Quasi-static indentation damage and residual compressive failure analysis of carbon fiber composites using acoustic emission and micro-computed tomography

Abstract

In present research, the internal damage evolution and failure characteristics of carbon fiber woven composites under indentation and residual compressive loads were studied by using acoustic emission technology and X-ray micro-computed tomography. Real-time acoustic emission signals originating from internal damage of composites under applied loads were obtained and analyzed by the k-means clustering algorithm. Moreover, the internal damage characteristics were observed by the reconstructed three-dimensional model and the slice images of composite specimens. The results showed that the higher the indentation force reading, the more acoustic emission signals with high amplitude and frequency (over 300 kHz) are generated. Furthermore, the early acoustic emission signals with high-frequency were observed under residual compressive loads. It can be attributed to serious failures of fibers with the increase of static indentation loads. In addition, the internal damages such as delamination, debonding, crack and fiber breakage can be clearly characterized by micro-computed tomography and scanning electron microscopy observation. The complementary technology combing acoustic emission with micro-computed tomography can provide a better understanding of internal damages and evolution behaviors of the composites.

Effects of various porosities on the damage evolution behavior of carbon fiber/epoxy composites using acoustic emission and micro-CT

“…Frequency is another important characteristic parameter of AE signals, and different frequency ranges can be associated with different damage modes. 40 According to previous researches, 41,42 the frequency range less than 150 kHz (low frequency), 150-300 kHz (middle frequency), and over 300 kHz (high frequency) may be associated with matrix cracking and delamination, fiber/ matrix debonding, and fiber damage, respectively. The distribution of frequency and bending load varied with This phenomenon may be associated with voids in fiber bundles.…”

Comparison of off-axis angle on the low velocity impact behaviors for carbon-fiber-reinforced polymer laminates

“…Differences in impact and CAI responses of laminates are mainly determined by impact damage created at the damage threshold. Zhang et al 18 studied internal damage evolution, failure characteristics, and residual compressive loads of woven carbon-fiber composites after different indentations using AE technology and X-ray Microcomputed tomography. They established the relationship between AE signal frequency and damage modes, and verified their results using Micro-CT technology.…”