Abstract: According to the characteristics of the resin matrix composites with high sonic attenuation, the high energy ultrasonic excitation technology and the signal enhancement technology of the receiving end are used to test the material. The excitation voltage, damping resistance and waveform of the excitation signal are analyzed, the excitation mode of bipolar square wave pulse string is put forward, the amplifier circuit of the receiving end is designed, and the testing parameters are determined. The results show that the excitation voltage is proportional to the ultrasonic amplitude when less than the breakdown voltage. When other conditions are unchanged, the ultrasonic signal with the largest amplitude can be excited when the damping resistance of the ultrasonic instrument is adjusted to the maximum. Under the same condition, the amplitude of ultrasonic wave excited by different waveform sequence from high to low is bipolar square pulse string, single square wave, sharp pulse. The proposed method can test the resin matrix composites with high sonic attenuation, as well as the defects not bigger than 5 mm.

Key words: attenuation, ultrasonic test, excitation, composite