scholarly journals Influence of Sensor Statistics on Piezoelectric and Magneto-Elastic Damage Detection

2012 ◽  
Author(s):  
David Conrad ◽  
Andrei Zagrai ◽  
Daniel Meisner
Keyword(s):  
Damage Detection ◽  
Mechanical Impedance ◽  
Active Sensors ◽  
Structural Dynamic ◽  
Detection Scheme ◽  
Piezoelectric Wafer Active Sensors ◽  
Impedance Response ◽  
Piezoelectric Wafer ◽  
Pulse Echo ◽  
The Impact

Increasing complexity of aerospace structures facilitates a growing need for structural health monitoring (SHM) systems capable of real-time active damage detection. A variety of sensing approaches have been demonstrated using embedded ultrasonic sensors such as piezoelectric wafer active sensors (PWAS) and magneto-elastic active sensors (MEAS). Common methodologies consider wave propagation (pitch-catch or pulse-echo) and standing wave (vibration or impedance) techniques with damage detection capabilities dependent upon structural geometry, material characteristics, distance to damage and damage size/orientation. While recent studies have employed damage detection and classification approaches that are dependent on cumulative statistics, this study explores the contribution of sensor parameters and experimental setup variability on the damage detection scheme. The impact of variability in PWAS and MEAS are considered on sensor use in ultrasonic and magneto-mechanical impedance damage detection. In order to isolate sensor parameters, measurements were conducted with PWAS in free-free boundary conditions. Variability of PWAS parameters was evaluated by measuring the sensors impedance response. An analytical model of PWAS was used to estimate sensor parameters and to determine their variability. Additionally, experiments using MEAS were performed that demonstrate variation of magneto-mechanical impedance during structural dynamic tests. From these experiments the importance of sensor setup is discussed and its contribution into the overall detection scheme is explored.

scholarly journals Non-Destructive Evaluation (NDE) of Space Application Panels Using Piezoelectric Wafer Active Sensors

2005 ◽  
Author(s):  
Adrian Cuc ◽  
Zeb Tidwell ◽  
Victor Giurgiutiu ◽  
Shiv Joshi
Keyword(s):  
Damage Detection ◽  
Complex Geometry ◽  
Lamb Waves ◽  
Mechanical Impedance ◽  
Impedance Method ◽  
Active Sensors ◽  
Space Applications ◽  
Piezoelectric Wafer Active Sensors ◽  
Investigation Methods ◽  
Piezoelectric Wafer

Ultrasonic guided waves inspection using Lamb waves is suitable for damage detection in metallic structures. This paper will present experimental results obtained using guided Lamb waves to detect flaws in aluminum specimens with design features applicable to space applications. Two aluminum panels were fabricated from a variable-thickness aluminum top plate, with two bolted I-beams edge stiffeners and four bonded angle stiffeners. Artificial damages were introduced in the two panels: cracks, corrosions, and disbonds. The proposed investigation methods used embedded piezoelectric wafer active sensors (PWAS) to excite and receive Lamb waves. Three wave propagation methods were used: pitch-catch, pulse-echo, and the embedded ultrasonic structural radar (EUSR). In addition, we also used a standing-wave damage detection technique, the electro-mechanical impedance method. The paper will present in detail the salient results from using these methods for damage detection and structural health monitoring. Where appropriate, comparison between different methods in detecting the same damage will be performed. The results have demonstrated the ability of piezoelectric wafer active sensors working in conjunction with guided Lamb waves to detect various types of damages present in complex geometry structures typical of space applications.

Impact Localization on a Composite Plate With Unknown Material Properties Using PWAS Transducers and Wavelet Transform

2017 ◽  
Author(s):  
Asaad Migot ◽  
Victor Giurgiutiu
Keyword(s):  
Wavelet Transform ◽  
Nonlinear Equations ◽  
Material Properties ◽  
Composite Plate ◽  
Linear Equations ◽  
Active Sensors ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer ◽  
The Impact ◽  
Impact Localization

In this work, an impact experiment on a composite plate with unknown material properties (its group velocity profile is unknown) is implemented to localize the impact points. A pencil lead break is used to generate acoustic emission (AE) signals which are acquired by six piezoelectric wafer active sensors (PWAS). These sensors are distributed with a particular configuration in two clusters on the plate. The time of flight (TOF) of acquired signals is estimated at the starting points of these signals. The continuous wavelet transform (CWT) of received signals are calculated with AGU Vallen wavelet program to get the accurate values of the TOF of these signals. Two methods are used for determining the coordinates of impact points (localization the impact point). The first method is the new technique (method 1) by Kundu. This technique has two linear equations with two unknowns (the coordinate of AE source point). The second method is the nonlinear algorithm (method 2). This algorithm has a set of six nonlinear equations with five unknowns. Two MATLAB codes are implemented separately to solve the linear and nonlinear equations. The results show good indications for the location of impact points in both methods. The location errors of calculated impact points are divided by constant distance to get independent percentage errors with the site of the coordinate.

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.

Guided wave propagation in composite laminates using piezoelectric wafer active sensors

2013 ◽  
Vol 117 (1196) ◽  
pp. 971-995 ◽  
Author(s):  
M. Gresil ◽  
V. Giurgiutiu
Keyword(s):  
Wave Propagation ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Mechanical Impedance ◽  
Guided Wave ◽  
Impedance Method ◽  
Active Sensors ◽  
Piezoelectric Wafer Active Sensors ◽  
Guided Wave Propagation ◽  
Piezoelectric Wafer

AbstractPiezoelectric 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., electro-mechanical impedance method; and (c) passive detection. The focus of this paper is on the challenges posed by using PWAS transducers in the composite laminate 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, the mechanical effect is discussed on the integration of piezoelectric wafer inside the laminate using a compression after impact. Experiments were performed on a glass fibre laminate, employing PWAS to measure the attenuation coefficient. Finally, the paper presents some experimental and multi-physics finite element method (MP-FEM) results on guided wave propagation in composite laminate specimens.

Detection of Cracks Using Piezoelectric Wafer Active Sensors

2005 ◽  
Vol 293-294 ◽  
pp. 201-206
Author(s):  
Antoni Blazewicz ◽  
Andrei G. Kotousov ◽  
Frank Wornle
Keyword(s):  
Laboratory Tests ◽  
Crack Detection ◽  
Fatigue Loading ◽  
Structural Elements ◽  
Active Sensors ◽  
Sensor Applications ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer ◽  
Pulse Echo ◽  
Pulse Echo Method

The capability of piezoelectric wafer active sensors to identifying cracks which are common to metallic structural elements subjected to fatigue loading were explored. A number of laboratory tests were performed to investigate Lamb wave transmission and reception characteristics as well as the sensitivity of the transmitted and reflected signals to the presence of a through-the-thickness crack of various length and orientation in a thin plate. Based on the laboratory tests an optimum strategy for crack detection with the pulse-echo method was investigated. The method can be used for large areas scanning with a small amount of sensors and is favoured for embedded and leave-in-place sensor applications.

Sign in / Sign up

Export Citation Format

Share Document