Twenty years of structural dynamic modification: A review

Structural dynamic modification techniques have been available as a design tool for several decades now. The overall methodology of the technique is reviewed including both proportional and complex mode formulations. Issues pertaining to limitations on its use and truncation effects of unmeasured modes are discussed. Also discussed are the use of simplistic elements through higher order elements. Discussion on typical commercial implementations are presented. The ever constant problem associated with the lack of rotational DOF and truncation and attempts to overcome those issues are presented.