FORCED RESPONSE OF STRUCTURAL DYNAMIC SYSTEMS WITH LOCAL TIME-DEPENDENT STIFFNESSES

This paper deals with a method which is meant to directly approximate the steady state response of linear differential equations with periodic coefficients under external excitations. The interest lies in the use of particular systems with time-independent characteristics (mass, damping) and with periodically time-varying stiffness. A description of the principle of the method is provided. This method has been successfully tested on a single-degree-of-freedom (s.d.o.f) example and compared to the standard Runge–Kutta method. Moreover, the parameters are assumed to be a modification of initial non-parametric systems and allow us the use of the forced reanalysis methods to improve the direct spectral method (DSM). The description of the reanalysis method is made with its implementation within the direct spectral method. Then, a practical application concerning a clamped/free beam with parametric mounts is presented to demonstrate the ability of the proposed method in the analysis of systems which have many d.o.f.s and localized parameters.