scholarly journals Embedded Ultrasonics With Piezoelectric Wafer Active Sensors for Structural Health Monitoring of Thin-Wall Structures

Aerospace ◽  
2003 ◽  
Author(s):  
Victor Giurgiutiu
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Crack Detection ◽  
Thin Wall ◽  
Large Area ◽  
Active Sensors ◽  
Structural Health ◽  
Piezoelectric Wafer Active Sensors ◽  
Wall Structures ◽  
Pulse Echo

The capability of embedded piezoelectric water active sensors (PWAS) to perform in-situ ultrasonic nondestructive evaluation (NDE) is explored. Laboratory tests are used to prove that PWAS can satisfactorily perform Lamb wave transmission and reception. Subsequently, pulse-echo method for crack detection in an aircraft panel is illustrated. For large area scanning, a PWAS phased array is used to create the embedded ultrasonics structural radar (EUSR). In conclusion, opportunities for implementation into structural health monitoring applications and further research needs are discussed.

scholarly journals PVDF and PZT Piezoelectric Wafer Active Sensors for Structural Health Monitoring

2005 ◽  
Author(s):  
Bin Lin ◽  
Victor Giurgiutiu
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Phased Array ◽  
Lamb Waves ◽  
Experimental Results ◽  
Active Sensors ◽  
Structural Health ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer ◽  
Pulse Echo

Piezoelectric wafer active sensors (PWAS) used in structural health monitoring (SHM) applications are able to detect structural damage using Lamb waves. PWAS are small, lightweight, unobtrusive and inexpensive. PWAS achieve direct transduction between electric and elastic wave energies. PWAS are essential elements in the Lamb-wave SHM with pitch-catch, pulse-echo, phased array system and electromechanical impedance methods. PWAS are charge mode sensors and they can be used as both transmitters and receivers. A model of PWAS is shown in this paper. In vibration, impact detections applications, the PWAS response is strong due to the large dynamic change of strain. In pitch-catch, pulse-echo and phased array applications, PWAS are used to generate and receive Lamb waves and the PWAS response is small. A charge amplifier for PWAS applications is introduced in this paper. PWAS are normally made of piezoceramic Lead Zirconate Titanate (PZT). The structural integrity tests require attachment of PWAS to the material surface and there are critical applications where the rigid piezoceramic wafers cannot conform to curved surfaces. As alternative one can use flexible piezopolymer such as polyvinylidene fluoride (PVDF); such PVDF-PWAS have been studied in this paper. PVDF-PWAS were mounted on a cantilever beam for the free vibration test and on a long rod for the longitudinal impact test. The experimental results of the PZT-PWAS and PVDF-PWAS have been compared with the conventional strain gauge. The theoretical and experimental results in this study gave the basic demonstration of the piezoelectricity of PZT-PWAS and PVDF-PWAS.

Impact Detection Using an Array of Piezoelectric Wafer Active Sensors and a Microcontroller Unit

2010 ◽  
Author(s):  
Abraham Light-Marquez ◽  
Andrei Zagrai
Keyword(s):  
Structural Health Monitoring ◽  
Sensor Network ◽  
Health Monitoring ◽  
Detection System ◽  
Active Sensors ◽  
Structural Health ◽  
Impact Detection ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer ◽  
The Impact

This report discusses the development of an embeddable impact detection system utilizing an array of piezoelectric wafer active sensors (PWAS) and a microcontroller. Embeddable systems are a critical component to successfully implement a complete and robust structural health monitoring system. System capabilities include impact detection, impact location determination and digitization of the impact waveform. A custom algorithm was developed to locate the site of the impact.. The embedded system has the potential for additional capabilities including advanced signal processing and the integration of wireless functionality. For structural health monitoring applications it is essential to determine the extent of damage done to the structure. In an attempt to determine these parameters a series of impact tests were conducted using a ball drop tower on a square aluminum plate. The response of the plate to the impact event was recorded using a piezoelectric wafer sensor network attached to the surface of the plate. From this testing it was determined that several of the impact parameters are directly correlated with the features recorded by the sensor network.

scholarly journals Piezoelectric Wafer Active Sensors for Structural Health Monitoring of Composite Structures Using Tuned Guided Waves

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Victor Giurgiutiu
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Composite Structures ◽  
Guided Waves ◽  
Guided Wave ◽  
Impedance Method ◽  
Active Sensors ◽  
Structural Health ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer

Piezoelectric wafer active sensors (PWAS) are lightweight and inexpensive transducers that enable a large class of structural health monitoring (SHM) applications such as: (a) embedded guided wave ultrasonics, i.e., pitch-catch, pulse-echo, phased arrays; (b) high-frequency modal sensing, i.e., the electro-mechanical (E/M) impedance method; and (c) passive detection (acoustic emission and impact detection). The focus of this paper is on the challenges posed by using PWAS transducers in the composite structures as different from the metallic structures on which this methodology was initially developed. After a brief introduction, the paper reviews the PWAS-based SHM principles. It follows with a discussion of guided wave propagation in composites and PWAS tuning effects. Then, it discusses damage modes in composites. Finally, the paper presents some experimental results with damage detection in composite specimens. Hole damage and impact damage were detected using pitch-catch method with tuned guided waves being sent between a transmitter PWAS and a received PWAS. Root mean square deviation (RMSD) damage index (DI) were shown to correlate well with hole size and impact intensity. The paper ends with summary and conclusion; suggestions for further work are also presented.

Computational Setup of Structural Health Monitoring for Real-Time Thermal Verification

2011 ◽  
Author(s):  
Derek Doyle ◽  
Whitney Reynolds ◽  
Brandon Arritt ◽  
Brenton Taft
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Structural Changes ◽  
Space Vehicles ◽  
Lap Joint ◽  
Active Sensors ◽  
Structural Health ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer ◽  
Inspection Techniques

Research at the AFRL Space Vehicles Directorate is being conducted to reduce schedule times for assembly, integration, and test, to make satellite-based capabilities more responsive to user needs. Structural Health Monitoring has been pursued as a means for validating workmanship and has been proven on PnPSat-1. Embedded ultrasonic piezoelectric wafer active sensors (PWAS) have been utilized with local and global inspection techniques, developed both in house and by collaborating universities, to detect structural changes that may occur during assembly, integration, and test. Specific attention has focused on interface qualification. It is now reasonable to believe that evaluation of interfaces through the use of such sensors can also be used to indirectly qualify the structure thermally and that tedious thermal-vacuum testing may be truncated or eliminated altogether. This paper focuses on the computational development of extracting thermal properties from ultrasonic transmission records. Methods are validated on simple bolted lap-joint cantilever beams.

Sign in / Sign up

Export Citation Format

Share Document