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Mass ratio factor for optimum tuned mass damper strategies
The TMD optimization expressions proposed in several academic papers were investigated for SDOF structures with different periods. These expressions are related to a constant mass ratio. Also, the mass ratio factor was investigated for these expressions. Under different earthquakes, the vibration reduction performance of the TMD varies according to period of the structure. In many structural periods, the increase of the mass ratio is not effective on solutions. According to these information; the mass ratio, period of the structure and the excitation must be taken into consideration during optimization. Also, different types of excitations can be used. Otherwise, the optimum solution may be valid for a specific excitation only. The simple expressions were also investigated for a MDOF structure. In addition to these optimization techniques, a metaheuristic algorithm called Harmony Search was proposed and compared with the other methods. The presented method is powerful on obtaining better solutions with adjustable ranges which provide more economical and physical parameters. The HS was conducted under six different earthquakes and the results were tested under benchmark earthquakes in order to show that the TMD parameters are true optimum. Four different cases of the range were investigated in order to take physical and economical conditions into account. In the all cases, the damping ratio converges to the bound of the range, because the optimization was conducted under different earthquakes. When using a single excitation, it may be possible to find a specific damping ratio. This value will be a local optimum corresponding to the excitation. Because of the uncertain nature of the earthquakes, this solution will not be feasible. The increase of the damping ratio is directly effective on the performance. In that case, the damping ratio can be thought as an unnecessary parameter to be optimized. But, the optimum mass and frequency ratios must be found corresponding to the damping ratio. By using the simple expressions, the damping ratio can be increased by using a big TMD mass. The usage of a big mass increases the weight of the structure. Thus, the earthquake loads may increase and the axial capacity of the columns may exceed the security conditions. Especially, the mass ratio must be kept in minimum levels for high rise buildings. In addition to that, the damping coefficient will increase with the increase of the mass and damping ratios. In that case, the cost of the TMD will boost. The HS approach for the optimization of TMD parameters is a feasible and adjustable method according to physical condition of structures.
Mass ratio factor for optimum tuned mass damper strategies
The TMD optimization expressions proposed in several academic papers were investigated for SDOF structures with different periods. These expressions are related to a constant mass ratio. Also, the mass ratio factor was investigated for these expressions. Under different earthquakes, the vibration reduction performance of the TMD varies according to period of the structure. In many structural periods, the increase of the mass ratio is not effective on solutions. According to these information; the mass ratio, period of the structure and the excitation must be taken into consideration during optimization. Also, different types of excitations can be used. Otherwise, the optimum solution may be valid for a specific excitation only. The simple expressions were also investigated for a MDOF structure. In addition to these optimization techniques, a metaheuristic algorithm called Harmony Search was proposed and compared with the other methods. The presented method is powerful on obtaining better solutions with adjustable ranges which provide more economical and physical parameters. The HS was conducted under six different earthquakes and the results were tested under benchmark earthquakes in order to show that the TMD parameters are true optimum. Four different cases of the range were investigated in order to take physical and economical conditions into account. In the all cases, the damping ratio converges to the bound of the range, because the optimization was conducted under different earthquakes. When using a single excitation, it may be possible to find a specific damping ratio. This value will be a local optimum corresponding to the excitation. Because of the uncertain nature of the earthquakes, this solution will not be feasible. The increase of the damping ratio is directly effective on the performance. In that case, the damping ratio can be thought as an unnecessary parameter to be optimized. But, the optimum mass and frequency ratios must be found corresponding to the damping ratio. By using the simple expressions, the damping ratio can be increased by using a big TMD mass. The usage of a big mass increases the weight of the structure. Thus, the earthquake loads may increase and the axial capacity of the columns may exceed the security conditions. Especially, the mass ratio must be kept in minimum levels for high rise buildings. In addition to that, the damping coefficient will increase with the increase of the mass and damping ratios. In that case, the cost of the TMD will boost. The HS approach for the optimization of TMD parameters is a feasible and adjustable method according to physical condition of structures.
Mass ratio factor for optimum tuned mass damper strategies
Bekdas, Gebrail (Autor:in) / Nigdeli, Sinan Melih (Autor:in)
International Journal of Mechanical Sciences ; 71 ; 68-84
2013
17 Seiten, 16 Bilder, 5 Tabellen, 44 Quellen
Aufsatz (Zeitschrift)
Englisch
| Europäisches Patentamt | 2019