An initial investigation of the large strain and fatigue loading behavior of piezoelectric wafer active sensors

Doane, James; Giurgiutiu, Victor

doi:10.1117/12.599853

Cited by 7 publications

(8 citation statements)

References 8 publications

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“…The second concern addressed during the fatigue testing with PWAS was that of PWAS survivability. In previous work [19], we proved that PWAS applied to dog bone fatigue specimens with stress concentrations can survive up to the specimen failure if proper bonding methods were used. Survival beyond 12 Mcycles was thus proved [19].…”

Section: Part 1: Validation Of the Experimental Methods With Pwasmentioning

confidence: 85%

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

Giurgiutiu

Kendall

et al. 2007

AIAA Journal

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Senior Member AIAA Piezoelectric-wafer active sensors (PWAS) are small, inexpensive, non-invasive, elastic wave transmitters/receivers that can be easily affixed to a structure. PWAS are wide-band nonresonant devices that can selectively tune in various Lamb wave modes traveling in a thin-wall structure. PWAS can be wired into sensor arrays and connected to data concentrators and wireless communicators. They have the potential to bring about a revolution in structural health monitoring, damage detection, and non-destructive evaluation just as significant as ultrasonic inspection did 50 years ago. However, its development is not yet complete, and a number of issues have still to be resolved. This paper will present results obtained in using a PWAS phased array to in-situ image crack growth during a simulated structural health monitoring test. The fatigue crack growth experiment was set up on a 1000 mm by 1000 mm 2024-T3 1-mm thick aluminum plate. An initial pre-crack of 30 mm was grown under fatigue loading to a final length of 60 mm over a total of 58 kilocycles run at 10 Hz frequency in an MTS-810 testing machine. During the test, insitu readings of the PWAS phased array were taken while the testing machine was running. The PWAS were excited with a 10-Vpp smoothed 3-count tone burst of 372 kHz, which excited the symmetric S0 Lamb-wave mode. To minimize the equipment requirement to just a single channel, the excitation of the PWAS array was performed in a round robin fashion. Simultaneously, all the PWAS were in term considered as receivers. In this way, an N x N matrix of signals was collected and stored. In the beginning, the received signals were unusable due to the high 10 Hz noise superposed by the testing process. Additional hardware was constructed to pre-filter the received signals prior to digitization. Consequently, usable signals with clear crack reflections were successfully collected. The received signals were post processed with the embedded ultrasonics structural radar (EUSR) algorithm to obtain a direct imaging of the crack in the test plate (similar to the C-scan from ultrasonic NDE, only that was obtained from a single location using a sweeping beam of focused Lamb waves. The imaging results were correlated with physical measurements of the crack size using penetrating liquid and a digital camera. Remarkable consistency was obtained. Subsequently, the results were used to predict further crack growth and make a prognosis of component failure using the structural health monitoring results.

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Section: Part 1: Validation Of the Experimental Methods With Pwasmentioning

confidence: 85%

“…In previous work [19], we proved that PWAS applied to dog bone fatigue specimens with stress concentrations can survive up to the specimen failure if proper bonding methods were used. Survival beyond 12 Mcycles was thus proved [19]. In present work, we used the same bonding methods used in ref.…”

Section: Part 1: Validation Of the Experimental Methods With Pwasmentioning

confidence: 85%

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

Giurgiutiu

Kendall

et al. 2007

AIAA Journal

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“…For a bonded PWAS, The real part of the E/M impedance directly reflects the vibration spectrum of the tested specimen seen through the point-wise mechanical impedance at the point where PWAS is attached to the structure (Giurgiutiu and Zagrai, 2002). Doane and Giurgiutiu (2005) studied the behavior of PWAS transducers under large strains and under fatigue cyclic loading. To test the characteristics of the PWAS under large strain conditions, a PWAS was bonded to aircraft grade 2024-T3 aluminum alloy test specimen and subjected to tensile loading.…”

Section: Durability and Survivability Of Piezoelectric Wafer Active Smentioning

confidence: 99%

“…To test the characteristics of the PWAS under large strain conditions, a PWAS was bonded to aircraft grade 2024-T3 aluminum alloy test specimen and subjected to tensile loading. In the large strain experiments, the specimen shown in Figure 7a was used (Doane and Giurgiutiu, 2005). The specimens were fabricated from 2024 T3 aluminum with a nominal thickness of 1 mm.…”

Section: Durability and Survivability Of Piezoelectric Wafer Active Smentioning

confidence: 99%

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New Results in the Use of Piezoelectric Wafer Active Sensors for Structural Health Monitoring

Giurgiutiu

2005

46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

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Piezoelectric-wafer active sensors (PWAS) are small, inexpensive, non-invasive, elastic wave generators/receptors that can be easily affixed to a structure. Piezoelectric-wafer active sensors are wideband non-resonant devices. They can be wired into sensor arrays and connected to data concentrators and wireless communicators. However, the development of PWAS technology is not yet complete, and a number of issues have still to be resolved. This paper presents new results obtained in using the PWAS for structural health monitoring. The new results to be presented were obtained in the following directions: (i) tuning the PWAS of asymmetric geometries (rectangular plan forms) to excite and detect different Lamb wave modes in selective directions; (ii) PWAS durability and survivability; (iii) steering beam large-area coverage (embedded ultrasonic structural radar -EUSR); and probability of detection (POD) with PWAS probes (an initial investigation). The paper presents analytical methods and experimental results that can be successfully used in the design of active SHM systems to be installed on operational structures. The durability and survivability of the PWAS transducers has been tested under various environmental exposures and the importance of adequate adhesive and protective coating design has been shown. These initial results are sufficient to gain confidence in this new technology and start installation on realistic structures. (For longer-term durability and survivability results, further tests are planned in subsequent studies.) The EUSR steering beam method based on PWAS phased-arrays has been refined to increase it power of detection for various structural defects. It has been also proved that EUSR performance is not affected by structural curvature typical of aircraft installation. The initial investigation of PWAS POD has indicated that crack as small as 1.57 mm can be detected directly and imaged relatively easily. Overall, these results confirm that PWAS transducers are a technology with good potential for implementation in active SHM systems. The paper will finish with a summary of the presented work and a perspective for further research and industrial implementation.

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Durability of Structural Health Monitoring Systems under Impact Loading

Thomas

Khatibi

2017

Procedia Engineering

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An initial investigation of the large strain and fatigue loading behavior of piezoelectric wafer active sensors

Cited by 7 publications

References 8 publications

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

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

New Results in the Use of Piezoelectric Wafer Active Sensors for Structural Health Monitoring

Durability of Structural Health Monitoring Systems under Impact Loading

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