scholarly journals Multi-Scale Stress Wave Simulation for Aggregates Segregation Detection of Concrete Core in Circular CFST Coupled with PZT Patches

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1223 ◽  
Author(s):  
Hongbing Chen ◽  
Bin Xu ◽  
Yilung Mo ◽  
Tianmin Zhou
Keyword(s):  
Stress Wave ◽  
Lead Zirconate Titanate ◽  
Coupling Effect ◽  
Wavelet Packet ◽  
Lead Zirconate ◽  
Stress Wave Propagation ◽  
Voltage Response ◽  
Concrete Aggregate ◽  
Concrete Core ◽  
Multi Scale

In this study, the numerical investigation of the detectability of concrete aggregate segregation in circular concrete-filled steel tubulars (CCFST) based on piezoelectric lead zirconate titanate (PZT) measurement is performed. The stress wave propagation in the concrete core of circular CCFST excited with a surface-mounted PZT actuator is studied with multi-scale and multi-physical field coupling analysis. The piezoelectric effect of PZT patches and its coupling effect with CFSTs are considered. Numerical concrete modeling technology is employed to construct the concrete core composed of randomly distributed aggregates with and without aggregate segregation at different levels, mortar, and an interfacial transition zone (ITZ). The effects of the random distribution of elliptical aggregates, aggregate segregation, and the existence of ITZ in the concrete core on the wave fields in the cross-section and the corresponding voltage response of the embedded PZT sensor are discussed. An evaluation index based on wavelet packet analysis on the output voltage response is defined, and its sensitivity to concrete aggregate segregation is systematically investigated. The multi-scale and multi-physics coupling simulation results indicate that concrete aggregate segregation in the concrete core of CFST members can be efficiently detected based on the stress wave measurement with a PZT sensor.

scholarly journals Detecting Debonding between Steel Beam and Reinforcing CFRP Plate Using Active Sensing with Removable PZT-Based Transducers

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 41 ◽  
Author(s):  
Jian Jiang ◽  
Jinwei Jiang ◽  
Xiaowei Deng ◽  
Zifeng Deng
Keyword(s):  
Stress Wave ◽  
Lead Zirconate Titanate ◽  
Wavelet Packet ◽  
Experimental Studies ◽  
Steel Structure ◽  
Steel Structures ◽  
Lead Zirconate ◽  
Steel Beam ◽  
Active Sensing ◽  
Cfrp Plate

Carbon fiber reinforced polymer (CFRP) plates are widely used to retrofit or reinforce steel structures, and the debonding damage between the steel structure and the CFRP plate is a typical failure in strengthening steel structures. This paper proposes a new approach to detecting debonding between a steel beam and a reinforcing CFRP plate by using removable lead zirconate titanate (PZT)-based transducers and active sensing. The removable PZT-based transducers are used to implement the active sensing approach, in which one transducer, as an actuator, is used to generate stress wave, and another transducer, as a sensor, is used to detect the stress wave that propagates across the bonding between the steel beam and the reinforcing CFRP plate. The bonding condition significantly influences the received sensor signal, and a wavelet-packet-based energy index (WPEI) is used to quantify the energy of the received signal to evaluate the severity of debonding between the steel beam and the reinforcing CFRP plate. To validate the proposed approach, experimental studies were performed, and two removable PZT-based transducers were designed and fabricated to detect the debonding between a steel beam and the reinforcing CRFP plate. The experimental results demonstrate the feasibility of the proposed method in detecting the debonding between a steel beam and the reinforcing CFRP plate using removable PZT-based transducers.

scholarly journals Monitoring bond-slip behavior of CFRP-RCESC beams using piezoelectric active sensing method

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Tianyong Jiang ◽  
Donghai Yu ◽  
Min Xiao ◽  
Lingyun Li ◽  
Lei Wang
Keyword(s):  
Reinforced Concrete ◽  
Stress Wave ◽  
Lead Zirconate Titanate ◽  
Wavelet Packet ◽  
Lead Zirconate ◽  
Active Sensing ◽  
Bond Slip ◽  
Damage States ◽  
Damage Process ◽  
As Stress

AbstractCombination of carbon fiber reinforced polymer (CFRP) tendon and reinforced concrete encased steel composite (RCESC) beam can improve the workability and the energy dissipation capacity of members. In this paper, three RCESC beams reinforced with steel bars or CFRP bars were designed and fabricated to study the bond-slip behavior between I-shaped steel and CFRP reinforced concrete and the damage states between bond-slip interfaces of the beams. The lead zirconate titanate (PZT) patch as stress wave actuator, the smart aggregates (SAs) were installed in concrete as the sensors to collect the stress wave signal. A method based on piezoelectric active sensing was developed to monitor the bond-slip damage of CFRP-RCESC beam. The changes of responding signals were characterized in time- and frequency- domains. The characteristic information of bond-slip damage was further quantified by wavelet packet energy. Results show the bond-slip resistance of the CFRP-RCESC beams can be improved by increasing reinforcement ratio and elastic modulus of the main bars. The bond-slip damage process of the specimens can be effectively monitored by the active sensing method.

scholarly journals Feasibility Study on Grouting Compactness Detection in Sleeves Using Piezoelectric Transducers

2019 ◽  
Vol 10 (1) ◽  
pp. 149 ◽  
Author(s):  
Chen Wu ◽  
Chao Yang ◽  
Shenglan Ma ◽  
Xiaoliang Xu
Keyword(s):  
Stress Wave ◽  
Lead Zirconate Titanate ◽  
Wavelet Packet ◽  
Outer Wall ◽  
Lead Zirconate ◽  
Correction Model ◽  
Hilbert Huang Transform ◽  
Energy Peak ◽  
Steel Sleeve ◽  
To Receive

Steel sleeve grouting connections are widely used in prefabricated concrete structures. It is well known that insufficient grouting increases the chance of structural failure. As such, it is critical to monitor the density and compactness of grouting sleeve during the construction process, which however remains significant challenges as it is deeply buried in the beam and column. In this study, a lead zirconate titanate (PZT)-based sleeve grouting compactness detection method was systematically investigated. Five grouting sleeves samples with different degrees of compactness were prepared and four PZT transducers were surface-bonded on opposite sides of the outer wall of each sleeve. Two acts as actuators to generate stress wave signals, and the other two operate as sensors to receive the signals. The wavelet packet energy and Hilbert–Huang transform methods were applied to process the stress wave signals, and with the chosen characteristic parameters, the correction model of the grouting compactness was established. Experimental results show that the wavelet packet total energy values and the Hilbert energy peak values are related to the grouting compactness, indicating the feasibility of using PZT sensors to detect the compactness of grouting sleeves.

Estimate buried metal pipe length using PZT detected stress wave reflection

2020 ◽  
pp. 1045389X2096605
Author(s):  
Chuan Xu ◽  
Mingzhang Luo ◽  
Chuang Hei ◽  
Gangbing Song
Keyword(s):  
Stress Wave ◽  
Lead Zirconate Titanate ◽  
Wave Reflection ◽  
Wavelet Denoising ◽  
Lead Zirconate ◽  
Time Interval ◽  
Pipe Length ◽  
Metal Pipe ◽  
Metal Pipes ◽  
Reflected Signal

A roadway guardrail, as the driver’s last safety barrier, is an important part of a transportation system. The buried depth of the metal pipe directly determines the bearing capacity of the guardrail during an impact. It is important to estimate the buried depth during the inspection of a guardrail system. In this paper, we proposed an original method by integrating wavelet denoising, multiple self-correlation analysis (MSA) and energy spectrum analysis (ESA) to estimate the length of buried metal pipe based on the stress wave reflection. The stress wave is initiated by an impact on the exposed end of the buried pipe and stress wave reflection is detected by a PZT (Lead Zirconate Titanate) transducer. To execute the proposed method, firstly, Wavelet denoising is used to process the reflected stress wave signal to improve the signal-to-noise ratio. Then, the MSA detects the major frequency of the reflected signal. At last, the ESA extracts the time interval between the reflected signal and the excitation signal with the help of Short Time Fourier Transform (STFT) that acquires the frequency band where the reflected signal is located. Experimental verifications were carried out, and two different lengths of buried metal pipes are selected to verify the feasibility of the proposed method. The experimental results indicate that the proposed method can accurately extract the length of buried metal pipes. The superiority of the proposed method over the traditional methods, such as Peak-Peak Discriminance (PPD) and Phase Analysis Method (PAM), is demonstrated by experimental comparative studies.

Tunable Energy Harvesting From Ambient Vibrations

2010 ◽  
Author(s):  
Mohamed Rhimi ◽  
Nizar Lajnef
Keyword(s):  
Energy Harvesting ◽  
Lead Zirconate Titanate ◽  
Coupling Effect ◽  
Energy Levels ◽  
Axial Loading ◽  
Lead Zirconate ◽  
Energy Scavenging ◽  
Ambient Vibrations ◽  
Civil Structures ◽  
Piezoelectric Energy

Most civil structures have a low vibration response frequency range, generally one to two orders of magnitude lower than the operating frequency spectrum of most piezoelectric energy scavenging devices, which is dictated by the device’s design and the used materials. This considerably limits the levels of harvestable power under ambient vibrations. In this paper, the improvement of the energy harvesting characteristics of a bimorph cantilever lead zirconate titanate (PZT) piezoelectric beam through the application of initial pre-stress loading conditions is studied. A generalized model that can take into account all the vibration modes of the beam as well as the back coupling effect is derived using the Hamiltonian principle. The model describes the effect of the pre-stress parameters on the harvestable energy levels. Results showing the variations of the natural frequency, amplitude, and efficiency of the piezoelectric device with varying preload are presented. Vibration recordings from a bridge under ambient loading are used to show variations of the harvested power with different pre-stress conditions. Increases of up to 250% in the output power levels are shown possible through the application of 8N of compressive axial loading for a system with a 15g vibrating mass. Experimental verification of the model is also performed. The time and frequency domain responses of a piezoelectric bimorph are measured and compared to theoretical results.

scholarly journals Prestress Monitoring of a Steel Strand in an Anchorage Connection Using Piezoceramic Transducers and Time Reversal Method

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4018 ◽  
Author(s):  
Xiaoyu Zhang ◽  
Liuyu Zhang ◽  
Laijun Liu ◽  
Linsheng Huo
Keyword(s):  
Stress Wave ◽  
Lead Zirconate Titanate ◽  
Time Reversal ◽  
Stress Wave Propagation ◽  
Suspension Bridges ◽  
Active Sensing ◽  
Sensors And Actuators ◽  
Anchorage System ◽  
Steel Strand ◽  
Peak Value

Steel strands are widely used in cable stay or suspension bridges. The safety and stability of steel strands are important issues during their operation period. Steel strand is subjected to various types of prestress loss which loosens the wedge anchorage system, negatively impacting the stability of the structure and even leading to severe accidents. In this paper, the authors propose a time reversal (TR) method to monitor the looseness status of the wedge anchorage system by using stress wave based active sensing. As a commonly used piezoceramic material, Lead Zirconate Titanate (PZT) with a strong piezoelectric effect is employed. In the proposed active sensing approach, PZT patches are used as sensors and actuators to monitor the steel strand looseness status. One PZT patch is bonded to the steel strand, one PZT patch is bonded to the wedges, and another PZT patch is bonded to the barrel. There are three different interfaces of the wedge anchorage system to monitor the steel strand looseness status. In the first method, the PZT patch on the steel strand is used as an actuator to generate a stress wave and the PZT patch on the wedge is used as a sensor to detect the propagated waves through the wedge anchorage system. In the second method, the PZT patch on the steel strand is used as an actuator to generate a stress wave and the PZT patch on the barrel is used as a sensor to detect the propagated waves through the wedge anchorage system. In the third method, the PZT patch on the wedges is used as an actuator to generate a stress wave and the PZT patches on the barrel is used as a sensor to detect the propagated waves through the wedge anchorage system, of which the looseness will directly impact the stress wave propagation. The TR method is utilized to analyze the transmitted signal between PZT patches through the wedge anchorage system. Compared with the peak values of the TR focused signals, it can be found that the peak value increases as the wedge anchorage system tightness increases. Therefore, the peak value of the TR focused signal can be used to monitor the tightness of the steel strand. In addition, the experimental results demonstrated the time reversal method’s reliability, sensitivity and anti-noise property.

scholarly journals A Feasibility Study on Timber Moisture Monitoring Using Piezoceramic Transducer-Enabled Active Sensing

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3100 ◽  
Author(s):  
Jicheng Zhang ◽  
Yong Li ◽  
Yongshui Huang ◽  
Jinwei Jiang ◽  
Siu-Chun Ho
Keyword(s):  
Moisture Content ◽  
Stress Wave ◽  
Lead Zirconate Titanate ◽  
Structural Damage ◽  
Wave Attenuation ◽  
Lead Zirconate ◽  
Active Sensing ◽  
Non Invasive ◽  
Potential Damage ◽  
Piezoceramic Transducer

In recent years, the piezoceramic transducer-enabled active sensing technique has been extensively applied to structural damage detection and health monitoring, in civil engineering. Being abundant and renewable, timber has been widely used as a building material in many countries. However, one of the more challenging applications of timber, in construction, is the potential damage caused by moisture. Increased moisture may cause easier warping of timber components and encourage corrosion of integrated metal members, on top of potentially causing rot and decay. However, despite numerous efforts to inspect and monitor the moisture content of timber, there lacks a method that can provide truly real time, quantitative, and non-invasive measurement of timber moisture. Thus, the research presented in this paper investigated the feasibility of moisture-content monitoring using an active sensing approach, as enabled by a pair of the Lead Zirconate Titanate (PZT) transducers bonded on the surface of a timber specimen. Using a pair of transducers in an active sensing scheme, one patch generated a designed stress wave, while another patch received the signal. While the active sensing was active, the moisture content of the timber specimen was gradually increased from 0% to 60% with 10% increments. The material properties of the timber correspondingly changed under varying timber moisture content, resulting in a measurable differential in stress wave attenuation rates among the different specimens used. The experimental results indicated that the received signal energy and the moisture content of the timber specimens show a parabolic relationship. Finally, the feasibility and reliability of the presented method, for monitoring timber moisture content, are discussed.

scholarly journals Detecting of the Longitudinal Grouting Quality in Prestressed Curved Tendon Duct Using Piezoceramic Transducers

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1212 ◽  
Author(s):  
Tianyong Jiang ◽  
Bin He ◽  
Yaowen Zhang ◽  
Lei Wang
Keyword(s):  
Lead Zirconate Titanate ◽  
Wavelet Packet ◽  
Lead Zirconate ◽  
Stress Waves ◽  
Longitudinal Plane ◽  
Power Spectral ◽  
Experimental Process ◽  
The Difference ◽  
Grouting Materials

To understand the characteristics of longitudinal grouting quality, this paper developed a stress wave-based active sensing method using piezoceramic transducers to detect longitudinal grouting quality of the prestressed curved tendon ducts. There were four lead zirconate titanate (PZT) transducers installed in the same longitudinal plane. One of them, mounted on the bottom of the curved tendon duct, was called as an actuator for generating stress waves. The other three, pasted on the top of the curved tendon duct, were called as sensors for detecting the wave responses. The experimental process was divided into five states during the grouting, which included 0%, 50%, 75%, 90%, and 100% grouting. The voltage signals, power spectral density (PSD) energy and wavelet packet energy were adopted in this research. Experimental results showed that all the amplitudes of the above analysis indicators were small before the grouting reached 90%. Only when the grouting degree reached the 100% grouting, these parameters increased significantly. The results of different longitudinal PZT sensors were mainly determined by the distance from the generator, the position of grouting holes, and the fluidity of grouting materials. These results showed the longitudinal grouting quality can be effectively evaluated by analyzing the difference between the signals received by the PZT transducers in the curved tendon duct. The devised method has certain application value in detecting the longitudinal grouting quality of prestressed curved tendon duct.

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