Does the inertial force generated by the OMEGA command get updated based on the geometry change that occurs for the case with NLGEOM,ON ?
Yes. Please see the attached two element model that shows that the centrifugal force (radially outward) is based on the increased length of the beam "spinning" about the base end with a mass element at the tip end. The centripetal force is equal and opposite to the or centrifugal force. The beam is massless to make the m*R*OMEGA**2 calculation as simple as possible. The input file is fully commented and MKS units are used. A summary is shown below. With NLGEOM,OFF: ================ FX = 10000 Newtons and UX = 0.0019324 meters F = m*R*OMEGA**2, where m = 1.0 kg and OMEGA = 100 rad/sec (both constant), F = (1.0 kg) * (1.0 m) * (100 rad/sec)**2 = 10,000.0 Newtons With NLGEOM,ON: =============== FX = 10019 Newtons and UX = 0.0019416 meters F = m*R*OMEGA**2, where m = 1.0 kg and OMEGA = 100 rad/sec (both constant), F = (1.0 kg) * (1.0019416 m) * (100 rad/sec)**2= 10,019.4 Newtons = 10,019 ... 

