US-Tunisia Cooperative Research: Vibration Confinement in Seismically Excited Linear and Hysteretic Structures

Virginia Polytechnic Institute And State University, Blacksburg VA

Investigators

Abstract

0138083 Nayfeh Description: This award supports a cooperative research project between Professor Ali Nayfeh, Department of Engineering Sciences and Mechanics, Virginia Polytechnic Institute and State University (VA Tech.), Blacksburg, Virginia and Dr. Sami El-Borgi, Department of Engineering, Ecole Polytechnique de Tunisie (EPT), Tunis, Tunisia. The investigators will examine the control of a seismically excited linear elastic or hysteretic structure by passive confinement of vibrations. The objectives of the research are: a) to develop a passive control strategy which allows the transfer of the vibrational energy from the structure to added passive elements, such as diagonal bracing elements, resulting in reducing the vibration amplitudes of the structure and bringing it down to its desired equilibrium state more rapidly at the expense of slowing down the convergence of the passive elements to their initial state; b) to ensure the sensitivity robustness of such a strategy against parameter uncertainties related to the mass, damping, and stiffness of the structure; and c) to preserve the vibration confinement in the passive elements for various types of seismic loadings. Scope: The protection of structures from harmful earthquake and/or wind vibrations is a worldwide issue. The control of seismically excited structures by confinement of vibrations with the aid of passive elements is a novel design methodology in civil engineering applications. The idea is relevant to various fields, such as mechanical systems and multi-floor buildings. Dr. Nayfeh has been quite active in research on linear and nonlinear control of dynamical systems. He will collaborate with Dr. El-Borgi and two other Tunisian faculty members. Dr. El-Borgi has been quite active in nonlinear analysis and control of seismically excited structures and experimental testing of large civil engineering structures. Funding is provided by the Office of International Science and Engineering and the Division of Civil and Mechanical Systems.