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CONTENTS
Volume 19, Number 6, June 2017
 

Abstract
This paper introduces an approach to the realization of an ICT-based bridge remote monitoring system that enables real-time monitoring and controlled adjustments for unexpected heavy loads and also for damaging earthquakes or typhoons. In this paper, an integrated bridge remote monitoring system called the \"Intelligent Bridge\", which consists of a stand-alone monitoring system (SMS) and a web-based Internet monitoring system(IMS), was developed for not only bridge maintenance but also as an application for a para-stressing bridge system. To verify the possibility of controlling the actual structural performance of an \"Intelligent Bridge\", a model 2-span continuous cable-stayed bridge with adjustable cables was constructed. The experimental results demonstrate that the implemented monitoring system supplies detailed and accurate information about bridge behaviour for further evaluation and diagnosis, and it also opens up prospects for future application of a web-based remote system to actually adjust in-service bridges under field conditions.

Key Words
intelligent bridge; stand-alone monitoring system; internet monitoring system, structural performance; smart monitoring

Address
Ayaho Miyamoto: Graduate School of Science & Engineering, Yamaguchi University, 2-16-1, Tokiwadai, Ube, 755-8611, Japan
Minoru Motoshita: Kyowa Sekkei CO., LTD, 2-1-34, Ushitora, Ibaraki, Osaka, 567-0877, Japan

Abstract
In this work, free vibration analysis of size-dependent functionally graded (FG) nanoplates resting on two-parameter elastic foundation is investigated based on a novel nonlocal refined trigonometric shear deformation theory for the first time. This theory includes undetermined integral variables and contains only four unknowns, with is even less than the conventional first shear deformation theory (FSDT). Mori–Tanaka model is employed to describe gradually distribution of material properties along the plate thickness. Size-dependency of nanosize FG plate is captured via the nonlocal elasticity theory of Eringen. By implementing Hamilton\'s principle the equations of motion are obtained for a refined four-variable shear deformation plate theory and then solved analytically. To show the accuracy of the present theory, our research results in specific cases are compared with available results in the literature and a good agreement will be demonstrated. Finally, the influence of various parameters such as nonlocal parameter, power law indexes, elastic foundation parameters, aspect ratio, and the thickness ratio on the non-dimensional frequency of rectangular FG nanoscale plates are presented and discussed in detail.

Key Words
nonlocal elasticity theory; FG nanoplate; free vibration; refined theory; elastic foundation

Address
Abderrahmane Besseghier: Faculty of Technology, Department of Civil Engineering, Material and Hydrology Laboratory, University of Sidi Bel Abbes, Algeria
Mohammed Sid Ahmed Houari: Faculty of Technology, Department of Civil Engineering, Material and Hydrology Laboratory, University of Sidi Bel Abbes, Algeria;
Département of Civil Engineering, Université Mustapha Stambouli de Mascara, Mascara, Algeria
Abdelouahed Tounsi: Faculty of Technology, Department of Civil Engineering, Material and Hydrology Laboratory, University of Sidi Bel Abbes, Algeria;
Laboratoire de Modélisation et Simulation Multi-échelle, Département de Physique, Faculté des Sciences Exactes,
Département de Physique, Université de Sidi Bel Abbés, Algeria
S.R. Mahmoud4: Department of Mathematics, Faculty of Science, King Abdulaziz University, Saudi Arabia;
Mathematics Department, Faculty of Science, University of Sohag, Egypt



Abstract
This paper experimentally investigates the feasibility of harvesting vibration energy from whistles using piezoelectric materials. The end goal of this research is to generate sufficient power from the whistle to power a small radio transmitter to relay a basic signal – for example, a distress call. First, the paper discusses the current literature in energy harvesting from acoustic resonance. Next, the concept of an active whistle is presented. Next, results from energy harvesting experiments conducted on conventional and ultrasonic whistles undergoing human-actuation and actuation by a pressure-regulated air supply are presented. The maximum power density of the conventional whistle actuated by a human at 100 dB sound pressure level is 98.1 uw/cm3.

Key Words
piezoelectric materials; acoustics; vibration energy harvesting; whistle

Address
Rebecca Hattery: Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, Virginia, 23529, USA
Onur Bilgen: Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, Virginia, 23529, USA;
Department of Mechanical & Aerospace Engineering Rutgers, The State University of New Jersey 98 Brett Road, Piscataway, NJ 08854, USA


Abstract
In the fields of civil engineering and seismology, it is essential to detect and tracking the vibrations, and the fiber Bragg gratings (FBGs) are typically used as sensors to measure vibrations. Where, one of the most popular and detailed approaches to use FBGs as vibration sensors involves the use of cantilever beam designs, which adds a mass to measure low and moderate frequencies (from 20 Hz up to 1 kHz) with high sensitivities (greater than 10 pm/g). The design consists of a bending strain in the cantilever that is simultaneously transferred to the FBG, resulting in a shift in the wavelength that is proportional to the strain experienced by the cantilever. In this work, we present the experimental results of a vibration sensor design using a cantilever beam to generate an axial uniform strain in the FBG in-line with the vertical axis, which modifies the cantilever\'s natural frequency that allows the sensor to have a wide frequency broadband without losing sensitivity. This sensor achieved a sensitivity of about 339 pm/g and a natural frequency of 227.3 Hz. The presented design compared with the traditional cantilever beam-based FBG vibration sensors, has the advantages of a simple design for detection on vibration-sensitive structures and its physical parameters can be easily modified in order to satisfy the requirements of the desired vibration measurements.

Key Words
cantilever; fiber Bragg grating; frequency; sensitivity; vibration

Address
Miguel A. Casas-Ramos:Posgrado de Maestría y Doctorado en Ingeniería, Universidad Nacional Autónoma de México,
Av. Universidad 3000 Edificio T \"Bernardo Quintana Arrioja\", 04510, México
G.E. Sandoval-Romero: Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior S/N, A.P. 70-186, 04510, México



Abstract
The complexity of macro-fiber composite (MFC) materials increasing the difficulty in simulation and analysis of MFC integrated structures. To give an accurate prediction of MFC bonded smart structures for the simulation of shape and vibration control, the paper develops a linear electro-mechanically coupled static and dynamic finite element (FE) models based on the first-order shear deformation (FOSD) hypothesis. Two different types of MFCs are modeled and analyzed, namely MFC-d31 and MFC-d33, in which the former one is dominated by the d31 effect, while the latter one by the d33 effect. The present model is first applied to an MFC-d33 bonded composite plate, and then is used to analyze both active shape and vibration control for MFC-d31/-d33 bonded plate with various piezoelectric fiber orientations.

Key Words
macro-fiber composite; smart structures; dynamic analysis; piezoelectric; laminated structures

Address
Shun-Qi Zhang: School of Mechatronic Engineering and Automation, Shanghai University, Shanghai 200444, P.R. China;
State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, P.R. China
Min Chen: Department of Industrial Design, Xi\'an Jiaotong - Liverpool University, Suzhou 215123, P.R. China
Guo-Zhong Zhao: State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, P.R. China
Zhan-Xi Wang and Xian-Sheng Qin: School of Mechanical Engineering, Northwestern Polytechnical University, Xi\'an 710072, P.R. China
Rüdiger Schmidt: Institute of Structural Mechanics and Lightweight Design, RWTH Aachen University, Aachen 52062, Germany






Abstract
Pitched roof frames are widely used in construction of the industrial buildings, gyms, schools and colleges, fire stations, storages, hangars and many other low rise structures. The weight and shape of the gable frames with tapered members, as a familiar group of the pitched roof frames, are highly dependent on the properties of the member cross-sectional. In this work Enhanced Colliding Bodies Optimization (ECBO) is utilized for optimal design of three gable frames with tapered members. In order to optimize the frames, the design is performed using the AISC specifications for stress, displacement and stability constraints. The design constraints and weight of the gable frames are computed from the cross-section of members. These optimum weights are obtained using aforementioned optimization algorithms considering the cross-sections of the members and design constraints as optimization variables and constraints, respectively. A comparative study of the PSO and CBO with ECBO is also performed to illustrate the importance of the enhancement of the utilized optimization algorithm.

Key Words
gable frames; optimal design; meta-heuristic algorithms; tapered members; enhanced colliding bodies optimization algorithm

Address
Ali Kaveh, Vahid Reza Mahdavi and Mohammad Kamalinejad: Centre of Excellence for Fundamental Studies in Structural Engineering, Iran University of Science and Technology, Tehran, Iran

Abstract
The modal parameters of the deck of Runyang Suspension Bridge (RSB) as well as their relationships with wind and temperature are studied based on the data recorded by its Structural Health Monitoring System (SHMS). Firstly, frequency analysis on the vertical responses at the two sides of the deck is carried out to distinguish the vertical and torsional vibration modes. Then, the vertical, torsional and lateral modal parameters of the deck of RSB are identified using Hilbert-Huang Transform (HHT) and validated by the identified results before RSB was opened to traffic. On the basis of this, the modal frequencies and damping ratios of RSB during the whole process of Typhoon Masta are obtained. And the correlation analysis on the modal parameters and wind environmental factors is then conducted. Results show that the HHT can achieve an accurate modal identification of RSB and the damping ratios show an obvious decay trend as the frequencies increase. Besides, compared to frequencies, the damping ratios are more sensitive to the environmental factors, in particular, the wind speed. Further study on configuring the variation law of modal parameters related with environmental factors should be continued.

Key Words
modal parameter; suspension bridge; typhoon; wind; temperature; HHT

Address
Jian-Xiao Mao, Hao Wang, Zhi-Xiang Xun and Zhong-Qin Zou: Key Laboratory of C&PC Structures of Ministry of Education, Southeast University, No.2, Sipailou, Nanjing 210096, China


Abstract
In this paper the tuned mass-damper-inerter (TMDI) is considered for passive vibration control and energy harvesting in harmonically excited structures. The TMDI couples the classical tuned mass-damper (TMD) with a grounded inerter: a two-terminal linear device resisting the relative acceleration of its terminals by a constant of proportionality termed inertance. In this manner, the TMD is endowed with additional inertia, beyond the one offered by the attached mass, without any substantial increase to the overall weight. Closed-form analytical expressions for optimal TMDI parameters, stiffness and damping, given attached mass and inertance are derived by application of Den Hartog\'s tuning approach to suppress the response amplitude of force and base-acceleration excited single-degree-of-freedom structures. It is analytically shown that the TMDI is more effective from a same mass/weight TMD to suppress vibrations close to the natural frequency of the uncontrolled structure, while it is more robust to detuning effects. Moreover, it is shown that the mass amplification effect of the inerter achieves significant weight reduction for a target/predefined level of vibration suppression in a performance-based oriented design approach compared to the classical TMD. Lastly, the potential of using the TMDI for energy harvesting is explored by substituting the dissipative damper with an electromagnetic motor and assuming that the inertance can vary through the use of a flywheel-based inerter device. It is analytically shown that by reducing the inertance, treated as a mass/inertia-related design parameter not considered in conventional TMD-based energy harvesters, the available power for electric generation increases for fixed attached mass/weight, electromechanical damping, and stiffness properties.

Key Words
tuned mass damper; inerter; passive vibration control; energy harvesting; weight reduction; electromagnetic motor; optimal design

Address
Laurentiu Marian: AKT-II Ltd, 100 St John Street, EC1M 4EH, London, UK
Agathoklis Giaralis: Department of Civil Engineering, City, University of London, Northampton Square, EC1V 0HB, UK

Abstract
The complexity, enlargement and irregularity of structures and multi-directional dynamic loads acting on the structures can lead to unexpected structural behavior, such as torsion. Continuous torsion of the structure causes unexpected changes in the structure\'s stress distribution, reduces the performance of the structural members, and shortens the structure\'s lifespan. Therefore, a method of monitoring the torsional behavior is required to ensure structural safety. Structural torsion typically occurs accompanied by displacement, but no model has yet been developed to measure this type of structural response. This research proposes a model for measuring dynamic torsional response of structure accompanied by displacement and for identifying the torsional modal parameter using vision-based displacement measurement equipment, a motion capture system (MCS). In the present model, dynamic torsional responses including pure rotation and translation displacements are measured and used to calculate the torsional angle and displacements. To apply the proposed model, vibration tests for a shear-type structure were performed. The torsional responses were obtained from measured dynamic displacements. The torsional angle and displacements obtained by the proposed model using MCS were compared with the torsional response measured using laser displacement sensors (LDSs), which have been widely used for displacement measurement. In addition, torsional modal parameters were obtained using the dynamic torsional angle and displacements obtained from the tests.

Key Words
structural health monitoring; dynamic torsional displacement; motion capture system

Address
Hyo Seon Park, Doyoung Kim and Su Ah Lim: Department of Architectural Engineering, Yonsei University, Seoul 120-749, Republic of Korea
Byung Kwan Oh: Center for Structural Health Care Technology in Building, Yonsei University, Seoul 120-749, Republic of Korea

Abstract
In this paper, based on first-order shear deformation theory, the governing equations of motion for a sandwich curved beam including an elastic core and two piezo-magnetic face-sheets are presented. The curved beam model is resting on Pasternak\'s foundation and subjected to applied electric and magnetic potentials on the piezo-magnetic face-sheets and transverse loading. The five equations of motion are analytically solved and the bending and vibration results are obtained. The influence of important parameters of the model such as direct and shear parameters of foundation and applied electric and magnetic potentials are studied on the electro-mechanical responses of the problem. A comparison with literatures was performed to validate our formulation and results.

Key Words
three-layer curved beam; piezo-magnetic face-sheets; Pasternak\'s foundation; first-order shear deformation theory

Address
Mohammad Arefi: Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan 87317-51167, Iran
Ashraf M. Zenkour: Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia;
Department of Mathematics, Faculty of Science, Kafrelsheikh University, Kafrelsheikh 33516, Egypt


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