Yu Bi
Ansys Employee
Hi, thanks for your question. As you described your model as multibody, I assume you meant the model has hydrodynamic interactions. If so, there are two points I may suggest you have a check. First is for the added mass and damping. Please make sure all the non-diagonal matrices (the interaction terms) have been included in your calculation. The next is the exciting force on the right-hand side. In the *AH1 file, the forces are at the COG of each structure. When you calculate the RAOs, you need to transfer the phase of the force at the COGs of different structures to a common point. Otherwise, the result will not be right.nHope this helps.nKind regards n