Abstract

Adhesive bonds are used extensively to join components of like or dissimilar materials in the aerospace and automotive industries due to the advantages of lower stress concentration and improved fatigue load behavior. With the extensive use of adhesive bonds, there is a need of inspection techniques to determine the bond states. Nondestructive evaluation (NDE) techniques based on linear ultrasound are effective to detect disbond states. However, there are several limitations in the linear-based ultrasonic NDE techniques, when they are used for the evaluation of weak bond states and kissing bond. It is difficult to detect these bonds because the received ultrasonic waves passing through weak bonds or kissing bonds are distorted, which makes ultrasonic techniques using linear characteristics improper. To evaluate these bonds, nonlinear ultrasonic methods can be applied by examining the acoustic nonlinear parameter (ANP). The nonlinear ultrasonic methods measure both the amplitudes of fundamental and higher harmonic components. Conventional nonlinear methods are based on transmission approaches that are not applicable in many scenarios due to limited access to both sides of a component. For this reason, one-sided methods are necessary, and a number of researchers have developed these nonlinear techniques including wave mixing techniques and pulse echo methods. Ju et al. showed that a two-wave mixing technique can be much more sensitive than linear reflection techniques in determining the effects of thermal aging on adhesive joints. Also, Jeong et al. showed that fluid ANP may be determined for immersion inspections after corrections for beam diffraction and attenuation based on a pulse echo method.

How to Cite:

Pyun, D., Koester, L., Barnard, D. & Bond, L. J., (2019) “Modeling and experiments of reflection based nonlinear ultrasonic inspections of adhesive bonds”, Review of Progress in Quantitative Nondestructive Evaluation .