Dear,n@Ashish Khemka, thank you for your answer. The problem is that the angular velocity is applied around the z-axis. The ENTIRE structure should rotate around the z-axis. Beam elements are instead in-plane elements and their axes are around x or y. I don't know if it could be the reason of my error. The other doubt is this: can I apply a costant angular velocity in a harmonic analysis?nThank you for the help.nBest regards,nFrancesca Pistorion