The purpose of this study is to establish a computational procedure to support the optimization of an EMAT configuration. In this study, computer simulations were performed to obtain the propagation behavior of ultrasonic waves generated by an EMAT and the signals received with an EMAT. The simulation results were compared with the corresponding experimental results to validate the simulation method. The simulation results reasonably matched the corresponding experimental results....
英字タイトル:
FEM simulation with consideration of electromagnetic interaction for transmitting and receiving ultrasonic waves with an EMAT

Abstract Ultrasonic guided waves have been widely applied to the long-range inspection of straight piping. Guided waves have many wave modes with different sound velocity. So, ultrasonic testing beyond welds and elbows is very difficult to interpret testing data. This paper reports the simulation and visualization of guided wave propagation via a large-scale 3D FEM code, which has over one billion elements and parallel computing system. The prediction of torsional guided wave propagation and reflected ...
英字タイトル:
Numerical simulation of torsional-mode guided wave inspection beyond elbows

We are developing remote filed eddy current testing (RFECT) method using pancake coils for evaluating local wall thinn ing of large diameter pipes. This paper shows a study to improve the detectability and sizing capability of this RFECT method. The study was performed by numerical calculations and laboratory experiments. The results show that introduci ng differential pick-up coils makes detection signals more stable and improves the detectability of our RFECT method....
英字タイトル:
Improvement of remote field eddy current testing using pancake coils

This paper shows phase characteristics of crack indications obtained with a multi-coil ECT probe, and proposes a method to reduce noise and extract crack indications from the detection signals of this multi-coil ECT p robe based on these phase characteristics. Because this multi-coil ECT probe performs two kinds of scanning patterns: U-scan and T-scan, and obtains two sets of signal distributions for one scanning area simultaneousl y, the proposed method uses a two-stage process that includes so-called a m...
英字タイトル:
Extraction of crack indications from ECT signals by using signal phase characteristics

A machine learning model is required to be interpretable for making its decision accepted by people. SHAP (Shapley Additive exPlanations) is a tool to show how much each of the features used for training a machine learning model contributes its decision. This paper shows an application of SHAP on a deep learning model for defect detection by normal beam UT as an example of nondestructive inspection problems....
英字タイトル:
Study on an interpretation technique for machine learning results with an example of defect detection by normal beam UT

Nuclear spent fuel intermediate storage facility is planned to be located in the Sea of Japan coast area. Therefore, there is risk of structure corrosion by sea salt aerosol. This study is the co rrosion risk evaluation and it's countermeasure of that facility....
英字タイトル:
Evaluation of Salt Damage Structure Located in the Coastal

Electromagnetic acoustic transducer (EMAT) is suited to monitoring because of its non-contacting nature. However, a standard EMAT tends to give overestimating results because the estimated thickness is associated with the average of varying thickness over an area under the coil of EMAT. To solve this problem, Point-Focusing EMAT (PF EMAT), which concentrates ultrasonic waves at a certain point, was applied to thickness gauging. This study evaluates the focusing property of PF EMAT and its applicability to l...
英字タイトル:
Evaluation of Point Focusing EMAT using ultrasonic wave visualization system and finite element analysis

Ultrasonic testing (UT) is one of the most appropriate non-destructive testing because of capabilities for flaw detection and flaw height sizing of flaw. Interpretation and analysis of UT data are not easy, to identify and classify relevant indications are sometimes very difficult. UT personnel shall be qualified to an appropriate level in accordance with a code and standard. In addition, personnel should keep and improve their skills. In this paper, an FEM UT simulation was applied to make UT training data...
英字タイトル:
Prototype of UT Training Simulator using Large Scale FEM Simulation