高温激光-仅线圈式表面波EMAT优化设计及应用OA

Aimed at the problems of traditional permanent magnet or liquid-cooled permanent magnet type Electro-Magnetic Acoustic transducer(EMAT),such as large volume,easy demagnetization of permanent magnet at high temperature and difficulty in sustained high temperature detection,a laser coil-only Rayleigh Wave(RW)EMAT detec-tion method for high-temperature-sustained on-line monitoring is proposed.A finite element model for field-circuit cou-pling analysis of the aluminum alloy laser coil-only RW EMAT detection process based on the surface constraint mechanism was established,and the effects of key design parameters such as the excitation coil of the coil-only RW EMAT on the amplitude and wave packet width of the RW detection were analyzed by using orthogonal experimental method,according to which,the optimal design parameter combinations of the coil-only RW EMAT was obtained and verified by experiments.The laser coil-only RW EMAT high-temperature on-line detection system was developed,and the on-line detection experiment of surface crack defects of high-temperature aluminum alloy at 20-500℃was carried out.The results show that the number of wire splitting and coil turns of the receiving coil(meander coil)have a major influence on the received signal amplitude and wave packet width of the coil-only RW EMAT,respectively.The receiv-ing amplitude of the optimized coil-only RW EMAT is increased by 1.67 times.Furthermore,the on-line detection of surface crack defects of 500℃high-temperature aluminum alloy can be realized by using the differential circuit device and matching the width of the laser line light source with the turn spacing of the coil-only RW EMAT coil.The proposed method provides theoretical support and technical guidance for laser coil-only RW EMAT high-temperature on-line non-destructive testing and monitoring.