It is trivial to setup a frequency response run to obtain the Graph (Inertance Vs. Frequency) and identify the Torsional mode excitation once you have loading as function of frequency available. (in this instance it can be unity). Beyond that, the calculation of the result interpretation and the rigidity is left to the engineer. Nastran does not directly produce the rigidity results. I will leave it to others on this forum who has experience in extracting "rigidity" from frequency response results to comment further.
You may find the following link useful in setting up the frequency response problem in nastran/patran.
It is trivial to setup a frequency response run to obtain the Graph (Inertance Vs. Frequency) and identify the Torsional mode excitation once you have loading as function of frequency available. (in this instance it can be unity). Beyond that, the calculation of the result interpretation and the rigidity is left to the engineer. Nastran does not directly produce the rigidity results. I will leave it to others on this forum who has experience in extracting "rigidity" from frequency response results to comment further.
You may find the following link useful in setting up the frequency response problem in nastran/patran.
