Research And Design Of Detection System For High Strength Broadband Ultrasonic Transducer

At present, with the development of ultrasonic testing technology, the ultrasonic applications of many industries put forward higher requirements when the ultrasonic transducers are used to send and receive ultrasonic signals. Mainly in: Large emission intensity of the ultrasonic transducer, high sensitivity and carrying large amounts of information. All in all, there is a need to improve the working bandwidth and emission intensity of ultrasonic transducers. Now, Manufacturers mainly use expensive composite materials to achieve broadband effect at home and abroad. In order to enhance the transmission power, the researchers generally use the amplifier,And research in this area is relatively blank. Based on this, different from the existing research results, this paper proposes to design the high strength broadband ultrasonic transducer by multi frequency synthesis focusing. The main work is as follows:(1) Through the acoustic analysis of point sound source, the superposition principle analysis of mixing acoustic and analysis about acoustic field focusing of tapered pipe, The paper points out that the converging conical tube has good acoustic focusing function, which can effectively enhance the sound pressure of transmitter. At the same time, The possibility of wide band separation and re synthesis was analyzed, and the design ideas are demonstrated that narrow band can be combined into a wide band, which provides a theoretical basis for the design of "high strength" and "wide band" performance.(2) The structure principle diagram of high strength broadband ultrasonic transducer was designed,and the apered pipe was determined as the "high strength" method. Then, three ways of the broadband sound source module are presented, including the trapezoidal combination, the cylindrical combination and the sector combination. Finally,it is found that the best design scheme of broadband sound source is the cylindrical combination by comparing.(3) In order to design the 3D model and the simulation model of high strength broadband ultrasonic transducer through parameter settings, I have studied the PZFlex ultrasound simulation software in depth. And three factors are found to have influence on the sound field intensity of the transducer, including the material of the tapered pipe, the focal length and the length of the central axis. Meanwhile,it is verified that the broadband performance of the transducer could be achieved by superimposing the narrowband. And the superimposed adjacent narrow band should be chosen as sound source selection in order to achieve the optimal results.(4) A practical platform for high strength broadband ultrasonic transducers is established.And three frequency response estimation algorithms,which respectively based on the least square criterion, the minimum mean square error criterion and the regression model,are proposed for the detection system. Finally,it’s found that the algorithm is optimal which based on the least mean square error criterion,when comparing the three algorithms.(5) The high strength broadband ultrasonic transducer is composed of tapered pipe material and broadband sound source module.And the tapered pipe material is produced by the 3D printer of laboratory while the broadband sound source module is made up of different narrowband chip. Finally,narrowband sound source made of single chip and broadband sound sources made of cylindrical combined multi chip were measured and compared in the experimental platform,which proved that the design scheme of the paper can achieve broadband effect.Overall, "High strength" and "broadband" performance expectations can be achieved through rationally configuring the tapered pipe and broadband sound source. And the whole design result has certain application significance in the field of ultrasonic testing.