Characterisation of anomalies embedded in graphite fibre reinforced aluminium composite by chirplet parameters

Abstract

To characterise anomalies embedded in graphite fibre reinforced aluminium matrix composite, chirplet parameters of ultrasonic signals were obtained by chirplet signal decomposition method. It was confirmed that the parameters of decomposed chirplets can represent the characteristic of ultrasonic signals in time and frequency domains compared with conventional time and frequency analysis method. Chirplet parameters were used to identify three types of anomalies embedded in graphite fibre reinforced aluminium matrix composite. The variations of centre frequency and phase of three anomalies were interpreted by frequency dependent attenuation coefficient of composite and frequency dependent reflection coefficient of thin anomalies embedded in composite.