scholarly journals Monitoring of Grouting Compactness in Tendon Duct Using Multi-Sensing Electro-Mechanical Impedance Method

2020 ◽  
Vol 10 (6) ◽  
pp. 2018 ◽  
Author(s):  
Bin Guo ◽  
Dongdong Chen ◽  
Linsheng Huo ◽  
Gangbing Song
Keyword(s):  
Lead Zirconate Titanate ◽  
Prestressed Concrete ◽  
Processing Time ◽  
Structural Integrity ◽  
Physical Property ◽  
Mechanical Impedance ◽  
Lead Zirconate ◽  
Measurement Procedure ◽  
Impedance Method ◽  
Single Measurement

The structural integrity of post-tensioning prestressed concrete structures with tendon ducts highly depends on the grouting quality in construction. This paper proposes a real-time approach to monitoring the grouting compactness in tendon ducts using the multi-sensing electro-mechanical impedance (EMI) method. When Lead Zirconate Titanate (PZT) transducers with different pre-selected dimensions are serially connected and mounted on a structure at distributed locations, each PZT provides unique resonance frequency coupled with the local structural physical property. Therefore, the impedance with multiple peaks of the serially connected multiple PZTs can be captured during a single measurement, which significantly simplifies the measurement procedure and reduces the data processing time. In addition, the wiring for the PZT sensors is also simplified. In this research, the feasibility of the proposed method was experimentally and numerically investigated to monitor the grouting compactness in a tendon duct specimen. The 3-dB mean absolute percentage deviation (MAPD) was applied to quantify the variations of the impedance signatures measured from five different grouting levels. Both experimental and numerical results verify the feasibility of using the proposed method for monitoring the grouting compactness in tendon ducts.

scholarly journals Corrosion assessment of structural components using electro mechanical impedance

2021 ◽  
Vol 309 ◽  
pp. 01208
Author(s):  
N. Naga Sai Pravallika ◽  
V. Mallikarjuna Reddy ◽  
B. Siva Konda Reddy
Keyword(s):  
Lead Zirconate Titanate ◽  
Structural Integrity ◽  
Piezoelectric Materials ◽  
Mechanical Impedance ◽  
Lead Zirconate ◽  
Health Condition ◽  
Linear Perturbation ◽  
Structural Components ◽  
Element Analysis ◽  
Impedance Technique

Rapid innovation in interdisciplinary technology emphasized the data acquisition system to evaluate the structural integrity by combining with advance sensing techniques. These smart sensors with impedance methodology has shown an excellent potential in assessing the structural health condition and provided an alternative to many sophisticated Non destructive monitoring systems. The sensitivity of electro mechanical impedance technique in detecting local incipient damages is enhanced with piezoelectric mechanism of lead zirconate titanate materials and with conductance signatures these materials can determine the dynamic variations in structural properties more effectively. In the present work numerical finite element analysis is conducted on simply supported RCC beam in Abaqus software with reinforcement subjected to corrosion in five stages with different reduction rates and coupled with piezoelectric transducers along the length to implement the impedance strategy. These surface bonded piezoelectric patches are electrically excited with an external voltage under specific frequency range to conduct linear perturbation harmonic analysis and the output conductance responses of healthy and corroded beams from different sensor locations are captured and compared. The peak shifting nature of signature pattern will serve as an indicator to diagnose the corrosion severity and propagation in structural components. The simulation results of proposed impedance technique showed the feasibility of employing piezoelectric materials to identify corrosion activity in structural members with electromechanical conductivity signatures.

Interfacial debonding detection in fiber-reinforced polymer rebar–reinforced concrete using electro-mechanical impedance technique

2017 ◽  
Vol 17 (3) ◽  
pp. 461-471 ◽  
Author(s):  
Weijie Li ◽  
Shuli Fan ◽  
Siu Chun Michael Ho ◽  
Jianchao Wu ◽  
Gangbing Song
Keyword(s):  
Reinforced Concrete ◽  
Lead Zirconate Titanate ◽  
Health Monitoring ◽  
Mechanical Impedance ◽  
Lead Zirconate ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Monitoring Technique

For reinforced concrete structures, the use of fiber-reinforced polymer rebars to replace the steel reinforcement is a topic that is receiving increasing attention, especially where corrosion is a serious issue. However, fiber-reinforced polymer rebar–reinforced concrete always carries the risk of structural failure initiated from the debonding damage that might occur at the reinforcement–concrete interface. This study employed an electro-mechanical impedance–based structural health monitoring technique by applying lead–zirconate–titanate ceramic patches to detect the debonding damage of a carbon fiber–reinforced polymer rebar reinforced concrete. In the experimental study, a carbon fiber–reinforced polymer rebar reinforced concrete specimen was fabricated and it was subjected to a pullout test to initiate the debonding damage at the reinforcement–concrete interface. The impedance and admittance signatures were measured from an impedance analyzer according to the different debonding conditions between the reinforcement and the concrete. Statistical damage metrics, root-mean-square deviation and mean absolute percentage deviation, were used to quantify the changes in impedance signatures measured at the lead–zirconate–titanate patches due to debonding conditions. The results illustrated the capability of the electro-mechanical impedance–based structural health monitoring technique for detecting the debonding damage of fiber-reinforced polymer rebar–reinforced concrete structures.

Evaluation of the ISHM Method Applied for Composite Rotors

2019 ◽  
Author(s):  
Karina M. Tsuruta ◽  
Lucas A. A. Rocha ◽  
Aldemir Ap. Cavalini ◽  
Roberto M. Finzi Neto ◽  
Valder Steffen
Keyword(s):  
Lead Zirconate Titanate ◽  
Electrical Impedance ◽  
Optimization Procedure ◽  
Mechanical Impedance ◽  
Lead Zirconate ◽  
Sensors And Actuators ◽  
Present Contribution ◽  
Structure Damage ◽  
Electromechanical Impedance ◽  
Rotor Shaft

Abstract The use of SHM (structural health monitoring) techniques has shown promising results for fault detection in rotating machines, making possible to identify various malfunctions. SHM methods provide maintainability and safe operation for these systems. The objective of the present work is to evaluate the SHM method based on the electromechanical impedance (ISHM) to detect faults in a composite rotor shaft. Composite materials present complex damage mechanisms due to their anisotropy and heterogeneity. Moreover, the process of damage detection in these materials is more challenging than in metallic structures. The ISHM approach uses piezoelectric (PZT – Lead Zirconate Titanate) patches as sensors and actuators coupled to the monitored structure. Variations in their electrical impedance are associated with changes in the mechanical integrity of the system. The electrical impedance of the PZT sensor is directly related to the mechanical impedance of the structure, which changes according to variations in the mass, stiffness, and damping properties of the structure. Damage metrics are used to quantify variations in the electrical impedance (impedance signatures) of the PZT patches. Despite the ISHM approach be able to detect incipient faults, it presents some disadvantages. For instance, the impedance signatures are susceptible to temperature variation. In the present contribution, to detect damages in the considered composite rotor shaft, the ISHM technique was implemented based on a data normalization methodology. Thus, an optimization procedure based on hybrid optimization was used to avoid false diagnostics.

scholarly journals Looseness Monitoring of Bolted Spherical Joint Connection Using Electro-Mechanical Impedance Technique and BP Neural Networks

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1906 ◽  
Author(s):  
Jing Xu ◽  
Jinhui Dong ◽  
Hongnan Li ◽  
Chunwei Zhang ◽  
Siu Chun Ho
Keyword(s):  
Neural Networks ◽  
Lead Zirconate Titanate ◽  
Back Propagation ◽  
Mechanical Impedance ◽  
High Strength ◽  
Lead Zirconate ◽  
Spherical Joint ◽  
High Strength Bolt ◽  
Space Grid ◽  
Joint Connection

The bolted spherical joint (BSJ) has wide applications in various space grid structures. The bar and the bolted sphere are connected by the high-strength bolt inside the joint. High-strength bolt is invisible outside the joint, which causes the difficulty in monitoring the bolt looseness. Moreover, the bolt looseness leads to the reduction of the local stiffness and bearing capacity for the structure. In this regard, this study used the electro-mechanical impedance (EMI) technique and back propagation neural networks (BPNNs) to monitor the bolt looseness inside the BSJ. Therefore, a space grid specimen having bolted spherical joints and tubular bars was considered for experimental evaluation. Different torques levels were applied on the sleeve to represent different looseness degrees of joint connection. As the torque levels increased, the looseness degrees of joint connection increased correspondingly. The lead zirconate titanate (PZT) patch was used and integrated with the tubular bar due to its strong piezoelectric effect. The root-mean-square deviation (RMSD) of the conductance signatures for the PZT patch were used as the looseness-monitoring indexes. Taking RMSD values of sub-frequency bands and the looseness degrees as inputs and outputs respectively, the BPNNs were trained and tested in twenty repeated experiments. The experimental results show that the formation of the bolt looseness can be detected according to the changes of looseness-monitoring indexes, and the degree of bolt looseness by the trained BPNNs. Overall, this research demonstrates that the proposed structural health monitoring (SHM) technique is feasible for monitoring the looseness of bolted spherical connection in space grid structures.

scholarly journals Integrated Structural Health Assessment Using Piezoelectric Active Sensors

2005 ◽  
Vol 12 (6) ◽  
pp. 389-405 ◽  
Author(s):  
Jeannette R. Wait ◽  
Gyuhae Park ◽  
Charles R. Farrar
Keyword(s):  
Lamb Wave ◽  
Structural Damage ◽  
Structural Integrity ◽  
Damage Identification ◽  
Wave Attenuation ◽  
Health Assessment ◽  
Mechanical Impedance ◽  
Integrated Approach ◽  
Impedance Method ◽  
Sensing Technology

This paper illustrates an integrated approach for identifying structural damage. The method presented utilizes piezoelectric (PZT) materials to actuate/sense the dynamic response of the structures. Two damage identification techniques are integrated in this study, including impedance methods and Lamb wave propagations. The impedance method monitors the variations in structural mechanical impedance, which is coupled with the electrical impedance of the PZT patch. In Lamb wave propagations, one PZT patch acting as an actuator launches an elastic wave through the structure, and responses are measured by an array of PZT sensors. The changes in both wave attenuation and reflection are used to detect and locate the damage. Both the Lamb wave and impedance methods operate in high frequency ranges at which there are measurable changes in structural responses even for incipient damage such as small cracks, debonding, or loose connections. The combination of the local impedance method with the wave propagation based approach allows a better characterization of the system’s structural integrity. The paper concludes with experimental results to demonstrate the feasibility of this integrated active sensing technology.

Preparation of Highly Loaded Piezo-Composite Foams With High Expansion and Low Permittivity

2017 ◽  
Author(s):  
Gayaneh Petrossian ◽  
Amir Ameli
Keyword(s):  
Dielectric Permittivity ◽  
Lead Zirconate Titanate ◽  
Structural Integrity ◽  
Thermoplastic Polyurethane ◽  
High Sensitivity ◽  
Lead Zirconate ◽  
Gas Diffusion ◽  
Expansion Ratio ◽  
Composite Foams ◽  
The Matrix

The sensitivity of piezoelectric/polymer composite materials is inversely proportional to their dielectric permittivity. Introducing a cellular structure into these composites can decrease the permittivity while enhancing their mechanical flexibility. Foaming of highly filled polymer composites is however challenging. Polymers filled with high content of dense additives such as lead zirconate titanate (PZT) exhibit significantly decreased physical foaming ability. This can be attributed to difficulty in gas diffusion, decreased fraction of the matrix available, the reduced number of nucleated cells and the difficulty in cell growth. Here, both CO2 foaming and Expancel foaming were examined as potential methods to fabricate low-density thermoplastic polyurethane (TPU)/ PZT composite foams. While composites containing up to only 10vol.% PZT could be foamed using CO2, Expancel foaming could successfully yield highly-expanded composite foams containing up to 40vol.% (80wt.%) PZT. Dispersed Expancel particles in TPU/PZT composites acted as the blowing agent, activated by subjecting the samples to high temperatures using a hot press. Using Expancel, foams with expansion ratios of up to 9 were achieved. However, expansion ratios of greater than 4 were not of interest due to their poor structural integrity. The density of solid samples ranged from 1.8 to 3.3 g.cm−3 and dropped by a maximum of 80%, even for the highest PZT content, at an expansion ratio of 4. As the expansion increased, the dielectric permittivity of both CO2-foamed and Expancel-foamed TPU/PZT composites decreased significantly (up to 7.5 times), while the dielectric loss and electrical conductivity were affected only slightly. This combination of properties is suitable for high-sensitivity and flexible piezoelectric applications.

Piezoelectricity

2004 ◽  
Author(s):  
Robert E. Newnham
Keyword(s):  
Electric Field ◽  
Coordinate System ◽  
Lead Zirconate Titanate ◽  
Piezoelectric Effect ◽  
Piezoelectric Materials ◽  
Mechanical Strain ◽  
Physical Property ◽  
Lead Zirconate ◽  
Quartz Crystals ◽  
Rank Tensor

The prefix “piezo” (pronounced pie-ease-o) comes from the Greek word for pressure or mechanical force. Piezoelectricity refers to the linear coupling between mechanical stress and electric polarization (the direct piezoelectric effect) or between mechanical strain and applied electric field (the converse piezoelectric effect). The equivalence between the direct and converse effects was established earlier using thermodynamic arguments (Section 6.2). The principal piezoelectric coefficient, d, relates polarization, P, to stress, X, in the direct effect (P = dX) and strain, x, to electric field E (x = dE). Thus the units of d are [C/N] or [m/V] which are equivalent to one another. Typical sizes for useful piezoelectric materials range from about 1 pC/N for quartz crystals to about 1000 pC/N for PZT (lead zirconate titanate) ceramics. To understand how the piezoelectric effect varies with direction and how it is affected by symmetry, it is necessary to determine how piezoelectric coefficients transform between coordinate systems. Since polarization is a vector and stress a second rank tensor, the physical property relating these two variables must involve three directions: . . . Pj = djklXkl . . . . In the new coordinate system . . . P'i = aijPj = aijdjklXkl . . . . Transforming the stress to the new coordinate system gives . . . P'i= aijdjklamkanlX'mn = d'imnX 'mn. . . . Thus piezoelectricity transforms as a polar third rank tensor. . . . d'imn = aijamkanldjkl . . . . In general there are 33 = 27 tensor components, but because the stress tensor is symmetric (Xij = Xji), only 18 of the components are independent. Therefore the piezoelectric effect can be described by a 6 × 3 matrix.

Structural Parameters Identification Using PZT Sensors and Genetic Algorithms

2009 ◽  
Vol 79-82 ◽  
pp. 63-66
Author(s):  
Yao Wen Yang ◽  
Ai Wei Miao
Keyword(s):  
Genetic Algorithms ◽  
Structural Properties ◽  
Lead Zirconate Titanate ◽  
Structural Damage ◽  
Structural Parameters ◽  
Excitation Frequency ◽  
Mechanical Impedance ◽  
Lead Zirconate ◽  
Physical Parameters ◽  
Optimal Values

Piezoelectric ceramic lead zirconate titanate (PZT) based electro-mechanical impedance (EMI) technique for structural health monitoring (SHM) has been successfully applied to various engineering systems [1-5]. In the traditional EMI method, statistical analysis methods such as root mean square deviation indices of the PZT electromechanical (EM) admittance are used as damage indicator, which is difficult to specify the effect of damage on structural properties. This paper proposes to use the genetic algorithms (GAs) to identify the structural parameters according to the changes in the PZT admittance signature. The basic principle is that structural damage, especially local damage, is typically related to changes in the structural physical parameters. Therefore, to recognize the changes of structural parameters is an effective way to assess the structural damage. Towards this goal, a model of driven point PZT EM admittance is established. In this model, the dynamic behavior of the structure is represented by a multiple degree of freedom (DOF) system. The EM admittance is formulated as a function of excitation frequency and the unknown structural parameters, i.e., the mass, stiffness and the damping coefficient of many single DOF elements. Using the GAs, the optimal values of structural parameters in the model can be back-calculated such that the EM admittance matches the target value. In practice, the target admittance is measured from experiments. In this paper, we use the calculated one as the target. For damage assessment, these optimal values obtained before and after the appearance of structural damage can be compared to study the effects of damage on the structural properties, which are specified to be stiffness and damping in this study. Furthermore, the identified structural parameters could be used to predict the remaining loading capacity of the structure, which serves the purpose for damage prognosis.

Micro- and Macroscopic Observations of the Microtexture, the Dielectric and Piezoelectric Properties in Bulk and Multilayer Pb (Zr, Ti)O3

2008 ◽  
Vol 55-57 ◽  
pp. 45-48
Author(s):  
N. Binhayeeniyi ◽  
A. Dasaesamoh ◽  
J. Khakong ◽  
P. Khaenamkaew ◽  
S. Muensit
Keyword(s):  
Lead Zirconate Titanate ◽  
Piezoelectric Properties ◽  
Sol Gel ◽  
Physical Property ◽  
Lead Zirconate ◽  
Solid State Method ◽  
Fundamental Properties ◽  
The Subject ◽  
Gel Technique ◽  
Dielectric And Piezoelectric Properties

The objective of the present paper is to give an insight of the fundamental properties strongly depended on the crystallizing phase, grain size, thickness, including stoichiometry of material. The subject of this work is the lead zirconate titanate [Pb(Zr,Ti)O3, PZT] with its composition located at the morphotropic phase boundary (MPB) that were prepared by a solid state method [1] and a conventional sol-gel technique [2,3]. The samples prepared by the first methods are in a bulk form while the latter the multilayer. The physical property and the dielectric and piezoelectric properties of the PZT samples have been discussed comparatively when the sample size decreasing from the bulk to the thin-film scale.

Assessment of human bones encompassing physiological decay and damage using piezo sensors in non-bonded configuration

2017 ◽  
Vol 28 (14) ◽  
pp. 1977-1992 ◽  
Author(s):  
Shashank Srivastava ◽  
Suresh Bhalla ◽  
Alok Madan
Keyword(s):  
Lead Zirconate Titanate ◽  
Mechanical Impedance ◽  
Lead Zirconate ◽  
Biomedical Sensors ◽  
Human Bones ◽  
Zirconate Titanate ◽  
Artificial Bones ◽  
Sensor Configuration

In the recent years, several biomedical applications of lead zirconate titanate piezo-electric ceramic patches based on the electro-mechanical impedance technique have been reported in the literature. However, practical application of the technique on live subjects is severely hampered due to the requirement of bonding the patch with bone or cartilage with an adhesive. In addition, live subjects have skin cover over the bone. This article proposes and evaluates the feasibility of employing lead zirconate titanate patches as biomedical sensors in non-bonded configuration for assessing the physiological conditions of bones. For this purpose, a special design is proposed where the lead zirconate titanate patch is first bonded on a thin aluminum strip, which is in turn clamped securely on the biomedical subject. The proposed configuration is investigated both in vitro and in vivo. The non-bonded piezo sensors are first investigated to identify dynamic parameters of the bone through lab-based experimental study involving artificial bones. Thereafter, physiological damage and decay conditions are artificially simulated in the experimental bones and the same are correlated with changes in conductance signatures from the non-bonded piezo sensor as well as the lead zirconate titanate patch in the conventional adhesively bonded (direct bonding to the subject) configuration. The trend of the conductance signatures in the healthy and the damaged conditions from the non-bonded piezo sensor is found to correlate well with the corresponding signatures from the directly bonded piezo sensor. At the same time, the repeatability of the signatures is also found to be satisfactory. After success in bare bones, the non-bonded piezo sensor configuration is extended to monitor the condition of bones covered with skin and tissue, simulated in the lab with the aid of silicone-based coating. Finally, a proof-of-concept experiment on a live human subject is successfully demonstrated. The overall results of the study demonstrate very good prospects of employing lead zirconate titanate patches in non-bonded piezo sensor mode for monitoring the condition of human bones and other related biomedical subjects.

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