マイクロ波を用いたステンレス合金の非接触ひずみ計測

抄録

Stainless alloy is widely used in implants, dams and bridges because of its high corrosion resistance. However, these structures can be exposed to loads during their useful life and cause plastic deformation. Therefore, it is essential to know the plastic strain of the material in order to control the quality of the product. The conventional way to measure strain is the strain gauge method, but since physical contact is required at the time of gage attachment, a method to measure strain in non-contact fashion is required. Therefore, in this research, we focused on microwaves often used in nondestructive testing. Microwaves have less influence on the human body compared to X-ray. Unlike ultrasonic waves, microwaves do not require a transmission medium and can propagate in air favorably and at high speed. Therefore, we used microwaves to measure the electrical resistivity of plastically deformed test pieces. As a result, correlations were confirmed between the measured electrical resistivity and strain, and it was shown that the strain of stainless steel could be evaluated from the measured electrical resistivity.