Quantitative Evaluation of Delamination in Composites Using Lamb Waves

3rd International Conference on Mechanical and Aeronautical Engineering

机械制造;航空航天工程

Michalcová, L.^1 ; Hron, R.^1

Strength of Structures Department, Materials, Technologies and NDT Group, VZLU - Czech Aerospace Research Center, Beranových 130, Prague

19905, Czech Republic^1

关键词: Aerospace structure;    Analytical equations;    Delaminated structure;    Propagation velocities;    Quantitative evaluation;    Structural health monitoring (SHM);    Ultrasonic guided wave;    Velocity dependence;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/326/1/012006/pdf
DOI  :  10.1088/1757-899X/326/1/012006

学科分类：航空航天科学

来源: IOP

【 摘 要 】

Ultrasonic guided wave monitoring has become very popular in the area of structural health monitoring (SHM) of aerospace structures. Any possible type of damage must be reliably assessed. The paper deals with delamination length determination in DCB specimens using Lamb waves. An analytical equation based on the velocity dependence on variable thickness is utilized. The group velocity of the fundamental antisymmetric A0 mode rapidly changes in a particular range of the frequency-thickness product. Using the same actuation frequency the propagation velocity is different for delaminated structure. Lamb wave based delamination lengths were compared to the visually determined lengths. The method of the wave velocity determination proved to be essential. More accurate results were achieved by tracking the maximum amplitude of A0 mode than the first signal arrival. These findings are considered as the basis for the damage evaluation of complex structures.