I have read through the Dynpac Manual Section 2.1 on Retained Degrees of Freedom.I understand that Dynpac uses a set of master (retained) degrees of freedom, selected by the user, to extract the Eigen values (periods) and Eigen vectors (mode shapes).
However, I'm wondering if there is any further guidance on determining exactly which nodes should be selected for a particular structure.
Any help or helpful links would be appreciated.
Thanks