Vibration and Damping Characteristics of Cable-Stayed Bridges Tower Control

摘要

This study presents a technique for the optimal design of composite structures made of differentmaterials with the purpose of reducing vibration amplitudes at dynamic loads. The characterizationof damping is important in making accurate predictions of both the true response and the frequencyresponse of any structure dominated by energy dissipation. It is also necessary to design thestructure to be controlled for optimum performance. The process of modeling damping matrices andexperimental verification is challenging because damping can not be determined via static tests ascan mass and stiffness. The stiffness and mass distributions are quite well determined, but there isgreat uncertainty regarding the energy dissipating mechanism provided by the damping of thestructure because it is the least well understood, the damping must be estimated. The assumption ofclassical damping is not appropriate if the system to be analyzed consists of two or more parts withsignificantly different levels of damping, such as structure soil system. The dynamic response ofstructures is critically determined by the damping mechanisms, and its value is very important forthe design and analysis of vibrating structures. The effect of damping on the natural frequencies oftower structure is discussed. It is shown that in classically damped systems increasing the dampingdecreases the natural frequencies of the system; with non-classical damping some of the naturalfrequencies of the damped system may be greater than the corresponding natural frequencies of theun-damped system.