A real-time structural parameter modification (RSPM) approach for random vibration reduction: Part I. Principle

Earthquake-induced structural vibrations are stochastic in nature. Part I o f this study presents a novel structural control methodology for earthquake vibration reductions. It summarizes the efforts of the authors toward the development of RSPM control between 1993 and 1996. The operating control pr inciple is minimization of conservative energy. The control hierarchy is re alized by low-power-consuming devices (functional switches) with multiple r anked loops. The control method is to adjust optimally the physical paramet ers (mass, damping and stiffness) of the structure in real time. This metho d is therefore described as real-time structural parameter modification (RS PM). It may be called variable passive control or parametric control. The b asic thesis of RSPM is presented, together with a discussion of the minimal principle of conservative energy of a vibrating system and the RSPM contro l hierarchy which contains four ranked loops. Variable passive control is c apable of handling the stochastic nature of earthquake ground motion and it does not have certain major drawbacks of conventional active control metho ds. Part II of this study will describe the experimental verifications of R SPM. It will be shown that RSPM can dissipate considerably more energy than existing passive energy dissipation devices. In addition, RSPM can reduce vibrations resulting from multi-directional excitations. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.