singular", although it could be calculated in the original version. How can I fix this?


Answer:
The instability appearing in newer versions of the program is caused by a change that we had to perform in the setting of the initial stiffness. This can be corrected in Calculation Parameters, under the Form-Finding tab. You use a lower FF calculation speed, which will not reduce the initial stiffness as radically, and the calculation will be more stable. In some cases, the number of FF iterations still needs to be increased.