09-10-2014, 02:35 PM
Formulations have been proposed for estimating the seismic response of i) a linear single-degree-of-freedom (SDOF) secondary system, and ii) a multiplysupported linear, classically damped secondary system within the framework of a PSDF-based stochastic aproach while the primary system is linear and classically damped. Transfer functions have been formulated for the desired response quantity in terms of the fixed-base modes of the primary and secondary systems. The mode acceleration approach has been adopted for this purpose and thus, psuedo- static response has been considered for a given number of highfrequency modes in both primary and secondary systems. The proposed formulations do not involve the determination of the combined system properties, and those are applicable to the secondary systems with various mass ratios and configurations. Through a few example primary secondary systems and an example band-limited white noise excitation, it has been shown that the use of mode acceleration approach leads to significantly more accurate results in case of the multiply su