Characterization of the damage mechanism in CFRP composites under mode I based on comprehensive analysis of AE signals

Abstract

This study utilises several methods centred on acoustic emission (AE) waveform characteristics to conduct in-depth analysis of the damage mechanism of composite materials under mode I. Combined with the peak frequency statistics and continuous wavelet transform (CWT) of AE signals, three damage modes of laminated composites during loading are identified. The cumulative energy of three damage modes separated by variational modal decomposition (VMD) is used to characterize their damage evolution process. Based on the findings, delamination and fiber–matrix debonding are proven to be the dominant damage mechanisms for mode I. The comprehensive analysis results from AE's accumulated energy, peak frequency distribution, CWT, VMD, and sentry function can accurately detect the onset time of delamination in laminates. The equivalent crack length is calculated by the load value determined at the initial time of delamination, and the strain energy release rate calculated by the load value and crack length at this time is used as the interlaminar fracture toughness value of mode I. This research method will provide a new idea for the damage tolerance analysis of mode I delamination in laminated structures.

Keywords:

• Acoustic emission
• continuous wavelet transform
• variational modal decomposition
• damage mechanism
• mode I

Author contributions

Wenqin Han: conceptualization, methodology, and writing – original draft. Bin Hu: software and investigation. Jinyu Zhou: funding acquisition. Qinghe Shi: data curation and writing – review and editing. Yingming Wang: supervision and formal analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by National Natural Science Foundation of China under Contracts Nos. (52075232, 12102156, and 52205157).