Point-Focusing Shear-Horizontal Guided Wave EMAT Optimization Method Using Orthogonal Test Theory

Abstract

As a class of devices used in sound detection, electromagnetic acoustic transducers (EMATs) have been widely used in the field of nondestructive testing (NDT) owing to their advantages such as contact-free operation, wide applicability, and high performance. However, their low energy-conversion efficiency is the main drawback that limits usage in industrial testing. In this work, we report the effect of different parameters of the point-focusing shear-horizontal EMAT (PFSH_EMAT) on the signal intensity of the receiving transducer. The impact factors of the focusing transducer are as follows: number of magnets in a row m, fan-shaped periodic permanent magnet (FPPM) remanence magnetization Br, coil width w, coil winding number n, aperture angle , focal length IF, life-off distance h1, excitation current frequency fc and current amplitude Ic. To improve the analysis efficiency, and L32(4 9) orthogonal table is used to investigate the nine different factors at four levels, which can be calculated through finite element simulations. The effect of each factor on the signal intensity is obtained by range analysis, and the influence degree of each factor is obtained, and the parameter combination is optimized by analyzing the test results to improve the PFSH-EMAT's performance. The experimental results show that the optimized PFSH-EMAT is 170% more efficient than the average of the top-three signal intensities in the orthogonal test, which proves the effectiveness of the proposed optimization method.

Pulse injection simulation based on the coupling of transient flow in tubing and fracture propagation in reservoirs

“…To analyze the combined action of multiple parameters in the scheme, an orthogonal design method is applied. This method, which is widely used in multi‐factor and multi‐level problems, has the advantages of high efficiency 29,30 . The evaluation indexes in this orthogonal design are the maximum wellhead pressure and breakdown pressure.…”

“…This method, which is widely used in multi-factor and multi-level problems, has the advantages of high efficiency. 29,30 The evaluation indexes in this orthogonal design are the maximum wellhead pressure and breakdown pressure. As shown in Table 4, there are five influence factors, including t 2 , Δt 3 , Δt 4 , Δt 5, and Δq.…”

Defect Detection and Identification of Point-Focusing Shear-Horizontal EMAT for Plate Inspection

“…In order to obtain the characteristics of the SH-guided wave when it encounters defects, all parameters of the transducer are fixed: excitation current amplitude I = 50 A, current frequency f = 1 MHz, aperture angle θ = 60•, focal length lF = 100 mm, coil turns number n = 7, lift-off distance d = 1 mm, and remanence magnetism of the PPM B = 1.2 T. To study the general rules of defect detection, these parameters are set to values within a feasible interval to ensure the recognizability of the received signal. To further obtain the optimal value, the orthogonal test method can be considered to obtain the optimal combination of parameters [26].…”

Numerical Study and Optimal Design of the Butterfly Coil EMAT for Signal Amplitude Enhancement

“…It is noteworthy that these representative points have uniform dispersion and neatly comparable characteristics. The orthogonal table is used as the main tool of orthogonal test theory, which is selected based on the number and level of factors in the test, and the representative points are selected from the comprehensive test, which can achieve results equivalent to those of a large number of full−scale tests using a minimum number of tests [23]. Therefore, orthogonal test theory is widely used.…”