Dynamic Response of Tuned Secondary Systems

Abstract

Light, flexible, "secondary" systems such as piping, penthouses and antenna towers are often attached to major structures. The purpose of this study is to investigate the dynamic response of secondary systems that are tuned to a natural frequency' of the primary system. Consideration is first given to simple structural models composed of a single degree- of-freedom secondary system attached to a single-degree-of-freedom primary system. Formulas for the response of the secondary system are obtained for various damping configurations. The effects of a slight detuning of the secondary system are also examined. The response expressions are then used to develop estimates for the maximum response of the secondary system. The accuracy of these estimates is assessed in a numerical study in which the exact and approximate responses are compared. Lastly, an expression is obtained for the response of a multi-degree-of-freedom tuned secondary system attached to a multi-degree-of-freedom primary system.