# Adaptive Harmony Search for Tuned Liquid Damper Optimization under Seismic Excitation
## 1 Introduction
This algorithm, which aims to achieve the best harmony, can search for a favorite harmony in the memory bank during the search process, create a melody similar to this harmony, or improvise for optimum harmony by creating an unheard harmony from scratch [14]. The effect of the harmony search algorithm on design optimization has been supported by various studies [15; 16; 17; 18; 19; 20; 21]. In recent years, it has become a preferred algorithm in damper optimization by being applied in the design of mass and liquid dampers [22; 23; 2]. The harmony search algorithm includes design factors such as memory consideration ratio (HMCR) and fret width (FW). The correct selection of these algorithm-specific factors is of great importance for the efficiency of the optimization. It is possible to start a progressively decreasing search process within a certain range by giving initial values to the HMCR and FW parameters. This process has developed the adaptive harmony search algorithm (AHS). Optimizing the design factors makes the algorithm more efficient. Thanks to the adjustments made to the parameters of the classical HS algorithm, positive results were obtained in the design optimization of engineering structures. [PERSON] and [PERSON] used the improved harmony search algorithm (IHS), produced by adjusting the fret width (FW) and bandwidth (BW) of the HS algorithm, in the optimization of mass dampers used in the design of a water intake tower. IHS provided optimum frequency, damping, and mass ratio calculations, and obtained better results than the optimization method of [PERSON], [PERSON], [PERSON], et al., [PERSON], and [PERSON] [24; 25; 26; 27; 28]. In engineering, optimization of tuned mass dampers, steel-framed structures, nonlinear plane strain systems, reinforced concrete shear walls, etc., are studied with the optimization of AHS and its hybrids. The classical HS algorithm, with adaptation of algorithm parameters, showed better results than some metaheuristic algorithms [29; 30; 31; 32; 33]. Since the HS algorithm has been successfully applied to many structural engineering problems, including control applications, it has been recently proven that the performance of the algorithm can be increased by improving the algorithm with adaptive methods; adaptive HS has been applied in TLDs, which are a different passive structural control problem. The best knowledge of this algorithm is another reason for choosing this algorithm. In this study, by adding a cylindrical TLD to single and ten-story building models, the damper parameters were optimized with the HS algorithm to obtain the minimum displacement under seismic excitation. A TLD based on water was applied to both single-story structures with a natural period of 0.5 s, 1 s, and 1.5 s, and a ten-story structure. Optimization was obtained by applying various seismic excitations using a simulation prepared on MATLAB [34; 35]. The classical HS algorithm parameters were adjusted, the optimization process was repeated with the AHS algorithm, and the results of the two algorithms were analyzed for critical earthquake recording. In light of the results obtained, the classical HS and adapted AHS algorithms were compared. For a single case study, two other modified HS algorithms were also compared to show the efficiency of the AHS.