Interlaminar fatigue crack growth behavior of MWCNT/carbon fiber reinforced hybrid composites monitored via newly developed acoustic emission method

Abstract

Abstract. The aim of this research was the investigation of the effect of carbon nanotube addition on the mode I interlaminar fatigue properties of carbon fiber reinforced composites. The authors developed a localization methodology to track the interlaminar fatigue crack front using the acoustic emission (AE) technique. According to the test evaluation the carbon nanotube reinforcement decreased the crack propagation rate by 69% compared to the composite containing no nanotubes. Besides that, the fatigue life also increased significantly, the nanotube reinforced composite could withstand 3.8-times more cycles to failure than the unfilled matrix composite.

Prediction of delamination growth in carbon/epoxy composites using a novel acoustic emission-based approach

“…Next, crack length during delamination of the specimens is determined by means of the recorded AE parameters. Previous studies [19][20] demonstrated the applicability of AE to localize the delamination growth in the laminated composite specimens under mode I and compression loading conditions. In this paper, to predict the delamination length, two procedures are utilized: 1) localization of the detected AE signals sources and 2) determining a relationship between the cumulative AE energy and the length of crack.…”

Prediction of quasi-static delamination onset and growth in laminated composites by acoustic emission

“…The function which is used for this combination is called sentry function. As indicated by Eq 5, the sentry function is stated in the logarithm form of the ratio between mechanical and acoustical energies [18]:…”

“…There are some studies about to investigate the delamination damage in composite materials by use of AE. Romhany et al [18] offered the localization algorithm based on AE signals to predicted of delamination growth in the carbon/epoxy specimens under mode I loading condition. The results show that AE method capables predicted growth of the delamination during the tests.…”

Prediction of delamination growth in laminated composites using acoustic emission and Cohesive Zone Modeling techniques

“…They used AE to monitor microscopic events such as matrix cracking, fiber breakage, etc., during the delamination. In addition, AE was used to predict the delamination growth in laminated composite materials [22][23]. The results showed that AE method is capable of predicting delamination growth during the tests.…”