A hybrid metaheuristic method for optimization of active tuned mass dampers

Author(s):  
Aylin Ece Kayabekir ◽  
Sinan Melih Nigdeli ◽  
Gebrail Bekdaş

Tuned mass dampers (TMD) are one of the most reliable devices to control the vibration of the structure. The optimum mass ratio required for a single tuned mass damper (STMD) is evaluated corresponding to the fundamental natural frequency of the structure. The effect of STMD and Multiple tuned mass dampers (MTMD) on a G+20 storey structure are studied to demonstrate the damper’s effectiveness in seismic application. The location and number of tuned mass dampers are studied to give best structural performance in maximum reduction of seismic response for El Centro earthquake data. The analysis results from SAP 2000 software tool shows damper weighing 2.5% of the total weight of the structure effectively reduce the response of the structure. Study shows that introduction of 4-MTMD at top storey can effectively reduce the response by 10% more in comparison to single tuned mass damper. The use of MTMD of same mass ratio that of STMD is more effective in seismic response.


Author(s):  
Armin Morasaei ◽  
Aria Ghabussi ◽  
Soheila Aghlmand ◽  
Maziar Yazdani ◽  
Shahrizan Baharom ◽  
...  

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ha-Bang Ban ◽  
Phuong Khanh Nguyen

AbstractThe Asymmetric Distance-Constrained Vehicle Routing Problem (ADVRP) is NP-hard as it is a natural extension of the NP-hard Vehicle Routing Problem. In ADVRP problem, each customer is visited exactly once by a vehicle; every tour starts and ends at a depot; and the traveled distance by each vehicle is not allowed to exceed a predetermined limit. We propose a hybrid metaheuristic algorithm combining the Randomized Variable Neighborhood Search (RVNS) and the Tabu Search (TS) to solve the problem. The combination of multiple neighborhoods and tabu mechanism is used for their capacity to escape local optima while exploring the solution space. Furthermore, the intensification and diversification phases are also included to deliver optimized and diversified solutions. Extensive numerical experiments and comparisons with all the state-of-the-art algorithms show that the proposed method is highly competitive in terms of solution quality and computation time, providing new best solutions for a number of instances.


2021 ◽  
pp. 136943322110203
Author(s):  
Yanru Wu ◽  
Junxin Li ◽  
Qing Sun

This research aims to assess the pedestrian comfort and to control human-induced vibration of an arch tower cable-stayed bridge without backstays located in canyon. Dynamic simulations of human-induced vibration were carried out with a mode-by-mode approach, and the results indicated that a total of seven lateral and vertical modes of the bridge may suffer from excessive vibrations at the design crowd density. Based on the periodic walking force, the structure response under pedestrian loads was evaluated performing dynamic analyses with two Finite Element models of the footbridge. A single tuned mass damper (STMD) control system was developed for control of human-induced vibration, which consisted of four tuned mass dampers mounted on the mid-span of bridge to enhance damping ratios of lively modes. The results indicate that the maximum acceleration for the first-order lateral and second-order vertical vibration at the design crowd density exceed the associated threshold values referring to the comfort level 1 (CL1) Criteria. The critical pedestrian number of lateral dynamic instability estimated by the Dallard’s empirical formula is much smaller than the dynamic design pedestrian number; and the Dallard’s empirical formula is applicable to estimate the critical pedestrian number of lateral dynamic instability for this bridge by comparing with Pedroe Inês footbridge. The damping ratios for both the vertical and lateral modes increase appreciably after installing the tuned mass dampers and no evidence of large-amplitude vibrations has been observed, leading to the realization of satisfactory comfort levels, which can provide reference for vibration reduction design of this kind of bridge.


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