scholarly journals Tension Monitoring of Wedge Connection Using Piezoceramic Transducers and Wavelet Packet Analysis Method

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 364
Author(s):  
Xiaoyu Zhang ◽  
Liuyu Zhang ◽  
Laijun Liu ◽  
Linsheng Huo
Keyword(s):  
Energy Transfer ◽  
Stress Wave ◽  
Wavelet Packet ◽  
Active Sensing ◽  
Analysis Method ◽  
Wavelet Packet Analysis ◽  
Monitoring Method ◽  
Anchorage System ◽  
Steel Strand ◽  
Contact Surfaces

A steel strand is widely used in long span prestressed concrete bridges. The safety and stability of a steel strand are important issues during its operation period. A steel strand is usually subjected to various types of prestress loss which loosens the anchorage system, negatively impacting the stability of the structure and even leading to severe accidents. In this paper, the authors propose a wavelet packet analysis method to monitor the looseness of the wedge anchorage system by using stress wave-based active sensing. As a commonly used piezoceramic material, lead zirconate titanate (PZT) is employed with a strong piezoelectric effect. In the proposed active sensing approach, PZT patches are used as sensors and actuators to monitor the steel strand looseness. The anchorage system consists of the steel strand, wedges and barrel, which forms two different direct contact surfaces to monitor the tension force. PZT patches are pasted on the surface of each steel strand, corresponding wedge and barrel, respectively. Different combinations of PZTs are formed to monitor the anchoring state of the steel strand according to the position of the PZT patches. In this monitoring method of two contact surfaces, one PZT patch is used as an actuator to generate a stress wave and the other corresponding PZT patch is used as a sensor to detect the propagated waves through the wedge anchorage system. The function of these two PZTs were exchanged with the changing of transmission direction. The wavelet packet analysis method is utilized to analyze the transmitted signal between PZT patches through the steel strand anchorage system. Compared with the wavelet packet energy of received signals under different PZT combinations, it could be found that the wavelet packet energy increased with the increasing of anchorage system tightness. Therefore, the wavelet packet energy of received signal could be used to monitor the tightness of the steel strand during operation. Additionally, the wavelet packet energy of the received signals are different when the same PZT combination exchanges the energy transfer direction. With the comparison on the received signals of different combinations of PZTs, the optimal energy transfer path corresponding to different contact surfaces of the steel strand could be determined and the optimal experimental results are achieved.

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 Debonding Performance of CFRP-Strengthened Nanomaterial Concrete Beam Using Wavelet Packet Analysis

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yang Liu ◽  
Ming Zhang ◽  
Xinfeng Yin ◽  
Zhou Huang ◽  
Lei Wang
Keyword(s):  
Stress Wave ◽  
Concrete Beam ◽  
Wavelet Packet ◽  
Frequency Domain Analysis ◽  
Interfacial Debonding ◽  
Wavelet Packet Analysis ◽  
Loading Test ◽  
Periodic Loading ◽  
Reinforced Polymer ◽  
Starting Point

The carbon fiber reinforced polymer- (CFRP-) strengthened nanomaterial concrete beam (SNCB) has been increasingly attracting a widespread attention because of the advantages of using the excellent properties of nanomaterials to improve structural properties. An active sensing approach based on a piezoceramic transducer is developed to detect the interfacial debonding performance of CFRP-SNCB. A CFRP-SNCB specimen was fabricated and subjected to periodic loading test to initiate the debonding damage. Three piezoceramic smart aggregates (SAs) and three piezoceramic smart nanomaterial aggregates (SNAs) are embedded in the specimen and used as an actuator and sensor. Experiments show that the nanomaterial concrete becomes a good conduit for wave propagation due to the nucleation and filling effect of nanomaterial. The stress wave signal caused by the embedded SNAs is more sensitive to the debonding performance between CFRP and concrete than SA. The attenuation of stress wave caused by the increase of the severity of debonding damage can be clearly observed from the signals received from SAs and SNAs in the frequency domain analysis. The debonding cracking of the tension end region is earlier than the bond end region, which proves the starting point of structural debonding damage. Furthermore, the debonding state can be evaluated by wavelet packet analysis. The research results demonstrate that the proposed method has potentials to detect the interfacial debonding performance of CFRP-SNCB.

scholarly journals Health Status Monitoring of Cuplock Scaffold Joint Connection Based on Wavelet Packet Analysis

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Liuyu Zhang ◽  
Chenyu Wang ◽  
Gangbing Song
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Wavelet Packet ◽  
Experimental Results ◽  
Wavelet Packet Analysis ◽  
Monitoring Method ◽  
Structural Health ◽  
Index Matrix ◽  
Joint Connection ◽  
The Stability

The cuplock scaffolds are widely used as a temporary facility in the bridge and other constructions. The looseness of cuplock scaffold connection plays a significant role in the stability of the structure. Contemporary structural health monitoring method is reviewed in this paper at first, and then we proposed wavelet packet analysis based method. In order to detect the looseness of cuplock connection, three stress PZTs and three shear PZTs used as transducers are mounted onto vertical bar and cross bars of cuplok scaffold. Wavelet packet analysis is applied to analyze the transmitted signal energy between two PZTs through cuplok connection. Experimental results show that shear PZT has better performance than stress PZT to be used as actuator and sensor for the wavelet packet analysis based structural health monitoring. Besides, a sensor looseness index matrix (SLIM) is derived to indicate the looseness of the cuplock connection. The experimental results show that looseness index increases as the connection gets loose.

scholarly journals Experimental study of grout defect identification in precast column based on wavelet packet analysis

2019 ◽  
Vol 15 (11) ◽  
pp. 155014771988959
Author(s):  
Xuan Zhang ◽  
Deyuan Zhou ◽  
Hesheng Tang ◽  
Xiao Han
Keyword(s):  
Energy Transfer ◽  
Energy Spectrum ◽  
Wavelet Packet ◽  
Precast Concrete ◽  
Energy Ratio ◽  
Combination Method ◽  
Wavelet Packet Analysis ◽  
Average Deviation ◽  
Defect Identification ◽  
Ratio Variation

Grout defects always exist in sleeves of precast structures, but studies on grout defect identification are rarely performed. This article proposes a combination method of dynamic excitation technique and wavelet packet analysis for sleeve defect identification in the precast structure. Hammer excitation on a 1/2-scaled two-floor precast concrete frame structure with column rebar splicing by grout sleeves is conducted to collect column acceleration responses. Moreover, the corresponding energy spectrum is obtained by the wavelet packet analysis. Furthermore, three defect identification indices, that is, percentage of energy transfer, energy ratio variation deviation, and energy spectrum average deviation, are calculated and compared. Robustness analysis of the energy ratio variation deviation is carried out by adding white noise in the original acceleration response signals. The results show that (1) the percentage of energy transfer, the energy ratio variation deviation, and the energy spectrum average deviation are positively correlated with the grout defect degree where the energy ratio variation deviation is more sensitive in the identification of defects; (2) the energy ratio variation deviation robustness of the original signal with the inputted multiplicative white Gaussian noises is better than that with the inputted additive white Gaussian noise; and (3) the proposed defect identification method can characterize the sleeve grout defect degree in column.

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 Experimental Research on Shear Failure Monitoring of Composite Rocks Using Piezoelectric Active Sensing Approach

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1376 ◽  
Author(s):  
Yang Liu ◽  
Yicheng Ye ◽  
Qihu Wang ◽  
Weiqi Wang
Keyword(s):  
Shear Failure ◽  
Wavelet Packet ◽  
Failure Process ◽  
Damage Index ◽  
Active Sensing ◽  
Wavelet Packet Analysis ◽  
Engineering Structures ◽  
Damage Indices ◽  
Monitoring Test ◽  
Failure Monitoring

Underground space engineering structures are generally subject to extensive damages and significant deformation. Given that composite rocks are prone to shear failure, which cannot be accurately monitored, the piezoelectric active sensing method and wavelet packet analysis method were employed to conduct a shear failure monitoring test on composite rocks in this study. For the experiment, specimens were prepared for the simulation of the composite rocks using cement. Two pairs of piezoelectric smart aggregates (SAs) were embedded in the composite specimens. When the specimens were tested using the direct shear apparatus, an active sensing-based monitoring test was conducted using the embedded SAs. Moreover, a wavelet packet analysis was conducted to compute the energy of the monitoring signal; thus allowing for the determination of the shear damage index of the composite specimens and the quantitative characterization of the shear failure process. The results indicated that upon the shear failure of the composite specimens, the amplitudes and peak values of the monitoring signals decreased significantly, and the shear failure and damage indices of the composite specimens increased abruptly and approached a value of 1. The feasibility and reliability of the piezoelectric active sensing method, with respect to the monitoring of the shear failure of composite rocks, was therefore experimentally demonstrated in this study.

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.

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