A SUBSTRUCTURING TECHNIQUE FOR TIME-DOMAIN ANALYSES

A substructuring technique defined in the time domain is developed for structures composed of parts that exhibit dissimilar mass, stiffness and damping characteristics. The key idea is to uncouple the structure into readily identifiable parts by treating the interaction forces manifested at the interfaces of these parts as unknowns. These interaction forces are subsequently evaluated by recourse to the equilibrium and continuity conditions that hold at the interfaces. The methodology can then be applied to either the physical or the modal coordinate level. Three advantages accrue: first, it is sufficient to do a structural identification of the individual substructures rather than of the combined system; second, one avoids the case of a nonproportionally damped structure if the individual substructures happen to be proportionally damped; and third, one works with substructures of smaller dimensions than the original combined structure. © 1990.