International Journal of Applied Electromagnetics and Mechanics - Volume 52, issue 1-2

Authors: Cong, Ming | Wu, Xinjun

Article Type: Research Article

Abstract: A new magnetostrictive steady-state guided wave technique (MST) based on long time excitation is proposed for Nondestructive Evaluation (NDE) and Structural Health Monitoring (SHM) in pipes. Due to the non-contact inspection, it has no need to consider the influence on vibration state while moving sensors along the pipe. Both simulation and experimental results show that the vibration state is associated with specific propagating guided wave mode and the defect causes an obvious change of the steady-state stage vibration amplitude at certain specific positions along the pipe, which can be utilized for defect location. Moreover, the precision of defect location increases …with the excitation frequency increasing. Show more

Keywords: Long time excitation, non-contact inspection, steady-state vibration, defect detection

DOI: 10.3233/JAE-162227

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 331-337, 2016

Authors: Zhang, Qing | Wu, Xinjun | Li, Jian

Article Type: Research Article

Abstract: Models of the uniform wall thinning, a cylindrical through-hole for non-magnetic plate and the ferrite cored probes have been solved using the truncated region eigenfunction expansion (TREE) method. However, the solution of Pulsed Eddy Current Testing (PECT) for steel plate with a flat-bottom hole has seldom been given. By constructing the expressions of magnetic vector potential and solving the eigenfunction in the region where the flat-bottom hole placed, the analytical solution of PECT for the ferromagnetic plate with a flat-bottom hole is obtained. The solution is verified by a 2-D Finite Element Modeling (FEM), and the theoretical results …obtained with the TREE method are in good agreement with the numerical ones obtained with a 2-D FEM package. The study proposes a theoretical method to analyze the PECT for wall thinning with the size similar to the probe. Show more

Keywords: Pulsed eddy current testing, ferromagnetic materials, flat-bottom hole, analytical method

DOI: 10.3233/JAE-162112

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 339-345, 2016

Authors: Li, Yong | Yan, Bei | Li, Da | Li, Yili | Chen, Zhenmao

Article Type: Research Article

Abstract: Subsurface Corrosion (SSC) has posed a severe threat to the integrity of in-service conductive structures. Although Pulsed Eddy Current technique (PEC) has been proven applicable regarding non-destructive inspection of SSC, it has been found disadvantageous in terms of Signal-to-noise Ratio (SNR) and sensitivity to SSC, etc. In light of this, this paper proposes Pulse-modulation-based Eddy Current technique (PMEC). The advantages of PMEC over PEC have been analyzed via simulations based on analytical modeling and a series of experiments. Through theoretical and experimental investigations, it has been found that PMEC realizes the elaborate inspection of conductive structure, and has higher sensitivity …in detection and evaluation of SSC than PEC. Show more

Keywords: Electromagnetic non-destructive evaluation, pulse-modulation-based eddy current, subsurface corrosion, analytical modeling

DOI: 10.3233/JAE-162158

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 347-356, 2016

Authors: Feng, Bo | Kang, Yihua | Sun, Yanhua | Yang, Yun | Yan, Xizi

Article Type: Research Article

Abstract: In order to get a thorough comprehension on how the eddy current affects the MFL signal in high speed testing, distribution of eddy current and the magnetic field generated by it are first analysed theoretically. Then, the magnetization statuses of the pipe in static and motional situations are investigated by finite element simulation. Finally the external and internal defect signals are extracted in both static and motional cases. The results show that, in high speed testing, the magnetic field is strengthened at the outer surface and weakened at the inner surface, which increases the external defect signal but decreases internal …defect signal. Show more

Keywords: Magnetic flux leakage (MFL), high speed testing, eddy current effect, velocity effect

DOI: 10.3233/JAE-162076

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 357-362, 2016

Authors: Ramos, Helena G. | Baskaran, Prashanth | Ribeiro, Artur L.

Article Type: Research Article

Abstract: The objective of this paper is a proof of concept on the possibility to measure the same magnetic fields, by the principle of dilation invariance. According to this principle, dilation of the dimensional and electrical parameters of a probe and a plate with crack reproduces the same magnetic field (measured at every dilated point) which was produced by a probe and a plate with crack, without dilation. This implies that, in order to evaluate the performance of eddy current method in a specific industrial case study, one can carry out tests in a scaled model in the laboratory and then, …extend the conclusions to the real situation by using dilation invariance principle. The experimental and simulation results show a good agreement of crack detection by using two eddy current probes of which one is the dilated version of the other. Show more

Keywords: ECT, eddy current testing, nondestructive evaluation, dilation invariance principle

DOI: 10.3233/JAE-162067

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 363-369, 2016

Authors: Iida, Mirai | Marinova, Iliana | Saito, Yoshifuru

Article Type: Research Article

Abstract: Ferromagnetic materials are widely used for various artificial products such as cars, trains, ships and so on. Because of its mechanical property, iron steel is most popular in use for the frame materials. Nondestructive testing of iron steel is an extremely important way to maintain their mechanical reliability. It is well known fact that the Barkhausen signals are emitted from only the ferromagnetic materials having magnetic domain structures. Also this signal varies depending upon their past mechanical as well as radioactive stress histories. In the present paper, we have applied a generalized frequency fluctuation analysis to the Barkhausen signals …to detect the various mechanical stresses. Surprisingly, it has been succeeded in clarifying that application of our frequency fluctuation analysis to the Barkhausen signals makes it possible to detect the several kinds of mechanical stress. Show more

Keywords: Barkhausen signal, frequency fluctuation, signal processing, least squares

DOI: 10.3233/JAE-162132

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 371-379, 2016

Authors: Liu, Haochen | Xie, Shejuan | Pei, Cuixiang | Chen, Zhenmao

Article Type: Research Article

Abstract: In this paper, a new efficient numerical method based on the finite element method (FEM) and the frequency domain summation (FDS) strategy is proposed for the simulation of the pulsed infrared thermography non-destructive testing. With use of the FDS strategy, the temperature distribution due to a pulsed thermal source is simulated based on the thermal response of series of single-frequency sinusoidal heat sources. An interpolation strategy is also adopted to reduce the necessary number of harmonic frequency responses to be calculated, and consequently the simulation time is saved. A comparison of the FDS strategy and the direct time domain integration …method is also presented, which indicates that the FDS strategy can simulate pulsed thermography problem with high precision and can promote simulation efficiency. Show more

Keywords: Numerical simulation, pulse thermography, frequency domain method, NDT

DOI: 10.3233/JAE-162121

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 381-389, 2016

Authors: Xu, Jiang | Sun, Yong | Cong, Ming | Wu, Xinjun

Article Type: Research Article

Abstract: The short cable is adopted widely in arch bridges and suspension bridges. The tension is an important parameter to guarantee the safety of the bridges in the practical application. Due to the bending stiffness and boundary condition effects, the tension of short cable is difficult to achieve accurate measurement using the flexural vibration method. A feasibility of tension measurement method for the short cable using steady state longitudinal mode guided waves based on the magnetostrictive effect is investigated. The major difference between this method and the magnetostrictive guided wave testing method is that the steady state response of the cable …is employed to measure the tension. The cable is established the steady state longitudinal vibration with long time excitation based on the magnetostrictive effect. The longitudinal vibration is induced based on the inverse magnetostrictive effect. The natural frequencies of the cable are extracted from receiving data and employed to estimate the tension. The feasibility experiment results show that the natural frequencies rapidly increase with increasing the tension in low level and slightly increase with increasing the tension in high level, especially in higher modes. The results indicate that the proposed method is able to measure the tension of the short cylinder structure, but the relationship between the tension and the natural frequencies is non-linear. Show more

Keywords: Tension measurement, longitudinal mode guided wave, short cable, magnetostrictive effect

DOI: 10.3233/JAE-162110

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 391-397, 2016

Authors: Tu, Jun | Qiu, Gongzhe | Chen, Hao | Song, Xiaochun

Article Type: Research Article

Abstract: In order to make the industrial testing and maintenance tasks for the tank floor safer, an automatic navigation magnetic flux leakage testing robot is designed. A fast multi circle detection method is presented for the testing robot with laser ranging location and differential driven technology. The calculation for the orientation deviation angle and the position of the robot is derived. The experimental results demonstrate that the proposed detection method and the incremental PID control algorithm perform the perfect tracking effect with high efficiency.

Keywords: Multi circle detection method, automatic navigation, magnetic flux leakage testing, tank floor

DOI: 10.3233/JAE-162087

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 399-405, 2016

Authors: Chen, Yijin | Xie, Shilin | Zhang, Xinong

Article Type: Research Article

Abstract: A new structure damage identification method is proposed based on wavelet packet analysis of the time domain response. It is known that the distribution of the wavelet packet node energy of response varies if the structure is damaged. The presented identification approach considers the variation rate of variance (VRV) of each node energy distribution as the damage detection index. Through decompositions of the time domain responses of intact and damaged structures using the wavelet packet transformation, the location and the degree of damage in the structure can be identified. Both the simulated and experimental studies on damage identifications are carried …out for beam structure with crack based on the proposed method. The identification results show that the presented method is able to identify damages more accurately in the case of noise contamination compared with the previous methods. Show more

Keywords: Damage identification, wavelet, wavelet packet, variation rate of variance, impact load

DOI: 10.3233/JAE-162134

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 407-414, 2016