A refined shear lag model for adhesively bonded piezo-impedance transducers:
01 Jan 2013-Journal of Intelligent Material Systems and Structures (SAGE Publications)-Vol. 24, Iss: 1, pp 33-48
TL;DR: In this paper, a new refined analytical model for inclusion of the shear lag effect in modelling of adhesively bonded piezoelectric ceramic (lead zirconate titanate) patches for consideration in the electromechanical impedance technique is presented.
Abstract: The performance (sensing/actuating) of a piezotransducer highly depends upon the ability of the bond layer to transfer the stress and strain (through shear lag mechanism) between the transducer and the structure. Therefore, the coupled electromechanical response of the piezotransducer should consider the effect of dynamic behaviour, geometry and composition of the adhesive layer used to bond the transducer patch on the structure. This article presents a new refined analytical model for inclusion of the shear lag effect in modelling of adhesively bonded piezoelectric ceramic (lead zirconate titanate) patches for consideration in the electromechanical impedance technique. The previous models neglected the inertial term in shear lag formulations for simplicity. The present refined model, on the other hand, considers the inertial and the shear lag effects simultaneously, and is therefore more rigorous and complete. In this article, the formulations are first derived for one-dimensional case, and then extended...
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TL;DR: In this paper, a review of recent research and development in the field of damage detection for wind turbine blades is presented, including fiber optic and piezoelectric sensors, and four promising damage detection methods, namely, transmittance function, wave propagation, impedance and vibration based methods.
Abstract: Wind energy is one of the most important renewable energy sources and many countries are predicted to increase wind energy portion of their whole national energy supply to about twenty percent in the next decade. One potential obstacle in the use of wind turbines to harvest wind energy is the maintenance of the wind turbine blades. The blades are a crucial and costly part of a wind turbine and over their service life can suffer from factors such as material degradation and fatigue, which can limit their effectiveness and safety. Thus, the ability to detect damage in wind turbine blades is of great significance for planning maintenance and continued operation of the wind turbine. This paper presents a review of recent research and development in the field of damage detection for wind turbine blades. Specifically, this paper reviews frequently employed sensors including fiber optic and piezoelectric sensors, and four promising damage detection methods, namely, transmittance function, wave propagation, impedance and vibration based methods. As a note towards the future development trend for wind turbine sensing systems, the necessity for wireless sensing and energy harvesting is briefly presented. Finally, existing problems and promising research efforts for online damage detection of turbine blades are discussed.
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TL;DR: In this paper, the chloride-induced breakdown of the passive film formed in the reinforced concrete structures is most frequently the result of the chloride induced breakdown of passive films formed in reinforced concrete.
Abstract: Rebar corrosion has become a very common cause of degradation in the reinforced concrete structures. It is most frequently the result of the chloride-induced breakdown of the passive film formed in...
66 citations
Cites background from "A refined shear lag model for adhes..."
...…of a piezo transducer highly depends upon the ability of the bond layer to transfer the stress and strain (through shear lag mechanism) between the transducer and the structure (Bhalla and Moharana, 2013), embedded sensors are likely to exhibit better and more consistent performance....
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...performance (sensing/actuation) of a piezo transducer highly depends upon the ability of the bond layer to transfer the stress and strain (through shear lag mechanism) between the transducer and the structure (Bhalla and Moharana, 2013), embedded sensors are likely to exhibit better and more consistent performance....
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TL;DR: In this article, the authors focused on the development of the method for assessment of the adhesive bonds in carbon fiber-reinforced polymer (CFRP) samples and evaluated the performance of adhesive bonds.
Abstract: The joints between structural elements should ensure safe usage of the structure. One of the joining method is based on adhesive bonding. However, adhesive bonding has not replaced riveting yet. Rivets are still present even in newest composite aircraft AIRBUS 350. The reliability of the adhesive bonding limits the use of adhesive bonding for primary aircraft structures and there is a search for new non-destructive testing tools allowing to (1) assessment of the surfaces before bonding and (2) assessment of the adhesive bond. The performance of adhesive bonds depends on the physico-chemical properties of the bonded surfaces. The contamination leading to weak bonds may have various origin and be caused by contamination (moisture, release agent, hydraulic fluid and fuel) or poor curing of adhesive. In this work, the research is focused on the development of the method for assessment of the adhesive bonds. Bonded carbon fibre–reinforced polymer samples were considered. Electromechanical impedance technique w...
62 citations
Cites methods from "A refined shear lag model for adhes..."
...One also should not forget that the sensors for EMI technique are bonded to the structure and the bonding itself has an influence on the response.(11,12)...
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TL;DR: In this paper, a series of parametric studies using the 3D coupled field finite element method (FEM) on all properties of materials involved in the lead zirconate titanate (PZT) structure interaction of the EMI technique, to investigate their effect on the admittance signatures acquired.
Abstract: The application of smart materials in various fields of engineering has recently become increasingly popular. For instance, the high frequency based electromechanical impedance (EMI) technique employing smart piezoelectric materials is found to be versatile in structural health monitoring (SHM). Thus far, considerable efforts have been made to study and improve the technique. Various theoretical models of the EMI technique have been proposed in an attempt to better understand its behavior. So far, the three-dimensional (3D) coupled field finite element (FE) model has proved to be the most accurate. However, large discrepancies between the results of the FE model and experimental tests, especially in terms of the slope and magnitude of the admittance signatures, continue to exist and are yet to be resolved. This paper presents a series of parametric studies using the 3D coupled field finite element method (FEM) on all properties of materials involved in the lead zirconate titanate (PZT) structure interaction of the EMI technique, to investigate their effect on the admittance signatures acquired. FE model updating is then performed by adjusting the parameters to match the experimental results. One of the main reasons for the lower accuracy, especially in terms of magnitude and slope, of previous FE models is the difficulty in determining the damping related coefficients and the stiffness of the bonding layer. In this study, using the hysteretic damping model in place of Rayleigh damping, which is used by most researchers in this field, and updated bonding stiffness, an improved and more accurate FE model is achieved. The results of this paper are expected to be useful for future study of the subject area in terms of research and application, such as modeling, design and optimization.
60 citations
TL;DR: In this paper, the authors investigated the relationship between forms of material damage, visual indication of damage, mechanical compliance of the material and resonant mode in the electro-mechanical impedance measurement of a PZT bonded to a concrete substrate.
60 citations
References
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TL;DR: In this paper, a scaling analysis is performed to demonstrate that the effectiveness of actuators is independent of the size of the structure and evaluate various piezoelectric materials based on their effectiveness in transmitting strain to the substructure.
Abstract: This work presents the analytic and experimental development of piezoelectric actuators as elements of intelligent structures, i.e., structures with highly distributed actuators, sensors, and processing networks. Static and dynamic analytic models are derived for segmented piezoelectric actuators that are either bonded to an elastic substructure or embedded in a laminated composite. These models lead to the ability to predict, a priori, the response of the structural member to a command voltage applied to the piezoelectric and give guidance as to the optimal location for actuator placement. A scaling analysis is performed to demonstrate that the effectiveness of piezoelectric actuators is independent of the size of the structure and to evaluate various piezoelectric materials based on their effectiveness in transmitting strain to the substructure. Three test specimens of cantilevered beams were constructed: an aluminum beam with surface-bonded actuators, a glass/epoxy beam with embedded actuators, and a graphite/epoxy beam with embedded actuators. The actuators were used to excite steady-state resonant vibrations in the cantilevered beams. The response of the specimens compared well with those predicted by the analytic models. Static tensile tests performed on glass/epoxy laminates indicated that the embedded actuator reduced the ultimate strength of the laminate by 20%, while not significantly affecting the global elastic modulus of the specimen.
2,719 citations
TL;DR: In this paper, a coupled electro-mechanical analysis of piezoelectric ceramic (PZT) actuators integrated in mechanical systems to determine the actuator power consumption and energy transfer is presented.
Abstract: This article presents a coupled electro-mechanical analysis of piezoelectric ceramic (PZT) actuators integrated in mechanical systems to determine the actuator power consumption and energy transfer in the electro-mechanical systems. For a material system with integrated PZT actua tors, the power consumed by the PZT actuators consists of two parts: the energy used to drive the system, which is dissipated in terms of heat as a result of the structural damping, and energy dissi pated by the PZT actuators themselves because of their dielectric loss and internal damping. The coupled analysis presented herein uses a simple model, a PZT actuator-driven one-degree-of- freedom spring-mass-damper system, to illustrate the methodology used to determine the actuator power consumption and energy flow in the coupled electro-mechanical systems. This method can be applied to more complicated mechanical structures or systems, such as a fluid-loaded shell for active structural acoustic control. The determination of the act...
741 citations
TL;DR: In this article, the behavior of piezoelectric elements as strain sensors is investigated and the performance of PZT and PVDF sensors compared with conventional foil strain gages is demonstrated.
Abstract: This paper investigates the behavior of piezoelectric elements as strain sensors. Strain is measured in terms of the charge generated by the element as a result of the direct piezoelectric ef- fect. Strain measurements from piezoceramic (PZT) and piezofilm (PVDF) sensors are compared with strains from a conventional foil strain gage and the advantages of each type of sensor are dis- cussed, along with their limitations. The sensors are surface bonded to a beam and are calibrated over a frequency range of 5-500 Hz. Correction factors to account for transverse strain and shear lag ef- fects due to the bond layer are analytically derived and experimentally validated. The effect of tem- perature on the output of PZT strain sensors is investigated. Additionally, design of signal condition- ing electronics to collect the signals from the piezoelectric sensors is addressed. The superior performance of piezoelectric sensors compared to conventional strain gages in terms of sensitivity and signal to noise ratio is demonstrated.
624 citations
TL;DR: In this article, the use of highfrequency structural excitations through a surface-bonded piezoelectric sensor/actuator is proposed to detect changes in structural point impedance due to the presence of damage.
Abstract: This paper presents experimental evidence on the use of the impedance-based health-monitoring technique on components typical of civil structures. The basic principle behind this technique is to utilize high-frequency structural excitations (typically >30 kHz) through a surface-bonded piezoelectric sensor/actuator to detect changes in structural point impedance due to the presence of damage. Real-time damage detection on composite-reinforced concrete walls was investigated and the capability of this technique to detect imminent damage, well in advance of actual failure, was confirmed. Concepts that directly applied to this technique itself, such as effects of boundary condition changes and the effects of temperature changes, were also investigated. Experimental investigations were carried out on a 1/4-scale bridge element and a pipe joint commonly found in civil structures, to verify robustness of the technique to changes in environmental conditions. Data collected from the tests demonstrate the capabilit...
460 citations
TL;DR: In this paper, the authors present the results of a health monitoring study, carried out during the destructive load testing of a prototype reinforced concrete (RC) bridge, which represented a popular class of road bridges in which regular health monitoring is a very important issue during the service life.
Abstract: This paper presents the results of a health monitoring study, carried out during the destructive load testing of a prototype reinforced concrete (RC) bridge. The bridge was made up of cement-concrete reinforced with steel rods, and represented a popular class of road bridges in which regular health monitoring is a very important issue during the service life. The bridge was instrumented with piezoceramic transducer (PZT) patches, which were electrically excited at high frequencies, of the order of kHz, and the real part of admittance (conductance) was extracted as a function of the exciting frequency. The patches were scanned for the acquisition of this signature at various stages during the loading process. The signatures of the patches located in the vicinity of the damage were found to have undergone drastic changes, while those farther away were less affected. Damage was quantified in non-parametric terms using the root mean square of the deviation in signatures with respect to the baseline signature of the healthy state. This non-parametric index was found to correlate well with the damage progression in the structure.
366 citations
"A refined shear lag model for adhes..." refers background or methods in this paper
...The frequency range is limited to 0–250 kHz, since for most of the civil engineering applications (Soh et al., 2000), a sub-range within 0–250 kHz is adequate....
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...…has emerged as a competitive and prospective technique for structural health monitoring (SHM) and nondestructive evaluation (NDE) for wide spectrum of structures (Ayres et al., 1998; Bhalla and Soh, 2004a, 2004b; Lim et al., 2006; Park et al., 2006; Shanker et al., 2011; Soh et al., 2000)....
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...During the last two decades, the EMI technique has emerged as a competitive and prospective technique for structural health monitoring (SHM) and nondestructive evaluation (NDE) for wide spectrum of structures (Ayres et al., 1998; Bhalla and Soh, 2004a, 2004b; Lim et al., 2006; Park et al., 2006; Shanker et al., 2011; Soh et al., 2000)....
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