Fatigue life reduction of GFRP composites due to delamination associated with the introduction of functional discontinuities
Introduction
Fiber reinforced polymer-matrix composite materials are widely used due to favorable engineering properties such as corrosion resistance, high strength and stiffness with low specific weight. As such, composites offer advantages for the design of aerospace components. Safety critical aerospace components must also satisfy stringent fatigue fracture performance requirements to be considered. To be a candidate material within a systematic design program, composites must be able to achieve adequate safety margins. This issue makes composites interesting field for researchers [[1], [2], [3], [4], [5]]. Of critical importance in fatigue performance is the existence of stress-raising geometric discontinuities that are, of course, essential if a component is to be integrated into an assembly.
The introduction of a hole into a composite laminate can result in subsequent fatigue loading to introduce multiaxial stresses into the laminate [6]. Given the prevalence of holes in aerospace parts, investigating the impact of holes on fatigue performance is of critical importance when considering safe function.
Section snippets
Prior investigations
Prior published investigations into fatigue behavior of drilled composites are outlined. Belmonte and colleagues [7] investigated the influence of fiber volume fraction on the fatigue behavior of short glass fiber reinforced polyamide (PA66) where specimens with fiber content of between 0% and 50% were drilled and tested. Field Emission Scanning Electron Microscopy (FESEM) was used to investigate the influence of fiber content specimen damage due to fatigue loading. Their results concluded that
Materials
The studied materials were unidirectional (GF 12/200 DLN) and woven (VV 770), with IMP503 resin, prepreg glass/epoxy supplied by G. Angeloni Srl. Fiber volume fraction was 20.16% for unidirectional and 28.23% for woven specimens. They were vacuumed and cured under 125 °C for 1 h after manufacturing, composite plates' quality were checked by the ultrasonic C-scan method. To manufacture specimens, the plates were cut by water jet machine with dimensions of 170 × 20 mm2 and thickness of 5 mm
Experimental results and analysis
This study shows when feed rate increases and cutting speed reduces, Fda increases. In addition, the woven specimens were found to be more resistant to delamination than the unidirectional specimens with the same drilling parameters. Table 2 shows the adjusted delamination factors by diverse drilling parameters in the woven and unidirectional specimens. Last column in this table shows difference in amount of Fda for unidirectional and woven specimens. It is obvious that by improving drilling
Concluding remarks
This paper has identified the importance of drilling parameters (feed rate and cutting speed) selection and their effect on the extent of delamination, static strength and fatigue life of composite materials. It was found that the extent of cyclic-load induced delamination decreases as the hole cutting speed increases or as the feed rate decreases.
Quasi-static three point bending tests showed that the static strength of the high speed drilled specimens using different cutting speeds and feed
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Acknowledgments
The authors wish to thank the Department of Mechanical Engineering at Amirkabir University of Technology, Tehran, Islamic Republic of Iran; the Department of Industrial Engineering at Bologna University, Italy; and, the Department of Mechanical Engineering at the University of Melbourne, Australia, for providing facilities and resources for this study.
References (32)
- et al.
Size dependent free vibration analysis of multicrystalline nanoplates by considering surface effects as well as interface region
Int J Mech Sci
(2014) - et al.
Notch insensitive orientation-dispersed pseudo-ductile thin-ply carbon/glass hybrid laminates
Compos Appl Sci Manuf
(2018) - et al.
Clustering of interlaminar and intralaminar damages in laminated composites under indentation loading using Acoustic Emission
Compos B Eng
(2018) - et al.
Considering damages to open-holed composite laminates modified by nanofibers under the three-point bending test
Polym Test
(2018) - et al.
Size-dependent static characteristics of multicrystalline nanoplates by considering surface effects
Int J Mech Sci
(2014) - et al.
Damage initiation and evolution in short fiber reinforced polyamide under fatigue loading: influence of fiber volume fraction
Compos B Eng
(2017) - et al.
Progressive damage assessment of centrally notched composite specimens in fatigue
Compos Appl Sci Manuf
(2015) - et al.
A review of mechanical drilling for composite laminates
Compos Struct
(2012) - et al.
Effects of high speed in the drilling of GFRP: evaluation of the delamination factor
Int J Mach Tool Manufact
(2008) - et al.
Delamination analysis in high speed drilling of carbon fiber reinforced plastics (CFRP) using artificial neural network model
Mater Des
(2008)
Drilling of carbon fiber-reinforced composite material at high speed
J Compos Mater
Delamination analysis in high speed drilling of carbon fiber reinforced plastics (CFRP) using artificial neural network model
Mater Des
Drilling of GFRP composites for minimising delamination effect
Mater Today: Proc
A novel approach based on digital image analysis to evaluate the delamination factor after drilling composite laminates
Compos Sci Technol
Correlation of acoustic emission with finite element predicted damages in open-hole tensile laminated composites
Compos B Eng
Cited by (22)
Damage detection of FRP structures using the electrical resistance response of MWCNTs networks in a PDMS film substrate
2024, Sensors and Actuators A: PhysicalMultiscale progressive damage model for plain woven composites
2023, International Journal of Mechanical SciencesA semi-analytical model for failure analysis of delaminated composites under fatigue loading
2023, Composite StructuresGMDH-Kalman Filter prediction of high-cycle fatigue life of drilled industrial composites: A hybrid machine learning with limited data
2023, Expert Systems with ApplicationsInfluence of deposition rates on the mode I fracture toughness of in-situ consolidated thermoplastic composites
2023, Composites Part B: EngineeringCitation Excerpt :Thermoset-based composites are the preferred solution in many demanding engineering applications but often lack the desired resistance to delamination growth under static and fatigue loading [1–5].