Effectiveness-robustness objectives in MTMD system design: An evolutionary optimal design methodology

Abstract

The main contribution pursued in this investigation is to propose a generic optimal methodology for designing multiple tuned mass damper (MTMD) systems to efficiently suppress the response of uncertain structures to harmonic excitations. This methodology comprises quantitative indexing of MTMD effectiveness and robustness as performance criteria, implementing a two-objective optimization and presenting solutions as optimal set of non-dominated designs. Within this three-step framework, utilization of a new index of robustness is proposed, advantages of exploiting multi-objective genetic algorithm are demonstrated, and the trade-off between effectiveness and robustness is visualized via Pareto-optimal solution fronts. A systematic stochastic procedure has been also proposed and carried out to provide validation and further insight into the robustness concept. Although a uniformly distributed MTMD (UMTMD) model is utilized for the illustration purpose, the formulation of the objective functions are generic, while at the same time, simple and convenient to modify according to any desired assumptions; hence, the proposed methodology is applicable to a broad range of problems. To demonstrate this versatility, this methodology is employed to optimize an irregular MTMD (IMTMD) without restrictive assumptions and to show its ability of handling design spaces with rather large dimensionality and complexity. Comparison of the results obtained from optimal effectiveness–robustness design of irregular and uniform MTMDs reveals the performance advantage of IMTMD over UMTMD design. Copyright © 2008 John Wiley & Sons, Ltd.