Angular Spectral Density and Information Entropy for Eddy Current Distribution

Chen, Guolong; Zhang, Weimin

doi:10.3390/e18110392

Cited by 9 publications

(7 citation statements)

References 13 publications

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“…In the finite element models, the geometric dimension was adjusted as paper [ 23 ]. Every model included three parts: a specimen domain, an air domain and an exciting coil.…”

Section: Methodsmentioning

confidence: 99%

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Two Novel Information Entropy Indices for Analysis of the Eddy Current Distribution

Chen

2018

Entropy

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The Koch curve exciting coil eddy current sensor is a kind of novel flexible planar eddy current probe. In this study, an intersection angle spectrum entropy index and a radial direction energy spectrum entropy were proposed to evaluate the eddy current distribution. Eddy current distributions induced by one turn of a circular coil and one turn of a second order Koch curve coil feed with different exciting frequency alternative currents and at different lift-off distances, were simulated and the eddy current distributions varying with lift-off distance in different exciting frequencies were compared by the two proposed indices. With the increase of the lift-off distance or the decrease of exciting frequency, the similarity between the shape of the Koch curve and the eddy current distribution became weakened and the degree of the concentration of the eddy current distribution in the specimen under the exciting coil was loosened.

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“…In the finite element models, the geometric dimension was adjusted as paper [ 23 ]. Every model included three parts: a specimen domain, an air domain and an exciting coil.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, Chen et al [ 21 ] proposed using the fractal Koch curve as exciting coils of the eddy current sensor. To quantitatively study the eddy current distribution, Zhang et al [ 22 ] and Chen et al [ 23 ] proposed using the angular spectrum and information entropy.…”

Section: Introductionmentioning

confidence: 99%

Two Novel Information Entropy Indices for Analysis of the Eddy Current Distribution

Chen

2018

Entropy

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“…In terms of an event, x i , it has a probability, p i , i.e., p i = P(X = x i ); r is the base of the logarithm, which usually takes r = 2 [28][29][30][31][32][33] (In this study, we take r = 2). The entropy H(X) possesses a maximum property, which implies that the measure will be maximal if all the outcomes are equally likely.…”

Section: Evaluation Methods For Contact Strain-energy Distributionmentioning

confidence: 99%

Entropy-Based Method for Evaluating Contact Strain-Energy Distribution for Assembly Accuracy Prediction

Yan

Jin

Huang

et al. 2017

Entropy

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Abstract:Assembly accuracy significantly affects the performance of precision mechanical systems. In this study, an entropy-based evaluation method for contact strain-energy distribution is proposed to predict the assembly accuracy. Strain energy is utilized to characterize the effects of the combination of form errors and contact deformations on the formation of assembly errors. To obtain the strain energy, the contact state is analyzed by applying the finite element method (FEM) on 3D, solid models of real parts containing form errors. Entropy is employed for evaluating the uniformity of the contact strain-energy distribution. An evaluation model, in which the uniformity of the contact strain-energy distribution is evaluated in three levels based on entropy, is developed to predict the assembly accuracy, and a comprehensive index is proposed. The assembly experiments for five sets of two rotating parts are conducted. Moreover, the coaxiality between the surfaces of two parts with assembly accuracy requirements is selected as the verification index to verify the effectiveness of the evaluation method. The results are in good agreement with the verification index, indicating that the method presented in this study is reliable and effective in predicting the assembly accuracy.

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“…Thus, many indices were proposed to quantitatively evaluate the EC distribution, such as interaction efficiency, information entropy of angular spectrum, information entropy of intersection angle spectrum entropy, and a radial direction energy spectrum. [19][20][21] The information theory was first used to evaluate the EC distribution, but there are many different indices in the information theory. Thus, in this study, the relative entropy and the cross entropy are considered as quantitative indices to evaluate the EC distribution, because the relative entropy measures the ''distance'' between the two EC distribution, and the cross entropy can prove the correctness of the relative entropy and the information entropy.…”

Section: Introductionmentioning

confidence: 99%

Quantitative evaluation of eddy current distribution by relative entropy and cross entropy

Chen

Zheng

2021

Measurement and Control

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Koch curve exciting coil of an eddy current probe can adjust the eddy current distributing in more directions at a small domain to enhance the sensitivity of eddy current probe for short defect detection. In this study, a relative entropy and a cross entropy of tangential intersection angle spectrum are proposed to evaluate the eddy current distributions in the different directions when the eddy current probe is positioned at different lift-off distances and excited by different exciting frequency alternative currents. The eddy current distributions induced by a circular and a fractal Koch curve exciting coils are analyzed by the two entropy indices. With the increasing of the lift-off distance or the decreasing of the exciting frequency, the eddy current distributions induced by the Koch curve exciting coil are close to those induced by the circular exciting coil.

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Angular Spectral Density and Information Entropy for Eddy Current Distribution

Cited by 9 publications

References 13 publications

Two Novel Information Entropy Indices for Analysis of the Eddy Current Distribution

Two Novel Information Entropy Indices for Analysis of the Eddy Current Distribution

Entropy-Based Method for Evaluating Contact Strain-Energy Distribution for Assembly Accuracy Prediction

Quantitative evaluation of eddy current distribution by relative entropy and cross entropy

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