Sensor Performance Assessment Based on a Physical Model and Impedance Measurements

2013 ◽  
Vol 569-570 ◽  
pp. 751-758 ◽  
Author(s):  
Inka Buethe ◽  
Claus Peter Fritzen
Keyword(s):  
Low Cost ◽  
Embedded Sensors ◽  
Strain Gauges ◽  
Bonding Layer ◽  
Temperature Dependent ◽  
Active Sensors ◽  
Operational Conditions ◽  
Sensor Performance ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer

The employment of a large number of embedded sensors in advanced monitoring systems becomes more common, enabling in-service detection, localization and assessment of defects in mechanical, civil and aerospace structures. These sensors could be optical fibre sensors, accelerometers, strain gauges or piezoelectric wafer active sensors (PWAS). As the latter are quite popular, due to its multipurpose application as actuators and sensors and its low cost, this type will be investigated. Within this paper a possible approach of sensor performance is presented. The method uses the coupled electro-mechanical admittance to detect damage of the PWAS and its bonding layer. The help of a temperature dependent theoretical model provides for influences of changing environmental and operational conditions. The model will be compared with FEM-results, before showing the successful application on experimental results.

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.

A survey of inkjet-printed low-cost sensors

2018 ◽  
Vol 85 (7-8) ◽  
pp. 504-514
Author(s):  
Christoph Beisteiner ◽  
Bernhard G. Zagar
Keyword(s):  
Low Cost ◽  
Pressure Sensors ◽  
Strain Gauges ◽  
Temperature Dependent ◽  
Moulding Process ◽  
Seebeck Coefficients ◽  
Injection Moulding Process ◽  
Inkjet Printers ◽  
Lamination Process ◽  
Pet Films

Abstract Inkjet-printers from the company Epson and others can be used to fabricate low-cost sensors on coated PET films. By using nanoparticle-based dispersions resistive temperature dependent sensors, strain gauges, thermocouples and pressure sensors can be fabricated. For these purposes the gauge factors, Seebeck coefficients and temperature coefficients of resistance for Ag, Carbon Black and PEDOT:PSS dispersions on Mitsubishi® and Pelikan® PET substrates are characterized. Furthermore, piezoresistive effects in transverse and longitudinal strain directions are discussed. Additionally, a printed sensor system for measuring strains within a surface is presented. Finally, an injection-moulding process and a lamination process are used to improve the mechanical scratching of those sensors.

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.

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