Haldren Harold A, Perey Daniel F, Yost William T, Cramer K Elliott, Gupta Mool C
Charles L. Brown Department of Electrical and Computer Engineering, University of Virginia, Thornton Hall, 351 McCormick Road, Charlottesville, Virginia 22904, USA.
NASA Langley Research Center, 4 Langley Boulevard, Building 1230, Mail Stop 231, Hampton, Virginia 23681, USA.
J Acoust Soc Am. 2019 Mar;145(3):1609. doi: 10.1121/1.5094764.
As modern aerospace and automotive designs continually strive for higher performance, and thus rely on advanced composite structures where adhesive bonding is a preferred method of joining, the need for a robust quantitative nondestructive bond strength measurement method has increased. As such, advanced nondestructive evaluation methods have been researched for increased sensitivity to weak interfacial bonding and ultimately to detect "kissing" bonds. In this work, a phase-based method for interrogating bonded joints and detecting weak adhesion is developed by using swept-frequency phase measurements of ultrasonic waves reflected from an adhesive joint and modeling adhesive interfaces as a distributed spring system. The method's sensitivity to bond strength is explored by ultrasonic phase evaluation of tri-layer joints with bond quality varied by controlling ultraviolet light exposure and extracting interfacial stiffness constants of the bonds. Mechanical tensile tests found each joint failed adhesively, allowing a linear correlation to be drawn between interfacial stiffness and tensile strength, consistent with previous theoretical research. The ultrasonic phase measurement method identifies intermediate bond strengths, rather than simply detecting good or bad bonds. This technique has the potential for the verification of bond quality in lightweight aerospace and automotive designs utilizing advanced composite structures with adhesive attachments.
随着现代航空航天和汽车设计不断追求更高的性能，因此依赖于先进的复合结构，其中粘接是一种首选的连接方法，对一种可靠的定量无损粘结强度测量方法的需求也在增加。因此，人们研究了先进的无损评估方法，以提高对弱界面粘结的灵敏度，并最终检测出“微接触”粘结。在这项工作中，通过对从粘接接头反射的超声波进行扫频相位测量，并将粘接界面建模为分布式弹簧系统，开发了一种用于检测粘接接头和检测弱粘结的基于相位的方法。通过对三层接头进行超声相位评估来探索该方法对粘结强度的灵敏度，通过控制紫外线照射来改变粘结质量，并提取粘结的界面刚度常数。机械拉伸试验发现每个接头均发生粘结失效，从而可以在界面刚度和拉伸强度之间建立线性关系，这与先前的理论研究一致。超声相位测量方法能够识别中等粘结强度，而不是简单地检测粘结的好坏。该技术有可能在利用带有粘接附件的先进复合结构的轻质航空航天和汽车设计中验证粘结质量。
