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CONTENTS | |
Volume 16, Number 3, September 2015 |
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- An original device for train bogie energy harvesting: a real application scenario Francesco Amoroso, Rosario Pecora, Monica Ciminello and Antonio Concilio
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Abstract; Full Text (1256K) . | pages 383-399. | DOI: 10.12989/sss.2015.16.3.383 |
Abstract
Today, as railways increase their capacity and speeds, it is more important than ever to be completely aware of the state of vehicles fleet‟s condition to ensure the highest quality and safety standards, as well as being able to maintain the costs as low as possible. Operation of a modern, dynamic and efficient
railway demands a real time, accurate and reliable evaluation of the infrastructure assets, including signal
networks and diagnostic systems able to acquire functional parameters. In the conventional system,
measurement data are reliably collected using coaxial wires for communication between sensors and the
repository. As sensors grow in size, the cost of the monitoring system can grow. Recently, auto-powered
wireless sensor has been considered as an alternative tool for economical and accurate realization of
structural health monitoring system, being provided by the following essential features: on-board
micro-processor, sensing capability, wireless communication, auto-powered battery, and low cost. In this
work, an original harvester device is designed to supply wireless sensor system battery using train bogie
energy. Piezoelectric materials have in here considered due to their established ability to directly convert
applied strain energy into usable electric energy and their relatively simple modelling into an integrated
system. The mechanical and electrical properties of the system are studied according to the project
specifications. The numerical formulation is implemented with in-house code using commercial software
tool and then experimentally validated through a proof of concept setup using an excitation signal by a real
application scenario.
Key Words
wireless technology; energy harvesting; piezoelectric sensor
Address
Francesco Amoroso and Rosario Pecora, University of Napoli \"Federico II\", Industrial Engineering Department, Via Claudio, 21 -80125- Napoli, Italy
Monica Ciminello and Antonio Concilio, C.I.R.A.- Italian Aerospace Research Center, Smart Structures Lab, Via Maiorise 81043, Capua (CE), Italy
- A developed hybrid method for crack identification of beams Ali. R. Vosoughi
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Abstract; Full Text (1220K) . | pages 401-414. | DOI: 10.12989/sss.2015.16.3.401 |
Abstract
A developed hybrid method for crack identification of beams is presented. Based on the
Euler-Bernouli beam theory and concepts of fracture mechanics, governing equation of the cracked beams is
reformulated. Finite element (FE) method as a powerful numerical tool is used to discritize the equation in
space domain. After transferring the equations from time domain to frequency domain, frequencies and
mode shapes of the beam are obtained. Efficiency of the governed equation for free vibration analysis of the
beams is shown by comparing the results with those available in literature and via ANSYS software. The
used equation yields to move the influence of cracks from the stiffness matrix to the mass matrix. For crack
identification measured data are produced by applying random error to the calculated frequencies and mode
shapes. An objective function is prepared as root mean square error between measured and calculated data.
To minimize the function, hybrid genetic algorithms (GAs) and particle swarm optimization (PSO)
technique is introduced. Efficiency, Robustness, applicability and usefulness of the mixed optimization
numerical tool in conjunction with the finite element method for identification of cracks locations and depths
are shown via solving different examples.
Key Words
a hybrid inverse method; crack identification; reformulated governing equation; optimization;
hybrid GAs- PSO
Address
Ali. R. Vosoughi, Department of Civil and Environmental Engineering, School of Engineering Shiraz University, Shiraz, Iran
- A strain-based wire breakage identification algorithm for unbonded PT tendons A.B.M. Abdullah, Jennifer A. Rice and H.R. Hamilton
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Abstract; Full Text (2523K) . | pages 415-433. | DOI: 10.12989/sss.2015.16.3.415 |
Abstract
Tendon failures in bonded post-tensioned bridges over the last two decades have motivated
ongoing investigations on various aspects of unbonded tendons and their monitoring methods. Recent
research shows that change of strain distribution in anchor heads can be useful in detecting wire breakage in
unbonded construction. Based on this strain variation, this paper develops a damage detection model that
enables an automated tendon monitoring system to identify and locate wire breaks. The first part of this
paper presents an experimental program conducted to study the strain variation in anchor heads by
generating wire breaks using a mechanical device. The program comprised three sets of tests with fully
populated 19-strand anchor head and evaluated the levels of strain variation with number of wire breaks in
different strands. The sensitivity of strain variation with wire breaks in circumferential and radial directions
of anchor head in addition to the axial direction (parallel to the strand) were investigated and the measured
axial strains were found to be the most sensitive. The second part of the paper focuses on formulating the
wire breakage detection framework. A finite element model of the anchorage assembly was created to
demonstrate the algorithm as well as to investigate the asymmetric strain distribution observed in
experimental results. In addition, as almost inevitably encountered during tendon stressing, the effects of
differential wedge seating on the proposed model have been analyzed. A sensitivity analysis has been
performed at the end to assess the robustness of the model with random measurement errors.
Key Words
post-tensioned bridge; unbonded tendon; wire breakage; strain variation; post-tensioning
anchorage; multi-strand tendon; damage detection algorithm; automated tendon monitoring
Address
A.B.M. Abdullah, Jennifer A. Rice and H.R. Hamilton, Department of Civil and Coastal Engineering, University of Florida, Gainesville, FL 32611, USA
- Perturbation analysis for robust damage detection with application to multifunctional aircraft structures Rafik Hajrya and Nazih Mechbal
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Abstract; Full Text (1765K) . | pages 435-457. | DOI: 10.12989/sss.2015.16.3.435 |
Abstract
The most widely known form of multifunctional aircraft structure is smart structures for
structural health monitoring (SHM). The aim is to provide automated systems whose purposes are to identify
and to characterize possible damage within structures by using a network of actuators and sensors.
Unfortunately, environmental and operational variability render many of the proposed damage detection
methods difficult to successfully be applied. In this paper, an original robust damage detection approach
using output-only vibration data is proposed. It is based on independent component analysis and matrix
perturbation analysis, where an analytical threshold is proposed to get rid of statistical assumptions usually
performed in damage detection approach. The effectiveness of the proposed SHM method is demonstrated
numerically using finite element simulations and experimentally through a conformal load-bearing antenna
structure and composite plates instrumented with piezoelectric ceramic materials.
Key Words
structural health monitoring; robust damage detection; decision-making; analytical threshold;
matrix perturbation theory; range subspaces; independent component analysis; piezoelectric ceramic
material; composite structures; conformal load-bearing antenna structure; impact damages
Address
Rafik Hajrya and NazihMechbal, Arts et Métiers ParisTech (ENSAM), Process and Engineering in Mechanics and Materials Laboratory (PIMM)
CNRS-UMR 8006-151 Boulevard de l\'hôpital, 75013, Paris, France
- Design of a TMD solution to mitigate wind-induced local vibrations in an existing timber footbridge Daniele Bortoluzzi, Sara Casciati, Lorenzo Elia and Lucia Faravelli
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Abstract; Full Text (1473K) . | pages 459-478. | DOI: 10.12989/sss.2015.16.3.459 |
Abstract
The design of a passive control solution based on tuned mass dampers (TMD\'s) requires the estimation
of the actual masses involved in the undesired vibration. This task may result not so straightforward as expected
when the vibration resides in subsets of different structural components. This occurs, for instance, when the goal is to
damp out vibrations on stays. The theoretical aspects are first discussed and a design process is formulated. For sake
of exemplification, a multiple TMD\'s configurations is eventually conceived for an existing timber footbridge
located in the municipality of Trasaghis (North-Eastern Italy). The bridge span is 83 m and the deck width is 3.82
m.
Key Words
footbridges; passive control; tuned mass damper; vibration mitigation; wind load
Address
Daniele Bortoluzzi, Lorenzo Elia and Lucia Faravelli, Department of Civil Engineering and Architecture, University of Pavia, Via Ferrata 3, 27100 Pavia (PV), Italy
Sara Casciati, Department of Civil Engineering and Architecture, University of Catania at Siracusa, P.za Federico di Svevia, 96100 Siracusa, Italy
- A finite element analysis of a new design of a biomimetic shape memory alloy artificial muscle Moez Ben Jaber, Mohamed A. Trojette and Fehmi Najar
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Abstract; Full Text (2440K) . | pages 479-496. | DOI: 10.12989/sss.2015.16.3.479 |
Abstract
In this work, a novel artificial circular muscle based on shape memory alloy (S.M.A.) is
proposed. The design is inspired from the natural circular muscles found in certain organs of the human
body such as the small intestine. The heating of the prestrained SMA artificial muscle will induce its
contraction. In order to measure the mechanical work provided in this case, the muscle will be mounted on a
silicone rubber cylindrical tube prior to heating. After cooling, the reaction of the rubber tube will involve
the return of the muscle to its prestrained state. A finite element model of the new SMA artificial muscle was
built using the software \"ABAQUS\". The SMA thermomechanical behavior law was implemented using the
user subroutine \"UMAT\". The numerical results of the finite element analysis of the SMA muscle are
presented to shown that the proposed design is able to mimic the behavior of a natural circular muscle.
Key Words
shape memory alloy; bioinspiration; biomimetic; new design; artificial muscle; finite element
analysis
Address
Moez Ben Jaber, Systems and Applied Mechanics Research Laboratory, Tunisia Polytechnic School, University of Carthage, B.P. 743, La Marsa 2078, Tunisia ;National Engineering School of Tunis, University of El-Manar, BP 37, Le Belvédère 1002 Tunis, Tunisia
Mohamed A. Trojette, College of Sciences and Techniques of Tunis, University of Tunis, BP 56, 5 Avenue Taha Hussein, Bâb
Manara, Tunis, Tunisia
Fehmi Najar, Systems and Applied Mechanics Research Laboratory, Tunisia Polytechnic School, University of Carthage, B.P. 743, La Marsa 2078, Tunisia
- Fuzzy modelling approach for shear strength prediction of RC deep beams Mohammad Mohammadhassani, Aidi MD. Saleh, M Suhatril and M. Safa
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Abstract; Full Text (1797K) . | pages 497-519. | DOI: 10.12989/sss.2015.16.3.497 |
Abstract
This study discusses the use of Adaptive-Network-Based-Fuzzy-Inference-System (ANFIS) in
predicting the shear strength of reinforced-concrete deep beams. 139 experimental data have been collected
from renowned publications on simply supported high strength concrete deep beams. The results show that
the ANFIS has strong potential as a feasible tool for predicting the shear strength of deep beams within the
range of the considered input parameters. ANFIS‟s results are highly accurate, precise and therefore, more
satisfactory. Based on the Sensitivity analysis, the shear span to depth ratio (a/d) and concrete cylinder
strength (f) have major influence on the shear strength prediction of deep beams. The parametric study
confirms the increase in shear strength of deep beams with an equal increase in the concrete strength and
decrease in the shear span to-depth-ratio.
Key Words
deep beams; ultimate shear strength; ANFIS; LR
Address
Mohammad Mohammadhassani, Department of Structural Engineering, University of Malaya, Malaysia
Aidi MD. Saleh, Malaysian public work department, Ledang, Tangkak, 84900 Johor, Malaysia
M Suhatril and M. Safa, Department of Civil Engineering, University of Malaya, Malaysia
- Dynamic and static structural displacement measurement using backscattering DC coupled radar Shanyue Guan, Jennifer A. Rice, Changzhi Li, Yiran Li and Guochao Wang
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Abstract; Full Text (1497K) . | pages 521-535. | DOI: 10.12989/sss.2015.16.3.521 |
Abstract
Vibration-based monitoring is one approach used to perform structural condition assessment.
By measuring structural response, such as displacement, dynamic characteristics of a structure may be
estimated. Often, the primary dynamic responses in civil structures are below 5 Hz, making accurate low
frequency measurement critical for successful dynamic characterization. In addition, static deflection
measurements are useful for structural capacity and load rating assessments. This paper presents a DC
coupled continuous wave radar to accurately detect both dynamic and static displacement. This low-cost
radar sensor provides displacement measurements within a compact, wireless unit appropriate for a range of
structural monitoring applications. The hardware components and operating mechanism of the radar are
introduced and a series of laboratory experiments are presented to assess the performance characteristics of
the radar. The laboratory and field experiments investigate the effect of factors such as target distance,
motion amplitude, and motion frequency on the radar\'s measurement accuracy. The results demonstrate that
the radar is capable of both static and dynamic displacement measurements with sub-millimeter accuracy,
making it a promising technology for structural health monitoring.
Key Words
DC coupled radar; dynamic displacement; static deflection; moving load test
Address
Shanyue Guan and Jennifer A. Rice, Engineering School of Sustainable Infrastructure and Environment, University of Florida, Gainesville, FL, USA 32611
Changzhi Li, Yiran Li and Guochao Wang,Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas, USA 79409
- Pyroeffects on magneto-electro-elastic sensor bonded on mild steel cylindrical shell P. Kondaiah, K. Shankar and N. Ganesan
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Abstract; Full Text (1529K) . | pages 537-554. | DOI: 10.12989/sss.2015.16.3.537 |
Abstract
Magneto-electro-elastic (MEE) materials under thermal environment exhibits pyroelectric and
pyromagnetic coefficients resulting in pyroeffects such as pyroelectric and pyromagnetic. The pyroeffects on
the behavior of multiphase MEE sensor bonded on top surface of a mild steel cylindrical shell under thermal
environment is presented in this paper. The study aims to investigate how samples having different volume
fractions of the multiphase MEE sensor behave due to pyroeffects using semi-analytical finite element
method. This is studied at an optimal location on a mild steel cylindrical shell, where the maximum electric
and magnetic potentials are induced due to these pyroeffects under different boundary conditions. It is
assumed that sensor and shell is perfectively bonded to each other. The maximum pyroeffects on electric and
magnetic potentials are observed when volume fraction is vf = 0.2. Additionally, the boundary conditions
significantly influence the pyroeffects on electric and magnetic potentials.
Key Words
pyroelectric; pyromagnetic; magneto-electro-elastic sensor; cylindrical shell; semi-analytical
finite element
Address
P. Kondaiah, Department of Mechanical Engineering, School of Engineering & Technology, Mahindra É cole Centrale, Hyderabad, Andhra Pradesh 500043, India
K. Shankar and N. Ganesan, Machine Design Section, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
- A SMA-based morphing flap: conceptual and advanced design Salvatore Ameduri,Antonio Concilio and Rosario Pecora
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Abstract; Full Text (1880K) . | pages 555-577. | DOI: 10.12989/sss.2015.16.3.555 |
Abstract
In the work at hand, the development of a morphing flap, actuated through shape memory alloy
load bearing elements, is described. Moving from aerodynamic specifications, prescribing the morphed
shape enhancing the aerodynamic efficiency of the flap, a suitable actuation architecture was identified, able
to affect the curvature. Each rib of the flap was split into three elastic elements, namely \"cells\", connected
each others in serial way and providing the bending stiffness to the structure. The edges of each cell are
linked to SMA elements, whose contraction induces rotation onto the cell itself with an increase of the local
curvature of the flap airfoil. The cells are made of two metallic plates crossing each others to form a
characteristic \"X\" configuration; a good flexibility and an acceptable stress concentration level was obtained
non connecting the plates onto the crossing zone. After identifying the main design parameters of the
structure (i.e. plates relative angle, thickness and depth, SMA length, cross section and connections to the
cell) an optimization was performed, with the scope of enhancing the achievable rotation of the cell, its
ability in absorbing the external aerodynamic loads and, at the same time, containing the stress level and the
weight. The conceptual scheme of the architecture was then reinterpreted in view of a practical realization of
the prototype. Implementation issues (SMA - cells connection and cells relative rotation to compensate the
impressed inflection assuring the SMA pre-load) were considered. Through a detailed FE model the
prototype morphing performance were investigated in presence of the most severe load conditions.
Key Words
shape memory alloys; smart structures; morphing; flap
Address
Salvatore Ameduri and Antonio Concilio, Smart Structures and Materials Lab., Centro Italiano Ricerche Aerospaziali, Via Maiorise, 81043, Capua (CE), Italy
Rosario Pecora, Department of Aerospace Engineering, Università degli Studi di Napoli \"Federico II\", Via Claudio, 21, 80125, Napoli, Italy