Forced response of structural dynamic systems with local time-dependent stiffnesses

This paper deals with a method which is meant to directly approximate the s teady state response of linear differential equations with periodic coeffic ients under external excitations. The interest lies in the use of particula r systems with time-independent characteristics (mass, damping) and with pe riodically time-varying stiffness. A description of the principle of the me thod is provided. This method has bean successfully tested on a single-degr ee-of-freedom (s.d.o.f) example and compared to the standard Runge-Kutta me thod. Moreover, the parameters are assumed to be a modification of initial non-parametric systems and allow us the use of the forced reanalysis method s to improve the direct spectral method (DSM). The description of the reana lysis method is made with its implementation within the direct spectral met hod. Then, a practical application concerning a clamped/free beam with para metric mounts is presented to demonstrate the ability of the proposed metho d in the analysis of systems which have many d.o.f.s and localized paramete rs. (C) 2000 Academic Press.