Applications of Flexible Ultrasonic Transducer Array for Defect Detection at 150 °C

Jeanne-Louise Shih,Cheng-Kuei Jen,Chun-Hsiung Chiu,Kuo-Ting Wu,Jiunn-Woei Liaw,Jing-Chi Tzeng

doi:10.3390/s130100975

Jeanne-Louise Shih, Cheng-Kuei Jen + Show 4 more

Open Access

https://doi.org/10.3390/s130100975

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Abstract

In this study, the feasibility of using a one dimensional 16-element flexible ultrasonic transducer (FUT) array for nondestructive testing at 150 °C is demonstrated. The FUT arrays were made by a sol-gel sprayed piezoelectric film technology; a PZT composite film was sprayed on a titanium foil of 75 μm thickness. Since the FUT array is flexible, it was attached to a steel pipe with an outer diameter of 89 mm and a wall thickness of 6.5 mm at 150 °C. Using the ultrasonic pulse-echo mode, pipe thickness measurements could be performed. Moreover, using the ultrasonic pulse-echo and pitch-catch modes of each element of FUT array, the defect detection was performed on an Al alloy block of 30 mm thickness with a side-drilled hole (SDH) of ϕ3 mm at 150 °C. In addition, a post-processing algorithm based on the total focusing method was used to process the full matrix of these A-scan signals of each single transmitter and multi-receivers, and then the phase-array image was obtained to indicate this defect- SDH. Both results show the capability of FUT array being operated at 150 °C for the corrosion and defect detections.

Highlights

Multiple ultrasonic transducer (UT) arrays [1,2,3,4], e.g., phase-array UT, are becoming attractive for the applications of nondestructive testing (NDT) and structural health monitoring (SHM) due to the efficient inspection, compared to a single element UT
Under high temperature conditions are needed for industry, especially for petrochemical and nuclear power plants, the flexible ultrasonic transducer (FUT) arrays may show their applicability for the corrosion and defect detections
The applications of 1D FUT arrays, PZT composite (PZT-c) film sprayed on Ti foils of 75 μm and 35 μm, to ultrasonic thickness measurement and defect detection for specimens at 150 °C were presented

Summary

Introduction

Multiple ultrasonic transducer (UT) arrays [1,2,3,4], e.g., phase-array UT, are becoming attractive for the applications of nondestructive testing (NDT) and structural health monitoring (SHM) due to the efficient inspection, compared to a single element UT. The main purposes of ultrasonic measurement are for the defects and corrosions detections in materials These ultrasonic measurements are often required to operate under high temperatures condition [1,2,4] for the in-service inspections of electrical power plants and petrochemical plants etc. To develop flexible UT arrays [5] applicable at high temperature [4] and on curved surface is extremely of importance to the industrial in-service inspection. Since the in-service NDT and SHM under high temperature conditions are needed for industry, especially for petrochemical and nuclear power plants, the FUT arrays may show their applicability for the corrosion and defect detections

Fabrication of Piezoelectric 1D FUT Array

Theory

Experimeental Resullts and Disccussion

Conclusions