Rel_motion is only working in the time domain. There is not an equivalent in the frequency domain. This is because of the assumptions in the frequency domain.
For one body we can calculate the phase between the motions. The frequency domain method does not include phase between two bodies.
The user can report the frequency domain motions with st_point. Frequency domain is based on statistics/probability. The intent is for statistics of one body at a time to be reported. The user can designate the points on each body then ask for a report separately. It is up to the user to decide how to combine the results.
Fisyah.zainon@bentley.com
Not sure, but I thought you could get that from FR_POINT *P_BODY1 *P_BODY2, and statistics would be available by issuing ST_POINT after that.
Dear Lars Rune Helland,
Yes, the point motion statistics computed at is the point specified in fr_point command.
Furthermore, if you have two bodies, you should let MOSES know which body you are working on by issuing the "&describe body" command.
I mean, if you are trying to get the motion statistics of "body1", you should issue the "&describe body body1" before "fr_point" and "st_point" command. Same for the other body.
I would like to recommend you to run the analysis in time domain then issue the rel_motion command if the relative distance between the points is of important since motion statistics of each body does not have any phase.
Best regards,
Bitna
Hi! I'm not doing any analyses. My comment was a response to the original question regarding relative motion. To elaborate: FR_POINT *PNT1 gives you the frequency response of the motion of the point. If you specify two points and not one, you obtain the RELATIVE motion of the two points, which was the original question.
HI Lars,
Thank you so much for keeping up with these topics.
Yes, even I had forgotten about putting two points after the fr_point command.
georgina