Redesigning the dynamics of structural systems

The critical link between two powerful modeling techniques, component mode synthesis and large admissible perturbation theory, is established. This ne w redesign process allows structural systems that are composed of several s ubstructures to be redesigned. The process is developed in three steps, Fir st, the analytical first-order perturbation relationships between the struc tural system eigenvalues and the eigenvalues of each independent substructu re are developed, Second, a transformation matrix is developed for each per turbation relationship, then combined to form the ultimate structural trans formation matrix. Third, a minimization problem is defined that uses the ul timate transformation matrix as a set of constraint equations. The result o f this minimization is a set of changes to the substructure eigenvalues tha t approximately affect the objective changes to the structural system eigen values. The success of the redesign process is demonstrated by an isolated platform example, The changes in the substructure eigenvalues are predicted via the redesign process, then substituted back into the full nonlinear eq uations for the structural system, and the results are discussed. This work forms the basis for future redesign developments when other static and dyn amic objectives are to be achieved for structural systems.