Research Of The Air-ultrasonic Transducer And Its Transmitting And Receiving Device

The air-ultrasonic testing can raise the test range of the specimen and increase the service life of the ultrasonic transducer, meanwhile, it also can detect the hyperthermia welded specimens in real time. So the relevant research is paid enough attention in the welding field.The air-ultrasonic equipment and the ultrasonic transducer are analyzed systematically, and the ultrasonic pulse transmitting and receiving device are researched and produced in the paper. Isolation Gate Bipolar Transistor (IGBT) is used as a switching element in the ultrasonic pulse transmitting device, which increases the controlling precision of the width of the transmitting pulse, the flat-staggered amplifier is used to magnify the ultrasonic signal undistortionally. Meanwhile, the main circuit of the air-ultrasonic pulse transmitting device is analyzed and the equivalent circuit of the main circuit is established. Then the equivalent circuit is calculated quantitatively and actually analyzed, the complex operational regularity of the circuit and the affection of the physical parameters (such as dynamic capacity, dynamic induction) on the circuit waveform are discovered, the main element parameters (such as resonance induction L₀, static capacity Co, charging capacity C₂) of the main circuit are optimized, the main recommended parameters of the main circuit of the ultrasonic pulse transmitting device are obtained, thus the electrical match of the air-ultrasonic pulse transmitting device is well realized.The structural design of the ultrasonic transducer is an important factor on realizing the air-ultrasonic test, for accomplishing the match of the acoustic impedance and increasing the transmissivity of the ultrasonic, the reorganization of the ultrasonic transducer is also designed, and the performance of the revamped air-ultrasonic transducer is tested in the paper. It is stated that the forward amplitude voltage of the ultrasonic pulse waveform of the revamped ultrasonic has a further improvement. The spectrum analysis of the air-ultrasonic waveform (with matcher) indicates that when the matcher thickness is calculated at the highest spectrum and the subsequent higher spectrum of the pulse waveform, it can obtain a better result. But all the highest spectrum of the air-ultrasonic waveform moves to the high frequency zone in the experiment, which is a possible important reason that the testing extent of the air-ultrasonic transducer is limited.Such research result has an important engineering applied and theoretical value on achieving the air-ultrasonic nondestructive examination.