Detection of impact damage and fibre texture on CFRP using open-ended waveguide probe

We propose a novel method using open-ended rectangular waveguide probe operating in K-band (18-26.5GHz) for inspecting impact damage and fibre texture of the CFRPs. Reflection coefficients are measured by means of vector network analyser (VNA) at different points in X and Y directions (C-scan). Three different energy impact samples: 4J, 6J, and 10J are tested. The optimal scanning step sizes with certain lift-off for inspection of impact damage and fibre texture are studied. Principal component analysis (PCA) method is applied to analyse and extract features from measurement results for surface texture and impact damage evaluation. In this study, we identify the optimal scanning step sizes with a specific lift-off for revealing fibre texture, features for damage inspection, and detectability of low impact damage using PCA and spectrum analysis.