A novel flexible eddy-current probe with high sensitivity for NDT

A high precision eddy current sensor for tip clearance measurement was proposed to assess the dynamic tip clearance measurement for aero-engine rotator. Based on the Lenz’s law, the eddy current sensor has high sensitivity, quick response speed and strong anti-interference capability, in addition, the simple geometry and easy installation are its main merits. The aim is to study the influence of planar coil structure parameters and excitation signal parameters on the sensor coil measurement, provide the basis for design of practical sensor in turbine tip clearance measurement. The dynamic calibration experiment verified the designed planar sensor coil, the results indicated the sensor resolution was 10μm and the measurement range was not less than 3mm. The dynamic experiment proved the measuring range, resolution, response speed of designed sensor can meet the requirement of turbine blade tip clearance measurement. The work provides experience in eddy current sensor design in different application, not only in turbine. And the future work will focus on the high temperature issues.

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A Solution to Ambiguities in Position Estimation for Solenoid Actuators by Exploiting Eddy Current Variations

Sensors ◽

10.3390/s20123441 ◽

2020 ◽

Vol 20 (12) ◽

pp. 3441 ◽

Cited By ~ 1

Author(s):

Niklas König ◽

Matthias Nienhaus

Keyword(s):

Eddy Current ◽

Signal To Noise Ratio ◽

Low Cost ◽

High Sensitivity ◽

Position Estimation ◽

High Signal ◽

Wide Field ◽

Fusion Algorithm ◽

Case Scenario ◽

Position Detection

Position estimation techniques for solenoid actuators are successfully used in a wide field of applications requiring monitoring functionality without the need for additional sensors. Most techniques, which also include standstill condition, are based on the identification of the differential inductance, a parameter that exhibits high sensitivity towards position variations. The differential inductance of some actuators shows a non-monotonic dependency over the position. This leads to ambiguities in position estimation. Nevertheless, a unique position estimation in standstill condition without prior knowledge of the actuator state is highly desired. In this work, the eddy current losses inside the actuator are identified in terms of a parallel resistor and are exploited in order to solve the ambiguities in position estimation. Compared to other state-of-the-art techniques, the differential inductance and the parallel resistance are estimated online by approaches requiring low implementation and computation effort. Furthermore, a data fusion algorithm for position estimation based on a neural network is proposed. Experimental results involving a use case scenario of an end-position detection for a switching solenoid actuator prove the uniqueness, the precision and the high signal-to-noise ratio of the obtained position estimate. The proposed approach therefore allows the unique estimation of the actuator position including standstill condition suitable for low-cost applications demanding low implementation effort.

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High Sensitivity Eddy Current Probe for Inspection of Low Conductivity Materials

10.1063/1.1711648 ◽

2004 ◽

Author(s):

R. Sikora

Keyword(s):

Eddy Current ◽

High Sensitivity

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Giant Magnetoresistance Imaging for NDE of Conductive Materials

MRS Proceedings ◽

10.1557/proc-591-151 ◽

1999 ◽

Vol 591 ◽

Cited By ~ 1

Author(s):

E. S. Boltz ◽

S. G. Albanna ◽

A. R. Stallings ◽

Y. H. Spooner ◽

J. P. Abeyta

Keyword(s):

Eddy Current ◽

Giant Magnetoresistance ◽

High Spatial Resolution ◽

Low Frequency ◽

High Sensitivity ◽

Low Noise ◽

Conductive Materials ◽

Gmr Sensors ◽

Current Sensors ◽

Gmr Sensor

ABSTRACTTraditional coil-based eddy-current sensors are severely limited in their ability to detect small buried defects, defects under fasteners and deeply buried cracks and corrosion. TPL has developed eddy-current sensors and arrays based on the use of Giant Magnetoresistance (GMR) sensor elements. GMR offers high sensitivity, very wide bandwidth and low noise from DC to over 1 GHz. Coupled with the ability to fabricate GMR sensors with micron-level dimensions, these new eddy-current sensors offer an ideal technology for inspections requiring high spatial resolution and low-frequency, deeply-penetrating fields.

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Eddy Current Transducer Dedicated for Sigma Phase Evaluation in Duplex Stainless Steel

Journal of Sensors ◽

10.1155/2012/851231 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6

Author(s):

Grzegorz Psuj ◽

Tomasz Chady ◽

Cesar Giron Camerini

Keyword(s):

Stainless Steel ◽

Electrical Properties ◽

Duplex Stainless Steel ◽

Eddy Current ◽

Sigma Phase ◽

High Sensitivity ◽

Current Transducer ◽

Differential Type ◽

Phase Evaluation ◽

Eddy Current Transducer

The paper describes a new transducer dedicated for evaluation of a duplex stainless steel (DSS). Different phases which exist in DSS have influence on mechanical as well as on electrical properties. Therefore, an eddy current transducer was utilized. In order to achieve high sensitivity, a differential type of the transducer was selected. The performance of the transducer was verified by utilizing the samples which had a different amount of sigma phase.

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