Temperature-compensated rosette eddy current array sensor (TC-RECA) using a novel temperature compensation method for quantitative monitoring crack in aluminum alloys

This paper investigates effects of temperature variation on output signal of rosette eddy current array (RECA) sensor and proposes a new RECA sensor with temperature compensation capability for quantitative monitoring crack of bolt-jointed structures. A temperature simulation experiment shows that temperature variation has a great influence on output signal AR of RECA sensor as crack does and even results in false alarm when environment temperature changes. Temperature-compensated RECA (TC-RECA) sensor using the new output signal ΔC considering impacts of conductivity and lift-off is developed to eliminate impacts of temperature variation on monitoring process. Then, the relation between crack length and output signal ΔC is obtained by an online monitoring experiment, which shows TC-RECA sensor can quantitatively monitor crack with an accuracy of 1 mm. Then, a temperature simulation experiment is performed to verify the sensor's ability to eliminate effects of temperature variation on monitoring process. Results shows that output signal ΔC just changes within about 0.5% when temperature changes from −20 °C to 70 °C, which has no effects on monitoring process. Finally, a crack monitoring experimental of a bolt-jointed structure under temperature disturbance is performed to verify the sensor's abilities of quantitative monitoring crack of bolt-jointed structures and temperature compensation. It can be concluded that TC-RECA sensor has the ability to eliminate effects of temperature variation and can quantitatively monitor crack of bolt-jointed structures with an accuracy of 1 mm.