Air- coupled ultrasonic testing of CFRP rods by means of guided waves

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• 作者：Rymantas Kaž ; ys ; Renaldas Raiš ; utis ; Egidijus Ž ; ukauskas ; Liudas Maž ; eika ; Alfonsas Vladiš ; auskas
• 关键词：Air-coupled ultrasonic testing ; CFRP rod ; Guided ultrasonic waves ; Ultrasonic non-destructive testing
• 刊名：Physics Procedia
• 出版年：2010
• 出版时间：1 January 2010
• 年：2010
• 卷：3
• 期：1
• 页码：185-192
• 全文大小：1373 K

文摘

One of the most important parts of the gliders is a lightweight longeron reinforcement made of carbon fibre reinforced plastics (CFRP) rods. These small diameter (a few millimetres) rods during manufacturing are glued together in epoxy filled matrix in order to build the arbitrary spar profile. However, the defects presenting in the rods such as brake of fibres, lack of bonding, reduction of density affect essentially the strength of the construction and are very complicated in repairing. Therefore, appropriate non-destructive testing techniques of carbon fibber rods should be applied before gluing them together.

The objective of the presented work was development of NDT technique of CFRP rods used for aerospace applications, which is based on air- coupled excitation/reception of guided waves.

The regularities of ultrasonic guided waves propagating in both circular and rectangular cross-section CFRP rods immersed into water were investigated and it was shown that the guided waves propagating along sample of the rod create leaky waves which are radiated into a surrounding medium. The ultrasonic receiver scanned over the rod enables to pick-up the leaky waves and to determine the non-uniformities of propagation caused by the defects.

Theoretical investigations were carried out by means of numerical simulations based on a 2D and 3D finite differences method. By modelling and experimental investigations it was demonstrated that presence of any type of the defect disturbs the leaky wave and enables to detect them. So, the spatial position of defects can be determined also. It was shown that such important defects as a disbond of the plies essentially reduce or even completely suppress the leaky wave, so they can be detected quit easily.