An Approach for Measuring Quasi-Static Mechanical Loads Using a Low-Power Piezoelectric Sensor

2012 ◽  
Author(s):  
John A. Vine ◽  
Scott D. Moss
Keyword(s):  
Low Power ◽  
Electrical Impedance ◽  
Mechanical Load ◽  
Fiber Composite ◽  
Piezoelectric Sensor ◽  
Potential Method ◽  
Strain Sensors ◽  
Piezoelectric Transducers ◽  
Dynamic Strain ◽  
Static Mechanical

The Australian Defence Science and Technology Organisation (DSTO) is developing Structural Health Monitoring (SHM) approaches for use on air vehicles. This work describes a potential method for measuring quasi-static strains by monitoring the mechanical-load induced capacitive changes in a piezoelectric sensor. This approach may be combined with the well-documented capability of piezoelectric material to measure dynamic-strain, and may hence allow piezoelectric transducers to be used as low-power, single-solution strain sensors. DSTO has experimentally confirmed that the electrical impedance of a Macro Fiber Composite (MFC) piezoelectric transducer changes with varying strain. In particular, a sensitivity of 1.7 mΩ per με has been observed. With accurate transducer modelling, these changes could be used as an indication of the quasi-static strain in the underlying vehicular structure.

scholarly journals Ultra-Low Power CMOS Readout for Resonant MEMS Strain Sensors

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 973
Author(s):  
Marco Crescentini ◽  
Cinzia Tamburini ◽  
Luca Belsito ◽  
Aldo Romani ◽  
Alberto Roncaglia ◽  
...  
Keyword(s):  
Low Power ◽  
Power Supply ◽  
First Generation ◽  
Negative Resistance ◽  
Low Noise ◽  
Strain Sensors ◽  
Current Conveyors ◽  
Ultra Low Power ◽  
Active Elements ◽  
Low Power Cmos

This paper presents an ultra-low power, silicon-integrated readout for resonant MEMS strain sensors. The analogue readout implements a negative-resistance amplifier based on first-generation current conveyors (CCI) that, thanks to the reduced number of active elements, targets both low-power and low-noise. A prototype of the circuit was implemented in a 0.18-µm technology occupying less than 0.4 mm2 and consuming only 9 µA from the 1.8-V power supply. The prototype was earliest tested by connecting it to a resonant MEMS strain resonator.

Flexible strain sensors fabricated with carbon nano-tube and carbon nano-fiber composite thin films

2010 ◽  
Vol 518 (24) ◽  
pp. 7343-7347 ◽  
Author(s):  
Fuh-Yu Chang ◽  
Ruoh-Huey Wang ◽  
Hsiharng Yang ◽  
Yu-Hsien Lin ◽  
Tse-Min Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Fiber Composite ◽  
Strain Sensors ◽  
Composite Thin Films ◽  
Nano Fiber ◽  
Carbon Nano Tube

Low-power electrical impedance tomography spectroscopy

2019 ◽  
Vol 38 (5) ◽  
pp. 1480-1492 ◽  
Author(s):  
Juliana Padilha Leitzke ◽  
Hubert Zangl
Keyword(s):  
Computational Complexity ◽  
Low Power ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Mean Squared Error ◽  
Order Approximation ◽  
Electrode Design ◽  
Electrode Geometry ◽  
Impedance Tomography ◽  
Content Type

Purpose This paper aims to present an approach based on electrical impedance tomography spectroscopy (EITS) for the determination of water and ice fraction in low-power applications such as autarkic wireless sensors, which require a low computational complexity reconstruction approach and a low number of electrodes. This paper also investigates how the electrode design can affect the reconstruction results in tomography. Design/methodology/approach EITS is performed by using a non-iterative method called optimal first order approximation. In addition to that, a planar electrode geometry is used instead of the traditional circular electrode geometry. Such a structure allows the system to identify materials placed on the region above the sensor, which do not need to be confined in a pipe. For the optimization, the mean squared error (MSE) between the reference images and the obtained reconstructed images was calculated. Findings The authors demonstrate that even with a low number of four electrodes and a low complexity reconstruction algorithm, a reasonable reconstruction of water and ice fractions is possible. Furthermore, it is shown that an optimal distribution of the sensor electrodes can help to reduce the MSE without any costs in terms of computational complexity or power consumption. Originality/value This paper shows through simulations that the reconstruction of ice and water mixtures is possible and that the electrode design is a topic of great importance, as they can significantly affect the reconstruction results.

scholarly journals Low-Cost Piezoelectric Sensor Characterization for Energy Harvesting Applications

Proceedings ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 25
Author(s):  
Paulo Afonso Ferreira Junior ◽  
Fernando de Souza Campos ◽  
Bruno Albuquerque de Castro ◽  
José Alfredo Covolan Ulson ◽  
Fabrício Guimarães Baptista ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Low Cost ◽  
Electrical Power ◽  
Electric Energy ◽  
Piezoelectric Sensor ◽  
Energy Conversion Efficiency ◽  
Piezoelectric Transducers ◽  
Maximum Power ◽  
Sensor Nodes ◽  
Resistive Load

Energy harvesting engineering fields constitutes a promising area to provide electrical power for low-power electric applications obtained from other sources of energy available in the environment such as thermal, electromagnetic, vibrational and acoustic by using transducers. Vibrational sources stand out as a main alternative to be used for generating electric power in sensor nodes in microelectronic devices due to the greater energy conversion efficiency and the use of a simple structure. The cantilever is the main system implemented in studies of obtaining electric energy from vibrations using piezoelectric transducers. Most of piezoelectric transducers in the literature are not yet commercially available and/or are difficult to access for purchase and use. This paper proposes the characterization of low-cost piezoelectric transducers, configured as sensors, for Energy Harvesting applications using three different sizes of circular piezoelectric transducers (PZTs.) with diameters of 3.4 cm, 2.6 cm and 1.5 cm. For all three different PZTs, it was found that the maximum power transfer occurs for a resistive load of 82 kΏ. The maximum power generated in the load for the three PZTs was 40 uW, 14 uW and 1.4 W; with RMS voltages of 2.8 V, 2.10 V and 0.6 V; an acceleration of 1.3 g and a vibration frequency approximate of 7 Hz.

scholarly journals Study of a Low-Cost Piezoelectric Sensor for Three Phase Induction Motor Load Estimation

Proceedings ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 46 ◽  
Author(s):  
Guilherme B. Lucas ◽  
Bruno A. de Castro ◽  
Marco A. Rocha ◽  
Andre L. Andreoli
Keyword(s):  
Mechanical Load ◽  
Low Cost ◽  
Failure Detection ◽  
Piezoelectric Sensor ◽  
Industrial Applications ◽  
Load Estimation ◽  
Alternative Approach ◽  
Three Phase ◽  
High Level ◽  
Induction Motor Load

Due the complexity of control and automation networks in modern industries, sensor-based systems stand out as effective approaches for failure detection in electrical and mechanical machines. This kind of intervention has a high operational value in industrial scenarios, once it can avoid corrective maintenance stops, i.e., before the failure reaches a high level of severity and compromises the machine. Consequently, the development of sensors applied to non-destructive techniques (NDT) for failure monitoring in electrical machines has become a recurrent theme in recent studies. In this context, this paper investigates the application of low-cost piezoelectric sensors for vibration analysis, which is an NDT that has already proved to be efficient for the detection of many structural anomalies in induction motors. Further, the proposed work presents a low-cost alternative approach for expensive commercial sensors, which will make this NDT more attractive for industrial applications. To describe the piezoelectric sensor frequency response, a pencil lead break (PLB) test was performed. After this validation, the Root Mean Square (RMS) value from the voltage samples obtained in the test bench was used as a signal processing method. A comparison between the results for different levels of mechanical load attached to the machine shaft indicated not only the successful performance of the low-cost sensors for load estimation purposes, but also showed that oversized motors may present higher vibration levels in some components that could cause mechanical wearing.

A Study on the Effects of Strain Rates on Characteristics of Brain Tissue

2017 ◽  
Author(s):  
Mohammad Hosseini Farid ◽  
Ashkan Eslaminejad ◽  
Mariusz Ziejewski ◽  
Ghodrat Karami
Keyword(s):  
Strain Rate ◽  
Brain Tissue ◽  
Mechanical Load ◽  
Experimental Studies ◽  
High Rate ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Compression Tests ◽  
Static Strain ◽  
The Brain

Traumatic brain injury (TBI) often happens when the brain tissue undergoes a high rate mechanical load. Although numerous research works have been carried out to study the mechanical characterization of brain matter under quasi-static (strain rate ≤ 100 S−1) loading but a limited amount of experimental studies are available for brain tissue behavior under dynamic strain rates (strain rate ≥ 100 S−1). In this paper, the results of a study on mechanical properties of ovine brain tissue under unconfined compression tests are to be presented. The samples were compressed under uniaxial strain rates of 0.0667, 3.33, 6.667, 33.33, 66.667 and 200 S−1. The brain tissue presents a stiffer response with increasing strain rate, showing a time-dependent behavior. So the hyperelastic-only models are not adequate to exhibit the brain viscoelasticity. Therefore, two hyper-viscoelastic constitutive equations based on power function model and Mooney-Rivlin energy function are applied to the results with quasi-static strain rate (≤ 100 S−1). Good agreement of experimental and theoretical has been achieved for results of the low strain rates. It is concluded that the obtained material parameters from quasi-static tests are not appropriate enough to fit the result with the high strain rate of 200 S−1. The study will further provide new insight into a better understanding of the rate-dependency behavior of the brain tissue under dynamic conditions. This is essential in the development of constitutive material characteristics for an efficient human brain finite element models to predict TBI under impact condition or high motion.

Advanced Ferroelectric MFC Actuators: The Effect of Ferro-Elastic Domain Switching

2008 ◽  
Author(s):  
Uri Kushnir ◽  
Oded Rabinovitch
Keyword(s):  
Nonlinear Response ◽  
Domain Switching ◽  
Mechanical Load ◽  
Fiber Composite ◽  
Beam Element ◽  
Mechanical Loads ◽  
Active Structure ◽  
Elastic Domain ◽  
Macro Fiber Composite ◽  
Fiber Segment

Macro Fiber Composite (MFC) actuators, which are commonly integrated in modern smart structures, may be subjected to high levels of mechanical loads. Opposed to the electrical actuation, these loads are not always controlled or anticipated by the user. Thus, they may yield a response that is beyond the linear range due to a stress induced ferro-elastic domain switching. In this paper, the phenomenon of domain switching and mechanical depolarization in the MFC actuator and the resulting degradation of the actuation capabilities are investigated. As an illustrative numerical example, the response of MFC layers in an active beam element is analyzed. Emphasis is placed on the location of the fiber segment along the active beam with a distinction between the compressed and the tensed layers. The results highlight the range of effects associated with the potential nonlinear response of the active structure under high levels of mechanical load.

Development of piezoelectric paint thick-film vibration sensors

2005 ◽  
Vol 219 (1) ◽  
pp. 1-9 ◽  
Author(s):  
J M Hale ◽  
J R White ◽  
R Stephenson ◽  
F Liu
Keyword(s):  
Thick Film ◽  
Dynamic Range ◽  
Strain Sensors ◽  
Fabrication Process ◽  
Vibration Monitoring ◽  
Structural Vibration ◽  
Dynamic Strain ◽  
Vibration Sensors ◽  
Piezoelectric Polymer ◽  
Adverse Environments

This paper describes a programme of trials of thick-film dynamic strain sensors made using ‘piezoelectric paint’. The fabrication process is described and it is shown that the sensitivity is comparable with that of other thick-film sensors and the piezoelectric polymer polyvnylidenefluoride (PVDF). A series of dynamic and environmental tests is described. The dynamic range and bandwidth are shown to be suitable for structural vibration monitoring, and to be largely unaffected by adverse environments (rain, frost, sunlight, etc.).

Electromechanical Impedance Modeling for Structural Health Monitoring

2012 ◽  
Author(s):  
Liuxian Zhao ◽  
Lingyu Yu ◽  
Mattieu Gresil ◽  
Michael Sutton ◽  
Siming Guo
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Electrical Impedance ◽  
Piezoelectric Materials ◽  
Fiber Composite ◽  
Mechanical Impedance ◽  
Experimental Result ◽  
Electromechanical Impedance ◽  
Structural Health ◽  
Aluminum Beam

Electromechanical impedance (EMI) method is an effective and powerful technique in structural health monitoring (SHM) which couples the mechanical impedance of host structure with the electrical impedance measured at the piezoelectric wafer active sensor (PWAS) transducer terminals. Due to the electromechanical coupling in piezoelectric materials, changes in structural mechanical impedance are reflected in the electrical impedance measured at the PWAS. Therefore, the structural mechanical resonances are reflected in a virtually identical spectrum of peaks and valleys in the real part of the measured EMI. Multi-physics based finite element method (MP-FEM) has been widely used for the analysis of piezoelectric materials and structures. It uses finite elements taking both electrical and mechanical DOF’s into consideration, which allows good differentiation of complicated structural geometries and damaged areas. In this paper, MP-FEM was then used to simulate PWAS EMI for the goal of SHM. EMI of free PWAS was first simulated and compared with experimental result. Then the constrained PWAS was studied. EMI of both metallic and glass fiber composite materials were simulated. The first case is the constrained PWAS on aluminum beam with various dimensions. The second case studies the sensitivity range of the EMI approach for damage detection on aluminum beam using a set of specimens with cracks at different locations. In the third case, structural damping effects were also studied in this paper.. Our results have also shown that the imaginary part of the impedance and admittance can be used for sensor self-diagnosis.

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