Quantifying Hole-Edge Crack of Bolt Joints by Using an Embedding Triangle Eddy Current Sensing Film

Hole-edge crack quantification of bolt joints is critical for monitoring and estimating structural integrity of aircraft. The paper proposes a new triangle eddy current sensor array for the purpose of increasing the level of quantifying hole-edge crack parameters, especially, the crack angle. The new senor array consists of triangular coils instead of planar rectangular coils. The configuration of the novel sensor array, including the excitation current directions and the excitation winding shape, is optimized by simulation. The ability of the proposed sensing film to identify the crack parameters has been verified by finite element simulations and experiments. Results shows that triangular coils with same current directions in circumferentially adjacent coils and opposite current directions in axially adjacent coils achieve better performance in sensor linearity and resolution compared to rectangular coils. In addition, it has also been proved that the sensing film has a good potential to identify the crack depth and length.

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A new interleaving eddy current array-based sensing film for fatigue crack quantification of bolted joints

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x21990891 ◽

2021 ◽

pp. 1045389X2199089

Author(s):

Hu Sun ◽

Junyan Yi ◽

Tao Wang ◽

Yishou Wang ◽

Xinlin Qing

Keyword(s):

Fatigue Crack ◽

Eddy Current ◽

Edge Crack ◽

Crack Detection ◽

Structural Integrity ◽

Bolted Joints ◽

Induced Voltage ◽

Coil Array ◽

Hole Edge ◽

Crack Angle

Fatigue crack quantification for bolted joints attracts much attention to determine the structural integrity for aircraft structures. In this paper, a new sensing film with interleaving eddy current array is proposed to evaluate the parameters of the hole-edge crack for single- or multiple-lap bolted joints. In this sensing film, the exciting layer is one coil throughout the hole wall which consists of a one-dimension rectangle coil array in the axial direction connecting in series, while the sensing layer is made up of two interleaving layers with a two-dimensional sensing coil array distributed in the circumferential and axial directions for each layer. Finite element simulation is conducted to study the effect of different crack parameters on the induced voltage of sensing coils. Simulation results reveal that the sensing film has no blind angle of crack detection but a strong capability of quantifying the crack angle, and the arctangent value of the ratio between interleaving coils can be used for estimating the crack angle. After the crack angle is estimated, induced voltages of sensing coils at this angle may be used to track the crack propagation in the axial or radial directions of the bolt hole. Experiments are conducted to verify the feasibility and effectiveness of the new sensing film to monitor the angle, depth, and length of the hole-edge crack of bolted joints.

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A novel eddy current array sensing film for quantitatively monitoring hole-edge crack growth in bolted joints

Smart Materials and Structures ◽

10.1088/1361-665x/aae54e ◽

2018 ◽

Vol 28 (1) ◽

pp. 015018 ◽

Cited By ~ 14

Author(s):

Hu Sun ◽

Tao Wang ◽

Qijian Liu ◽

Xinlin Qing

Keyword(s):

Crack Growth ◽

Eddy Current ◽

Edge Crack ◽

Bolted Joints ◽

Hole Edge ◽

Array Sensing

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On-site monitoring of bearing failure in composite bolted joints using built-in eddy current sensing film

Journal of Composite Materials ◽

10.1177/0021998320979737 ◽

2020 ◽

pp. 002199832097973

Author(s):

Qijian Liu ◽

Hu Sun ◽

Yuan Chai ◽

Jianjian Zhu ◽

Tao Wang ◽

...

Keyword(s):

Numerical Simulations ◽

Eddy Current ◽

Failure Modes ◽

Bolted Joints ◽

Bearing Failure ◽

Monitoring Method ◽

Current Sensing ◽

Site Monitoring ◽

Array Sensing ◽

Bearing Damage

Bearing damage is one of the common failure modes in composite bolted joints. This paper describes the development of an on-site monitoring method based on eddy current (EC) sensing film to monitor the bearing damage in carbon fiber reinforced plastic (CFRP) single-lap bolted joints under tensile testing. Configuration design and operating principles of EC array sensing film are demonstrated. A series of numerical simulations are conducted to analyze the variation of EC when the bearing failure occurs around the bolt hole. The results of damage detection in the horizontal direction and through the thickness direction in the bolt hole with different exciting current directions are presented by the finite element method (FEM). Experiments are performed to prove the feasibility of the proposed EC array sensing film when the bearing failure occurs in CFRP single-lap bolted joints. The results of numerical simulations and experiments indicate that bearing failure can be detected according to the variation of EC in the test specimen.

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Uniform eddy current probe based on GMR sensor array and image processing for NDT

2012 IEEE International Instrumentation and Measurement Technology Conference Proceedings ◽

10.1109/i2mtc.2012.6229366 ◽

2012 ◽

Cited By ~ 2

Author(s):

Octavian Postolache ◽

A. Lopes Ribeiro ◽

Helena Geirinhas Ramos

Keyword(s):

Image Processing ◽

Eddy Current ◽

Sensor Array ◽

Gmr Sensor

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Investigation of Rotating Eddy Current Testing Simulation Using Simplified Model

Journal of Multiscale Modelling ◽

10.1142/s1756973721420026 ◽

2021 ◽

Author(s):

Chenkai Yang ◽

Jiuhao Ge ◽

Baowang Hu

Keyword(s):

Simulation Model ◽

Eddy Current ◽

Crack Depth ◽

Eddy Current Testing ◽

Simplified Model ◽

Current Testing ◽

Application Condition ◽

Exciting Frequency ◽

Text Signal ◽

Peak Value

To reduce the time of simulation for rotating Eddy current testing (RECT) technique, a simplified model without modeling probe was proposed previously. However, the applicability of the simplified simulation model was unknown. In this paper, the applicability of the simplified model for the RECT technique was investigated. The application condition of the simplified model was provided by comparing it with the results of the traditional simulation model. The simplified model was suitable for the study of cracks shorter than 70% size of the uniform Eddy current induced by the probe in a traditional model or experiment. The experiment was conducted to validate the simplified model. Moreover, using the simplified model, the effects of crack depth, orientation, and exciting frequency were studied. The deeper the crack depth was, the greater peak value of [Formula: see text] signal was. The crack angle was linear with the phase of signal. The exciting frequency affected the amplitude and phase of the signal at the same time.

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