功率超声激励非线性振动测试装置设计与实验研究

针对超声热成像检测中非线性振动问题,设计了激光探头夹持装置,构建了一套非接触式激测振系统,开展了功率超声激励下变幅杆振动特性响应试验,验证激光测振系统的有效性。在此基础上,开展了功率超声激励下试件振动特性影响试验,重点研究了耦合剂和粗糙度对振动特性的影响,结果表明：耦合剂能增强缺陷生热是因为提高了超声能量的传递效率,增大试件的振动幅值,促进了试件的振动,这也为超声热成像检测时选用适宜的耦合剂提供了一种试验途径。同时,一定程度的粗糙度可以起到类似耦合剂的作用,增强超声的能量传递,促进试件的振动。

Measurement device design and experiment of non-line vibration under power ultrasonic excitation

Aiming to the problem of non-line vibration in ultrasonic infrared thermography, the holding device for laser probe is designed and a non-contact laser vibration measurement system is established. Then, the vibration response experiment of horn under power ultrasonic excitation is carried out to validate the effectiveness of the laser vibration measurement system. On this basis, the vibration response experiment of specimen under power ultrasonic excitation is carried out, focusing on the effects of couplant and roughness on vibration characteristics. The obtained results show that the couplant can enhance defect heating is because the couplant improves the transmission efficiency of power ultrasonic, strengths the vibration amplitude of specimen and facilitates the vibration of specimen, which also offers a testing way to choose the suitable couplant in ultrasonic infrared thermography. Meanwhile, a certain degree roughness can act as the couplant to enhance transmission efficiency of power ultrasonic and to strength the vibration of specimen.