Seismic response of rotating machines-structure-RFBI systems

Abstract

The seismic response of a critical rotating machine either rigidly attached to a floor or independently isolated housed within an initially aseismically designed or uncontrolled structure are investigated. A particular isolation system, the Resilient-Friction Base Isolator (RFBI), is employed. Finite element formulations of a rotor-disk-bearing model on a rigid base are developed. The equations of motion for the combined rotating machine-structure-RFBI systems are presented. Parametric studies are performed to investigate the effects of variations in system physical properties including friction coefficient, mass ratio, shaft flexibility, bearing rigidity, bearing damping and speed of rotation on the response of rotating machines for the combined rotating machine-structure-isolator systems. Comparative studies in the peak response of the rotating machine supported on various isolation systems and the corresponding fixed base system are carried out. The study indicates that the Resilient-Friction Base Isolator can significantly reduce the seismic response of rotating components to potentially damaging ground excitations. Copyright (C) 2000 John Wiley and Sons, Ltd.