scholarly journals In-Situ Imaging of Crack Growth with Piezoelectric Wafer Active Sensors

2006 ◽  
Author(s):  
Victor Giurgiutiu ◽  
Christopher Jenkins ◽  
James Kendall ◽  
Lingyu Yu
Keyword(s):  
Crack Growth ◽  
Active Sensors ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer ◽  
In Situ Imaging

scholarly journals In-Situ Imaging of Crack Growth with Piezoelectric-Wafer Active Sensors

AIAA Journal ◽  
2007 ◽  
Vol 45 (11) ◽  
pp. 2758-2769 ◽  
Author(s):  
Victor Giurgiutiu ◽  
Lingyu Yu ◽  
James R. Kendall ◽  
Christopher Jenkins
Keyword(s):  
Crack Growth ◽  
Active Sensors ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer ◽  
In Situ Imaging

scholarly journals In-Situ Multi-Mode Sensing With Embedded Piezoelectric Wafer Active Sensors for Critical Pipeline Health Monitoring

2007 ◽  
Author(s):  
Lingyu Yu ◽  
Victor Giurgiutiu ◽  
Yuh Chao ◽  
Patrick Pollock
Keyword(s):  
Damage Detection ◽  
Time Data ◽  
Active Sensors ◽  
Flowing Fluid ◽  
Electromechanical Impedance ◽  
Corrosion Detection ◽  
Piezoelectric Wafer Active Sensors ◽  
Pipeline Systems ◽  
Piezoelectric Wafer

Pipelines are important infrastructures in petroleum and gas industries which are vital to the national economy. They are typically subjected to corrosion inside of the pipe and there is an urgent need for the development of a cost-effective, non-excavating, in-service, permanent critical pipeline damage detection and prediction system. In this paper, we proposed an in-situ multiple mode pipeline monitoring system by utilizing permanently installed piezoelectric wafer active sensors (PWAS). As an active sensing device, PWAS can be bonded to the structure or inserted into a composite structure, operated in propagating wave mode or electromechanical impedance mode. The small size and low cost (about ∼$10 each) make it a potential and unique technology for in-situ application. Additionally, PWAS transducers can operate at a temperature as high as 260°C which is sufficient for most critical pipeline systems used in gas/petroleum industry. This system can be used during in-service period, recording and monitoring the changes, such as cracks, impedance, wall thickness, etc., of the pipelines over time. Having the real-time data available, maintenance strategies based on these data can then be developed to ensure a safe and less expensive operation of the pipeline systems. The paper will first give an intensive literature review of current pipeline corrosion detection. Then, the basic principles of applying PWAS to in-situ SHM using in-plane propagation waves and impedance measurement for damage detection are studied and developed. Next, experiments were conducted to verify the corrosion detection and thickness measurement ability of PWAS sensor network in a laboratory setting and in water pipe with flowing fluid inside as well. In addition, the potential of PWAS application for high temperature pipeline thickness monitoring was also investigated.

scholarly journals In-Situ Fabrication of Composite Piezoelectric Wafer Active Sensors for Structural Health Monitoring

Aerospace ◽  
2004 ◽  
Author(s):  
Victor Giurgiutiu ◽  
Bin Lin
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Piezoelectric Composite ◽  
Active Sensors ◽  
In Situ Composite ◽  
Structural Health ◽  
Piezoelectric Wafer Active Sensors ◽  
In Situ Fabrication ◽  
Piezoelectric Wafer

Structural health monitoring (SHM) is important for reducing maintenance costs while increasing safety and reliability. Traditionally, structural integrity tests required attachment of sensors to the material surface. This is often a burdensome and time-consuming task, especially considering the size and magnitude of the surfaces measured (such as aircraft, bridges, structural supports, etc.). Temporary sensors are a hassle to install; there are some critical applications where they simply cannot accomplish the task required. Piezoelectric wafer active sensors (PWAS) can be permanently attached to the structure and offer a permanent sensor solution. Existing ceramic PWAS, while fairly accurate when attached correctly to the substance, may not provide the long term durability required for SHM. The bonded interface between the PWAS and the structure is often the durability weak link. Better durability may be obtained from a built-in sensor that is incorporated into the material. This paper describes the work on the in-situ fabrication of PWAS using a piezoelectric composite approach. The piezoelectric composite was prepared by mixing small lead zirconate titanate (PZT) particles in an epoxy resin matrix; the mixture was then directly applied onto the surface of a host structure using a designed mask. The curing of the piezo composite was carried out at elevated temperature. After curing, the cured composite was sanded down to the desired thickness. Finally, the piezo composite was poled under a high electric field to activate the piezoelectric effect. The resulting in-situ composite PWAS was utilized as a sensor for dynamic vibration and impact. Characterization of the in-situ composite PWAS on aluminum structure have been recorded and compared with ceramic PWAS before and after polarization. To evaluate the performance of the in-situ composite PWAS, both vibration and impact tests were conducted. In-situ composite PWAS are believed to be a good candidate for reliable low-cost sensor fabrication for SHM.

scholarly journals Modeling and Experimentation of Thickness Mode E/M Impedance and Rayleigh Wave Propagation for Piezoelectric Wafer Active Sensors on Thick Plates

2014 ◽  
Author(s):  
Tuncay Kamas ◽  
Victor Giurgiutiu ◽  
Bin Lin
Keyword(s):  
Rayleigh Wave ◽  
High Frequency ◽  
Rayleigh Waves ◽  
Wave Mode ◽  
Elastic Plates ◽  
Active Sensors ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer ◽  
Thickness Mode

This paper discusses theoretical and experimental analyses of the standing harmonic waves through the electro-mechanical impedance spectroscopy (EMIS) and guided surface acoustic waves (SAW) through the guided wave propagation (GWP) analyses. Both EMIS and GWP analyses have been carried out by utilizing piezoelectric wafer active sensors (PWAS) for in situ structural inspection. PWAS has recently been extensively employed in many applications such as nuclear-structural as well as aero-structural health monitoring and non-destructive evaluations (NDE). EMIS method is utilized for high frequency local modal sensing to determine the dynamic characteristics of PWAS bonded on nuclear-structural component for in-situ ultrasonics. Rayleigh waves a.k.a., SAW, were generated in relatively thick isotropic elastic plates. Rayleigh waves have the property of propagating close to the plate surface, with rapid attenuation with depth. The polarization of Rayleigh waves lies in a plane perpendicular to the surface so that the effective penetration depth is less than a wavelength. Rayleigh waves are a high frequency approximation of the first symmetric (S0) and anti-symmetric (A0) Lamb wave modes. As the frequency becomes very high the S0 and the A0 wave speeds coalesce, and both have the same value. This value is exactly the Rayleigh wave speed and becomes constant along the frequency. In the first part of the study, simplified theoretical constrained PWAS-EMIS model is briefly discussed in relatively high frequency range (in MHz order of magnitude) in terms of thickness mode. Analytical predictive thickness mode impedance simulations of PWAS bonded on plate-like host structures are presented in corresponding with the experiments. For the experimental analyses, PWAS transducers are affixed on isotropic elastic plates such as aluminum plate in relatively high thickness and on a rail I-beam. The extent of the agreement between the experimental and analytical EMIS analyses of PWAS in thickness mode is presented. The study is followed with GWP tests through the pitch-catch method. Rayleigh wave signal packets which are generated in the relatively thick plate and a rail I-beam in high frequency region are assessed along with the experimental thickness mode PWAS-EMIS results. The tuning curve of Rayleigh wave is determined to show the tuning effect of the structure thickness on producing a dominant Rayleigh wave mode. The significant usage of the tuned Rayleigh wave mode is essentially discussed for the applications in the in-situ inspection of relatively thick structures such as nuclear power plant structures. The paper ends with summary, conclusions and suggestions for future work.

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