Partitioned Component Mode Synthesis via a Flexibility Approach

A new flexibility-based component mode synthesis method is presented, which is derived by approximating the partitioned equations of motion that employ a localized method of Lagrange multipliers. The use of the localized Lagrange multipliers leads to, unlike the classical Lagrange multipliers, a linearly independent set of interface forces without any redundancies at multiply connected interface nodes. Hence, the resulting interface flexibility matrices are uniquely determined and well suited for the present method development. An attractive feature of the present method is its substructural mode selection criterion that is independent of loading conditions. Numerical experiments show that the present modal selection criterion is reliable and that the proposed flexibility-based component mode synthesis method performs well relative to the classical Craig-Bampton method in terms of accuracy and of its ability to include dominant substructural modes for simple plates and a relatively complex solid ring.