2034x
001278
2017-03-17

Signed Results Using Dominant Mode

The loss of signs follows from the quadratic result combination. Internal forces at different positions in the model can only be provided as a result envelope where the maxima are all positive and the minima are all negative. The result combination is not unique.

To produce a more realistic figure of internal forces, the signed results combination option has been introduced. Equivalent loads corresponding to each eigenvalue and mode shape are exported to RFEM or RSTAB, into Load Cases. The results in Load Cases are always unique.

If the structure you are considering has a dominant eigenvalue (large effective modal mass factor), the signs of the corresponding Load Case can be applied on the results in the Result Combination. Using this option, the Result Combination becomes unique, too.

RF-DYNAM Pro - Equivalent Loads can select the dominant mode automatically by means of the largest effective modal mass factor, but you can also select a mode manually. In the exported Result Combination, the option "According to LC/CO" is automatically selected and the correct Equivalent Load Case is set.

Independent of RF-/DYNAM Pro, this option is available in RFEM/RSTAB for any Result Combination that uses the quadratic combination. The Maximum and Minimum calculation parameters are extended by the option "According to LC/CO".

Further notes and an example are shown in the figure.


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