2.5.4.      Iterative Guyan Reduction

Another method for selecting master DOF is based on identifying DOF that have low mass-to-stiffness ratios and then eliminating these from the matrices using Iterative Guyan Reduction (IGR). The process is applied iteratively, starting from a large candidate set of DOF, eliminating one or more DOF at a time, reducing the matrices using Guyan reduction, and then repeating the procedure until a sufficient number have been eliminated. The procedure is conceptually very simple; and, while it has no knowledge of the target mode shapes, it does an excellent job of choosing those DOF required to represent the low frequency modes.