High resolution X-ray computed tomography: A versatile non-destructive tool to characterize CFRP-based aircraft composite elements

Elena Dilonardo, Michele Nacucchi, Fabio De Pascalis, Mauro Zarrelli, Cinzia Giannini - Institute of Crystallography (IC), CNR, Bari, Italy ;I.M.A.S.T, Napoli, Italy ; ENEA, Brindisi, Italy ; Institute of Polymers, Composite and Biomaterials (IPCB), CNR, Portici, Italy

The aim of the current study is to propose a versatile, non-destructive inspection strategy to evaluate the structure of two different aircraft carbon fibre reinforced polymer (CFRP) -based composite configurations, which are widely used for structural elements, respectively layered composite and sandwich structure. X-ray computed tomography (CT) has been used as a flexible method for assessment of porosity levels in CFRP components in both types of configuration, permitting to investigate the volume distribution of the individuated pores/voids, giving an interactive 3D exploration and quantitative analysis of porosity by the complete 3D volume rendering of the analysed composites. Moreover, specific data analysis could supply detailed information on size, shape and position of pores or defect or misalignment which could be a valuable indication for damage tolerant design methodology or local stress analysis. This presented non-destructive approach based on CT can be a good alternative to standard destructive methods based on the acid digestion or 2D microscopy for porosity evaluation in composite, especially for severe stressed element in aerospace structure. Of course, the high resolution X-ray CT cannot substitute the ultrasounds test for analysing full scale components, but it can be complementary to it to provide accurate quantitative results on small samples used as references.

How Amira-Avizo Software is used

“The Avizo 8 Fire Software was used for the image processing of the datasets, segmentation and analysis procedures. It was chosen for the versatility and feasibility in the data processing and images analysis; indeed, it permitted not only to visualize but also, after an accurate segmentation procedure of the grayscale histogram relative to the X-ray CT acquired images, to obtain a specific data analysis, as, in the reported case, the labelling of pores, and a mathematical and statistical analysis of the detected pores, evaluating their shape, their volume, etc. and visualizing them in the 3D reconstructed analysed object.”¬†Elena Dilonardo, PhD.