Hitoshi Yoshikawa

Verification of ultrasonic transducer characteristics determined in an inverse problem based on laser measurements

Publisher Summary Boundary integral equation approach is investigated for solving inverse problems related to ultrasonic nondestructive determination of defects in structures for some time. The setting of these elastodynamic inverse problems assumes that one knows both incident waves to illuminate the defects, and the scattered waves from the defects. However, neither of these waves are easily measured in experiments using ultrasonic transducers, mainly because the output of ultrasonic transducers has not been related to physical quantities in a quantitative manner. In view of this, this chapter considers an inverse problem that uses real data obtained with a laser interferometer to determine the waves from the transducer. This chapter deals with the description of the experiment carried out for the present analysis. The specimen used in this experiment has a circular cylindrical hole as an artificial defect. This specimen is designed so that one may obtain data to determine the elastic wave from the transducer, and measure the scattered wave from the defect at the same time. After a brief recapitulation of the inverse problem of determining the elastic wave from the transducer, there is a brief discussion on BIE analysis for estimating the scattered wave from the defect.