Hi, I'm carrying out rotordynamic analysis of a dual rotor assembly of a helicopter. I am setting up the problem as a lumped mass model on shafts by modelling the rotor blades and hub as point masses with inertia. However, I'm not able to apply Rotordynamic loads to these point masses.

I am aware that the rotordynamic loads are added through making changes in the input file. But when I define them for these point masses, it shows me an error that the "Element set assembly_lumped has not been defined". I'm confused as from the manual, rortordynamic loads are defined for rotary inertia elements too. What shall I do to solve this problem? Thanks.

PS. I have applied the ROTDYNF force on the shafts and enforced a kinematic coupling between the lumped masses and shafts. Is this a valid procedure to incorporate these loads on point masses as well?

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