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.

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.

Interface debonding performance of precast segmental nano-materials based concrete (PSNBC) beams

2020 ◽  
Vol 10 (8) ◽  
pp. 1317-1327 ◽  
Author(s):  
Xinfeng Yin ◽  
Ming Zhang ◽  
Lei Wang ◽  
Yang Liu
Keyword(s):  
Lead Zirconate Titanate ◽  
High Strength ◽  
Concrete Specimen ◽  
Lead Zirconate ◽  
Epoxy Adhesive ◽  
Interface Debonding ◽  
Nano Materials ◽  
Monitoring Test ◽  
Physical Effects ◽  
Better Than

The precast segmental concrete (PSC) structures and the nano-materials based concrete beams are widely applied to civil engineering. On the other hand, it is well known that nano-materials have physical effects and can significantly improve the concrete properties of cement-based materials. Therefore, the interface debonding performance of precast segmental nano-materials based concrete (PSNBC) beams is investigated in this study. Two concrete specimens with nano-materials and one concrete specimen without nano-materials were prepared and bonded into PSC beams with a high strength epoxy adhesive. The smart aggregates (SAs) made of piezoceramic Lead Zirconate Titanate (PZT) and concrete are used as the intelligent transducer of monitoring test specimen. The PSC beam was loaded periodically by screw jack to simulate the random debonding damage of different degrees. The experimental results show that the interface debonding performance of the concrete specimens with nano-materials is significantly enhanced and better than that of concrete specimens without nano-materials.

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.

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.

scholarly journals Damage assessment in concrete structures using piezoelectric based sensors

2017 ◽  
Vol 7 (1) ◽  
pp. 25-35 ◽  
Author(s):  
A. Narayanan ◽  
K. V. L. Subramaniam
Keyword(s):  
Lead Zirconate Titanate ◽  
Damage Assessment ◽  
Concrete Structures ◽  
Electrical Conductance ◽  
Mechanical Impedance ◽  
Lead Zirconate ◽  
Internal Damage ◽  
Zirconate Titanate ◽  
Resonant Behavior ◽  
Damage In Concrete

Damage assessment in concrete structures using piezoelectric based sensorsABSTRACTPiezoelectric based PZT (Lead Zirconate Titanate) smart sensors offer significant potential for continuously monitoring the development and progression of internal damage in concrete structures. Changes in the resonant behavior in the measured electrical conductance obtained from electro-mechanical (EM) response of a PZT bonded to a concrete substrate is investigated for increasing levels of damage. Changes in the conductance resonant signature from EM conductance measurements are detected before visible signs of cracking. The root mean square deviation of the conductance signature at resonant peaks is shown to accurately reflect the level of damage in the substrate. The findings presented here provide a basis for developing a sensing methodology using PZT patches for continuous monitoring of concrete structures.Keywords: PZT; electro-mechanical impedance; conductance; microcracks.Evaluación de daños en estructuras de concreto utilizando sensores piezoeléctricosRESUMENLos sensores inteligentes PZT (Lead Zirconate Titanate) basados en piezoeléctricos ofrecen un potencial significativo para monitorear continuamente el desarrollo y la progresión de los daños internos en estructuras de concreto. Se investigan los cambios en el comportamiento resonante a través de la conductancia eléctrica medida, obtenida a partir de la respuesta electromecánica (EM) de un PZT unido a un sustrato de concreto para aumentar los niveles de daño. Los cambios en la resonancia de la conductancia EM se detectan antes de que aparezcan signos visibles de agrietamiento. La desviación cuadrática media de la raíz de la conductancia en los picos resonantes refleja con precisión el nivel de daño en el sustrato. Los hallazgos presentados aquí proporcionan una base para desarrollar una metodología de detección utilizando parches PZT para el monitoreo continuo de estructuras de concreto.Palabras clave: PZT; impedancia electromecánica; conductancia; microfisuras.Avaliação de danos em estruturas de concreto usando sensores piezoelétricos RESUMOOs sensores piezoelétricos inteligentes PZT (Lead Zirconate Titanate) oferecem um potencial significativo para o monitoramento contínuo do desenvolvimento e progressão de danos internos em estruturas de concreto. As alterações de ressonância através da medida da condutância elétrica obtida a partir da resposta eletromecânica (EM) de um PZT ligado a um substrato de concreto é investigada para níveis crescentes de danos. As alterações no perfil de ressonância de condutância EM são detectadas antes de sinais visíveis de fissuras. O desvio quadrático médio da raiz do perfil de condutância nos picos ressonantes é mostrado para refletir com precisão o nível de dano no substrato. Os resultados aqui apresentados fornecem uma base para o desenvolvimento de uma metodologia de detecção usando PZT para monitoramento contínuo de estruturas de concretoPalavras chave: PZT; impedância eletromecânica; condutância; microfissuras.

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.

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.

Intelligent design in continuous galvanizing process for advanced ultra-high-strength dual-phase steels using back-propagation artificial neural networks and MOAMP-Squirrels search algorithm

2020 ◽  
Vol 110 (9-10) ◽  
pp. 2619-2630 ◽  
Author(s):  
Gerardo Altamirano-Guerrero ◽  
Irma D. García-Calvillo ◽  
Edgar O. Reséndiz-Flores ◽  
Patricia Costa ◽  
Armando Salinas-Rodríguez ◽  
...  
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Intelligent Design ◽  
Search Algorithm ◽  
Back Propagation ◽  
High Strength ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Artificial Neural
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