Study On Acoustic Field Characteristics Of Direct Conductor EMAT Phased Array Synthesis Radiation

Whole aluminum engine for its light quality,less fuel consumption,heat dissipation good,but due to poor material aluminum corrosion resistance and strength is very easy to cause the corrosion defect is generated in cylinder body and the engine as the core part of the whole vehicle,the stand or fall of its performance directly determines the overall car safety,so how to evaluate the engine internal defects and become a problem.Piezoelectric ultrasonic phased array for nondestructive testing technology is an effective approach to detection of internal defects in engine cylinder block,but restricted by coupling agent,the applicable range and EMAT without using coupling agent nondestructive detection of this technical advantage to supplement the piezoelectric ultrasonic phased array technology gap,but the downside is a single coil can change efficiency is very low.After the EMAT combined with ultrasonic phased array of EMAT phased array for nondestructive testing technology with the advantages of these two kinds of testing technology,more broad prospects for development.In this paper,in view of the EMAT phased array radiation sound field to study the theoretical part,the time-domain and frequency-domain models of EMAT phased array are established by combining the principle of energy transfer of EMAT with the principle of piezoelectric ultrasonic phased array acoustic beam control,and the theoretical part of radiation acoustic field is studied.The time domain model of EMAT phased array is established,and the whole process of excitation and propagation of EMAT phased array ultrasonic wave is simulated.Establishing the frequency domain model of EMAT phased array: Combining the energy transfer principle of EMAT with the deflection principle of ultrasonic phased array beam,a beam deflection model of EMAT phased array was established.The effects of beam deflection Angle,excitation current frequency,array element width and array element spacing on the radiated sound field were studied and analyzed.By combining EMAT energy conversion principle with ultrasonic phased array beam focusing principle,the EMAT phased array beam focusing model is established,and the effects of excitation current frequency,array element width,array element spacing and array element number on its radiated sound field are studied and analyzed.Combining the principle of EMAT energy transfer with the principle of focusing and deflecting of ultrasonic phased array beam,a focusing and deflecting model of EMAT phased array beam is established,and the effect of beam deflection Angle on its radiated sound field is studied and analyzed.Analysis of three different beam synthesis radiation sound field with the main parameters of EMAT phased array,determine the main parameters selection range of EMAT phased array,providing theoretical guidance for the design of transducer.