Dynamic response of multiply supported secondary systems

An accurate and efficient method for analysis of multiply supported, multi-degree-of-freedom secondary systems is developed. The method accounts for the effects of tuning, interaction, nonclassical damping, and spatial coupling that are intrinsic dynamic characteristics of composite primary-secondary systems. The method consists of two steps: (1) Synthesis of the modal properties of the composite primary-secondary system in terms of the known properties of the individual subsystems, and (2) evaluation of secondary system response through modal combination. Concepts from modal synthesis, perturbation theory, and random vibrations are used to produce accurate results. The method is efficient since it avoids large eigenvalue solutions, time-history analysis and floor spectra computations. It is also general, as it is applicable to a variety of stochastic or deterministic inputs. The responses of an example secondary system to seismic input are obtained directly in terms of the ground response spectrum.