The Research On An Inductively Coupled Wireless Ultrasonic Sensor

Ultrasonic nondestructive testing(NDT)is widely used in defect detection and structural measurement for its excellent performance.The ultrasonic sensor is the key device of ultrasonic nondestructive testing,which can realize the mutual conversion between the signal and the ultrasonic signal.However,with the expansion of the application field of NDT,we are more stringent on the standards of ultrasonic sensors.Conventional piezoelectric ultrasonic sensors will cost more time to install,and oxidation also affects the accuracy of the detection.The use of embedded sensors can effectively solve this problem.However,embedded sensors with wired direct connection affects the structure of the material.Therefore,a wireless driven piezoelectric ultrasonic transducer based on inductive coupling wireless energy transmission theory is studied in this paper.we first introduces the background and current situation of ultrasonic NDT and wireless power transmission,The main propagation characteristics of ultrasonic propagation in medium are introduced,Next,we discussed the theory of wireless energy transmission based on Faraday's law of electromagnetic induction,the magnetic field distribution of the coupled coil.Then the coupling coefficient and energy transmission efficiency of the coil are calculated.And the compensation technology in inductively coupled coils is introducedThen the concept model of the sensor is introduced,and then the equivalent circuit is established based on the concept model,and the physical structure of the wireless sensor is analyzed.Then using the Ansoft finite element simulation software Maxwell,parameters of the physical structure of the sensor are analyzed,discussed the coupling coil shape,coil gap distance,horizontal distance and coupling coil joining the ferrite magnetic material of the coil self inductance and mutual inductance coefficient influence the coupling performance analysis.Based on the sensor structure model,the hardware and software design of the circuit is completed,including the drive signal transducer and the ultrasonic signal Receiver.Finally,the output performance of wireless sensor is studied through experiments.Compared with simulation,we have discussed the driving effect of coupling coil on piezoelectric ceramics.Through experiments,we explored the performance of wireless sensor in the excitation of ultrasonic Lamb wave in aluminum alloy plate.The results verify the feasibility of wireless sensor to inspire proper ultrasonic signal.