Optimal Pendulum Tuned Mass Damper Design Applied to High Towers Using Genetic Algorithms: Two-DOF Modeling

2019 ◽  
Vol 19 (10) ◽  
pp. 1950125 ◽  
Author(s):  
Gino B. Colherinhas ◽  
Marcus V. G. de Morais ◽  
Maura A. M. Shzu ◽  
Suzana M. Avila
Keyword(s):  
Passive Control ◽  
Fitness Function ◽  
Low Cost ◽  
Maximum Amplitude ◽  
Time History ◽  
Random Force ◽  
Flexural Stiffness ◽  
Optimal Parameters ◽  
Mass Ratio ◽  
Damper Design

High and slender towers may experience excessive vibrations caused by both wind and seismic loads. To avoid excessive vibrations in towers, tuned mass dampers (TMDs) are often used as passive control devices due to their low cost. The TMDs can absorb part of the energy of vibration transmitted from the main structure. These devices need to be finely tuned in order to work as efficient dampers; otherwise, they can adversely amplify structural vibrations. This paper presents the optimal parameters of a pendulum TMD (PTMD) to control the vibrations of slender towers subjected to an external random force. The tower is modeled as a single-degree-of-freedom (SDOF) mass–spring system via an assumed-mode procedure with a pendulum attached. A genetic algorithm (GA) toolbox developed by the authors is used to find the optimal parameters of the PTMD, such as the support flexural stiffness/damping, the mass ratio and the pendulum length. The chosen fitness function searches for a minimization of the maximum frequency peaks. The results are compared with a sensibility map that contains the information of the maximum amplitude as a function of the pendulum length and the mass ratio between the pendulum and the tower. The optimal parameters can be expressed as a power-law function of the supporting flexural stiffness. In addition, a parametric analysis and a time-history verification are performed for several combinations of mass ratio and pendulum length.

scholarly journals Seismic Performance Analysis of a Connected Multitower Structure with FPS and Viscous Damper

2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Xiaohan Wu ◽  
Jun Wang ◽  
Jiangyong Zhou
Keyword(s):  
Seismic Behavior ◽  
Passive Control ◽  
Time History ◽  
Tuned Mass Damper ◽  
Seismic Excitations ◽  
History Analysis ◽  
Mass Damper ◽  
Tower Structure ◽  
Design Requirements ◽  
Friction Pendulum

A high four-tower structure is interconnected with a long sky corridor bridge on the top floor. To reduce the earthquake responses and member forces of the towers and sky corridor bridge, a passive control strategy with a friction pendulum tuned mass damper (FPTMD) was adopted. The sky corridor bridge was as the mass of FPTMD. The connection between the towers and the sky corridor bridge was designed as flexible links, where friction pendulum bearings (FPBs) and viscous dampers were installed. Elastoplastic time-history analysis was conducted by using Perform-3D model to look into its seismic behavior under intensive seismic excitation. The optimal design of the FPTMD with varying friction coefficients and radius of friction pendulum bearing (FPB) under seismic excitations was carried out, and the seismic behavior of the structure was also investigated at the same time.Results show that, for this four-tower connected structure, the friction pendulum tuned mass damper (FPTMD) has very well effect on seismic reduction. The structure can meet the seismic resistance design requirements.

Determination of Ultrasonic Welding Optimal Parameters for Thermoplastic Material of Manufacturing Products

2013 ◽  
Vol 64 (1) ◽  
Author(s):  
Rashiqah Rashli ◽  
Elmi Abu Bakar ◽  
Shahrul Kamaruddin
Keyword(s):  
Electronic Device ◽  
Low Cost ◽  
Near Field ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Field Configuration ◽  
Welding Parameters ◽  
Optimal Parameters ◽  
Thermoplastic Material

Ultrasonic welding had been widely used in various manufacturing industries such as aviation, medical, electronic device and many more. It offers a continued safe operation, faster and also low cost as it able to join weld part less than one second and also simple to maintain the tooling devices. Though ultrasonic welding brings a lot of advantages in assembly especially in thermoplastic material of manufacturing product, it also has a dominant problem to be deal with. The problem in ultrasonic welding is poor weld quality due to improper selection of ultrasonic welding parameters especially in near field configuration. Thus, an optimal combination of parameters is crucial in order to produce good quality weld assembly for this configuration. In this paper, ultrasonic welding process, ultrasonic weld joint defects and determination of optimal parameters for thermoplastic material had been discussed thoroughly. 

Moth Flame Optimization Algorithm Range-Based for Node Localization Challenge in Decentralized Wireless Sensor Network

2019 ◽  
Vol 10 (1) ◽  
pp. 82-109 ◽  
Author(s):  
Mihoubi Miloud ◽  
Rahmoun Abdellatif ◽  
Pascal Lorenz
Keyword(s):  
Swarm Intelligence ◽  
Optimization Algorithm ◽  
Dimensional Space ◽  
Fitness Function ◽  
Low Cost ◽  
Bat Algorithm ◽  
Wireless Sensor ◽  
Flower Pollination Algorithm ◽  
Node Localization ◽  
Moth Flame Optimization Algorithm

Recently developments in wireless sensor networks (WSNs) have raised numerous challenges, node localization is one of these issues. The main goal in of node localization is to find accurate position of sensors with low cost. Moreover, very few works in the literature addressed this issue. Recent approaches for localization issues rely on swarm intelligence techniques for optimization in a multi-dimensional space. In this article, we propose an algorithm for node localization, namely Moth Flame Optimization Algorithm (MFOA). Nodes are located using Euclidean distance, thus set as a fitness function in the optimization algorithm. Deploying this algorithm on a large WSN with hundreds of sensors shows pretty good performance in terms of node localization. Computer simulations show that MFOA converge rapidly to an optimal node position. Moreover, compared to other swarm intelligence techniques such as Bat algorithm (BAT), particle swarm optimization (PSO), Differential Evolution (DE) and Flower Pollination Algorithm (FPA), MFOA is shown to perform much better in node localization task.

scholarly journals Optimization of flat-oval pipes and perspectives of their application in beam structures

2018 ◽  
Vol 251 ◽  
pp. 03016
Author(s):  
Alexander Marutyan ◽  
Tamazi Kobaliya ◽  
Evgeny Galdin
Keyword(s):  
Cross Sections ◽  
Bending Strength ◽  
Low Cost ◽  
Design Parameters ◽  
Technical Solution ◽  
Optimal Parameters ◽  
Resistance Moment ◽  
Thin Walled ◽  
Lower Height ◽  
Oval Shape

A new technical solution for re-profiling round tubes into flat-oval ones with a ratio of 1 / 3,064 is presented, which increases their bending strength. The calculation of the optimal parameters of thin-walled sections of the flat-oval shape is given by an approximate method, the correctness of which is confirmed by testing from the standard profiles used. This calculation is repeated with respect to thin-walled sections of the oval shape. The whole diagram of changes in the design parameters of flat-oval and oval pipes is presented in the transformation of their cross-sections from vertical configurations to horizontal ones, including the transition through the outline of a circular shape. The comparative analysis of optimized cross sections of flat oval, oval and round tubes is carried out taking into account the elastic and elastic-plastic deformations of the structural material, where the length of the midline of the thin-walled section is taken as the dividing line between these deformations. The choice is substantiated in favour of flat-oval profile pipes due to their simpler shape including faces of constant curvature (flat and semi-circular), relatively low cost, lower height, greater compactness, higher resistance moment.

scholarly journals Adaptive Scatter Search to Solve the Minimum Connected Dominating Set Problem for Efficient Management of Wireless Networks

Algorithms ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 35 ◽  
Author(s):  
Abdel-Rahman Hedar ◽  
Shada N. Abdulaziz ◽  
Adel A. Sewisy ◽  
Gamal A. El-Sayed
Keyword(s):  
Fitness Function ◽  
Low Cost ◽  
Dominating Set ◽  
Scatter Search ◽  
Optimal Solution ◽  
Connected Dominating Set ◽  
Solution Quality ◽  
Efficient Management ◽  
Minimum Connected Dominating Set ◽  
Test Graph

An efficient routing using a virtual backbone (VB) network is one of the most significant improvements in the wireless sensor network (WSN). One promising method for selecting this subset of network nodes is by finding the minimum connected dominating set (MCDS), where the searching space for finding a route is restricted to nodes in this MCDS. Thus, finding MCDS in a WSN provides a flexible low-cost solution for the problem of event monitoring, particularly in places with limited or dangerous access to humans as is the case for most WSN deployments. In this paper, we proposed an adaptive scatter search (ASS-MCDS) algorithm that finds the near-optimal solution to this problem. The proposed method invokes a composite fitness function that aims to maximize the solution coverness and connectivity and minimize its cardinality. Moreover, the ASS-MCDS methods modified the scatter search framework through new local search and solution update procedures that maintain the search objectives. We tested the performance of our proposed algorithm using different benchmark-test-graph sets available in the literature. Experiments results show that our proposed algorithm gave good results in terms of solution quality.

Friction-Type Seismic Isolation Device of Steel Pile Foundation in Shaking Table Tests and its Numerical Simulations

2016 ◽  
Vol 845 ◽  
pp. 233-239
Author(s):  
Buntara Sthenly Gan ◽  
Susumu Nakamura ◽  
Noriaki Sento ◽  
Kosuke Ito
Keyword(s):  
Numerical Simulations ◽  
Pile Foundation ◽  
Seismic Isolation ◽  
Low Cost ◽  
Time History ◽  
Shaking Table ◽  
Steel Sphere ◽  
Pile Cap ◽  
Isolation Device ◽  
Nonlinear Time History

Pile foundation equipped with a low-cost frictional type seismic isolation device is investigated. The frictional mechanism results from a contact between two surfaces of a half steel sphere mounted on the pile cap and the corresponding inner steel sphere embedded in the footing of upper structure. To verify the mechanical behaviors of the pile with frictional type seismic isolation device, tests, and its numerical simulations have been performed. The rotational friction device is found to be very effective in releasing the internal energy transferred from the pile foundation to the upper structure. The behavior of the friction-type device was studied by modeling using the nonlinear time history dynamic analysis. It was observed that the responses of the structures with devices can be approximated by using springs and dampers model.

Passive Control of Seismic Response of Piping Systems

2005 ◽  
Vol 128 (3) ◽  
pp. 364-369 ◽  
Author(s):  
Y. M. Parulekar ◽  
G. R. Reddy ◽  
K. K. Vaze ◽  
K. Muthumani
Keyword(s):  
Passive Control ◽  
Response Spectrum ◽  
Time History ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Equivalent Linearization ◽  
Piping System ◽  
Equivalent Damping ◽  
History Analysis ◽  
Piping Systems

Passive energy dissipating devices, such as elastoplastic dampers (EPDs) can be used for eliminating snubbers and reducing the response of piping systems subjected to seismic loads. Cantilever and three-dimensional piping systems were tested with and without EPD on shaker table. Using a finite element model of the piping systems, linear and nonlinear time-history analysis is carried out using Newmark’s time integration technique. Equivalent linearization technique, such as Caughey method, is used to evaluate the equivalent damping of the piping systems supported on elastoplastic damper. An iterative response spectrum method is used for evaluating response of the piping system using this equivalent damping. The analytical maximum response displacement obtained at the elastoplastic damper support for the two piping systems is compared with experimental values and time history analysis values. It has been concluded that the iterative response spectrum technique using Caughey equivalent damping is simple and results in reasonably acceptable response of the piping systems supported on EPD.

Study on Parameters Optimization of Ceramic Machining Process

2011 ◽  
Vol 418-420 ◽  
pp. 1338-1341
Author(s):  
Qiang Wang ◽  
Ying Ying Zeng ◽  
Xu Guang Min
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Cutting Speed ◽  
Tool Material ◽  
Parameters Optimization ◽  
Machining Process ◽  
Impact Factors ◽  
Surface Model ◽  
Optimal Parameters ◽  
Ceramic Machining

The response surface model is established through application of surface response method, then the main impact factors of ceramic machining are determined, and the process parameters are optimized. The mechanical machining technology of ceramic materials is analyzed, and the corresponding optimal parameters are proposed by cutting tool material, rake angle, clearance angle and edge angle, and three cutting elements as cutting speed, cutting depth and feed. Accord to the optimal parameters, high efficiency, good quality and low cost results can be achieved to machine ceramic parts.

The Passive Control Seismic Strengthen about RC Frame Infilled Wall Structure

2013 ◽  
Vol 405-408 ◽  
pp. 1056-1062
Author(s):  
Qing Li Meng ◽  
Jun Chen ◽  
Chun Yu Chu
Keyword(s):  
Seismic Performance ◽  
Passive Control ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Wall Structure ◽  
Rc Frame ◽  
Reinforced Concrete Frame ◽  
Direction Parallel ◽  
Plane Direction ◽  
Performance Target

In this paper, a four-storey reinforced concrete frame infilled wall structure does not meet the seismic perform target, based on the seismic behavior target of both frame and infilled wall, to carry out the study on the passive control seismic strengthen of RC infilled wall structure with attached dampers. First, two kinds of passive control strengthen schemes were put forward. Scheme 1: Dampers were installed in the in-plane direction parallel with all 1-storey infilled walls; Scheme 2: Dampers were installed in the in-plane direction parallel with all 1-storey and 2-storey infilled walls. Then to establish the two types of passive control seismic strengthen model in OpenSees, carry out the rare earthquake nonlinear time-history analysis under El Centro, Parkfield and San Fenando ground motions. Finally, in accordance with the seismic performance target quantization index of RC Frame infilled wall structure used as hospital, i.e. considering storey drift ratio limit and infilled wall damage, judge the scheme 2 can meets the seismic performance target.

Optimum Vibration Absorbers for Linear Damped Systems

1981 ◽  
Vol 103 (4) ◽  
pp. 908-913 ◽  
Author(s):  
S. E. Randall ◽  
D. M. Halsted ◽  
D. L. Taylor
Keyword(s):  
Damping Ratio ◽  
Maximum Amplitude ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Mass Ratio ◽  
Linear Vibration ◽  
Optimal Linear ◽  
Damped Systems ◽  
Independent Parameters ◽  
Qualitative Discussion

This paper presents computational graphs that determine the optimal linear vibration absorber for linear damped primary systems. Considered as independent parameters are the main system damping ratio and the mass ratio examined over the range 0 to 0.50 and 0.01 to 0.40, respectively. The remaining nondimensional parameters were optimized using numerical methods based on minimum-maximum amplitude criteria. With independent parameters specified the computational graphs can be used to find the response amplitudes as well as the optimal absorber characteristics. This procedure is illustrated in a design example. A qualitative discussion of the sensitivity to parameter errors is presented.

Sign in / Sign up

Export Citation Format

Share Document