Monitoring the initiation and growth of delamination in composite materials using acoustic emission under quasi-static three-point bending test

Abstract

Control and optimization of machining processes are important issues affecting the development of productivity. Monitoring systems have become indispensable in the evaluation of materials during machining. In this paper, the path toward the delamination-free drilling of glass/epoxy composite material is established using some novel methods based on acoustic emission features. Acoustic emission monitoring with three techniques, sentry function, acoustic emission energy distribution, and acoustic emission count distribution, are developed to detect and realize the critical force at the onset of delamination process on glass/epoxy composite materials. The three-point bending test simulates thrust force, the most effective factor in delamination, throughout the process of drilling without backup plate. Sentry function is regarded as a new method based on the combination of AE information and mechanical behavior of composite materials. The sentry function was used to study the initiation and growth of delamination process. Two types of specimen with different layups, woven [0, 90] s and unidirectional [0] s , leading to different levels of damage evolution, were studied. Results show that AE parameters and sentry function method are useful tools for the examination of initiation and the growth of delamination during drilling process and can help to avoid delamination damage while drilling.

Effect of PVDF nanofibers on the fracture behavior of composite laminates for high-speed woodworking machines

“…As stated by previous studies [27][28][29][30][31][32][33][34][35][36] AE signal generated from each failure mode of laminated composites, such as matrix cracking, debonding and fiber breakage, has its specific ranges of amplitude and duration. Lower duration and amplitude values are related to matrix cracking, while the higher values are linked with fiber breakage.…”

“…AE signal is a spontaneous transient energy released by different damage sources such as matrix cracking, fiber breakage during the loading [27]. This technique was used to distinguish the failure modes in laminated composite materials and there was a promising applicability of this method [28][29][30][31][32][33][34]. Their results presented a capable applicability of AE parameters for classification of damage mechanisms in laminated composite materials.…”

Acoustic emission monitoring of thin ply hybrid composites under repeated quasi-static tensile loading

“…Successful results have been reported for damage characterization of composite laminates using the AE parameters. Different frequency, energy and amplitude ranges were observed for different damage mechanisms such as fibre breakage, matrix cracking and delamination [26][27][28][29][30][31][32].…”

Analysis of the damage mechanisms in mixed-mode delamination of laminated composites using acoustic emission data clustering

“…Furthermore, three dominant damage mechanisms (matrix-cracking, fiber-matrix debonding and fiber breakage) take place during delamination while these different damage mechanisms generate different AE parameters. Additionally, the achieved results specified that higher frequencies and amplitudes emerging in the tests were related to fiber breakage while lower ranges contributed to matrix cracking and fiber-matrix debonding damages [2,8,9,10].…”

“…Until now, some researchers discriminated the AE signatures of damage mechanisms in composite materials [7][8][9][10][11][12]. Their results showed that AE technique is a capable tool for characterization of damage mechanisms in thermoplastic and thermoset laminated composite materials.…”