基于超声热波方法的铝合金应力腐蚀裂纹检测与识别

Detection and Recognition of Aluminums Alloy Stress Corrosion Crack by Ultrasonic Thermal Wave Method

针对飞行器结构中应力腐蚀裂纹的快速高效检测需求,采用超声红外热波方法进行了检测试验研究。在改进WOL铝合金材料应力腐蚀裂纹试件上,改变超声激励位置在裂纹尖端延伸方向并沿裂纹接触面的切线方向上、在裂纹尖端延伸方向并垂直于裂纹接触面上以及在试件开口延伸方向并垂直于裂纹接触面上,获得了不同激励位置下试件的表面温度场分布,通过提取裂纹方向上的线温,实现了对裂纹的定量识别。结果表明:超声红外热波技术能够快速准确地检测到铝合金应力腐蚀裂纹,将超声波激励源布置在裂纹尖端延伸方向并垂直于裂纹接触面上时,能够更好地激发裂纹缺陷。

For the needs of fast and efficient detection of stress corrosion crack in aircraft structure, the ultra- sonic infrared thermal wave method was applied for the detection research. An improved aluminum alloy WOL stress crack specimen was detected by changing the ultrasonic excitation position respectively at the crack tip extension di- rection that along the crack surface tangential direction, at the crack tip extension direction and perpendicular to the crack contact surface, and at the crack hatch extension direction and perpendicular to the crack contact surface, obtained the surface temperature distribution of the specimen under different excitation positions. The crack was quantitatively identified by picking-up and anglicizing the line temperature along the crack direction. The results show that： the ultrasonic thermal wave method can quickly and accurately detected aluminum alloy stress corrosion crack, and the crack can be better detected by locating the ultrasonic excitation at the crack tip extension direction and perpendicular to the crack contact surface.