Application of the Gradient Based Optimization to the Structural Systems with the Supplemental Damping Devices

Abstract

AbstractEven though there are so many studies upon optimization of supplemental damping devices integrated to structural systems, the vast majority of them remain only as a subject of the research articles of the Journals and cannot find a place itself in common practice due to lack of the regulations about the issue in codes and standards. In this paper, the issue is dealt with the most fundamental inputs and outputs of a general problem. All efforts are made to show how the procedure could frequently be used in common practice and what the attained benefits could be from the design and application point of view. The analysis of the structural systems in which the “seismic response control systems” have been adapted requires considering the special numerical analysis techniques which provide “solutions in frequency domain”. By this means, not only the “dynamic response characteristics” of the structure shall be determined but also the variation of this response with the change of the “design parameters forming the structural control systems” shall be able to be investigated from the optimization point of view. Since conventional analysis tools and methods are not capable of providing such information, advanced numerical analysis method based on the “state-space approach” is considered along with the “gradient based optimization algorithm” in the proposed study. In this paper, viscous fluid dampers are examined as a supplemental damping devices in the analysis of a multi degree of freedom structure. Dampers are modelled with the Maxwell model in which the spring and the dashpot are placed in series. For a given brace stiffness, viscous damping coefficients and the distribution of the damping devices between stories are optimized by a procedure to reach a “target performance level”. The optimization is achieved by minimizing an “objective function” which rates the structural responses of the controlled system with the uncontrolled one. Generally, mean square responses of the inter-story drift, floor acceleration and base shear are among the structural response quantities considered for this procedure.KeywordsSeismic response control systemsSupplemental damping devicesSignals and systemsState-space approachNumerical optimizationGradient based optimization algorithm