Document Type : Research Paper

Authors

1 Department of Mechanical Engineering, Islamic Azad University, Science and Research Branch, Tehran, Iran.

2 Faculty of Materials & Manufacturing Technologies, Malek Ashtar University of Technology, Tehran, Iran.

3 Department of Mechanical Engineering, Emam Hossein University, Tehran, Iran.

Abstract

Drilling process of Fibers Glass-epoxy composites is always associated with defects such as interlayer delamination phenomenon. This phenomenon reduces the strength of composite panels. In this study, to minimize this defect, the effective parameters including feed rate, tool diameter, thickness, edge tool angle, rotational speed, orientation fibers and coolant were studied. The number of experiments was specified based on Taguchi's design of experiments method and Experimental study was performed on the drilling process of the composite to evaluate the amount of delamination. Then holes were scanned by a Video Measuring machine(VMM) and amount delamination in them has been calculated by considering hole diameter. The collected data were used to statistically analyze and optimize the drilling parameters using variance analysis (ANOVA). The results showed that feed rate with a 29.6% and rotational speed with 24% had greatest influence on the delamination, so that with increasing the feed rate delamination was increased and with increase in rotational speed, delamination is first increased and then decreased. Also to investigation of the effect of delamination on the tensile strength of composite and stress concentration coefficient, specimens were subjected to tensile test. The results showed that with increasing delamination, the average tensile strength and stress concentration coefficient of perforated parts compared to healthy specimen( without hole), 34% decreased and 51.66% increased respectively. Also with 1.22 times the delamination compared to the delamination of initial sample, tensile strength 6.5% decreased and stress concentration coefficient 6.9 increased.

Keywords

[1] Sheikh-Ahmad J, Y., “Machining Of Polymer Composites”, Chapter6, Nontraditional Machining of FRPs, Springer, 2012.
[2] Singh, I., Bhatnagar, N. and Viswanath, P. “Drilling of Unidirectional Glass Fiber Reinforced Plastics: Experimental and Finite Element Study”, Materials and Design, Vol. 29, No. 2, pp. 546–553. 2008.
[3] Khashaba, U. A., “Delamination in Drilling Polymeric Composites: a Review. In: Paulo Davim J, editor. Drilling of Composite Materials”,        Nova Science Publishers., Inc. 2009.
[4] Karimi, N. Z., Heidary, H. and Ahmadi, M., “Residual Tensile Strength Monitoring of Drilled Composite Materials by Acoustic Emission”, In Persian, Material and Design, Vol. 40, pp. 229–236, 2012.
[5] Ogawa, K., Aoyama, E., Inoue, H. and Gunjima, M., “Investigation on Cutting Mechanism in Small Diameter Drilling for GFRP (Thrust Force and Surface Roughness at Drilled Hole Wall)”, Composite. Structures, Vol. 38, No. 1-4, pp. 343-350, 1997.
 [6] Tsao, C. C., Hocheng, H., and Chen, Y. C., “Delamination Reduction in Drilling Composite Materials by Active Backup Force”, Manufacturing Technology, Vol. 61, N0. 1, pp. 91-94, 2012.
[7] Jamal sheikh , Ahmad, “Machining of Polymer Composites”, The petroleum  institute department of mechanical engineer in united arab Emirates, chapter 5, pp. 187- 219, 2009.
[8] Taskesen, A. and Kutukde. K., “Analysis of Drilling Temperature When Drilling B4C Reinforced Aluminum Composites”, Industrial Design Engineering, Gazi university, Ankara, 2014.
[9] Sahami poor Dehghan, M. and Heidary, H., “ Experimental Study in Drilling Composite Pipes Manufactured by Filament Winding Process Using Full Factorial Design Method”, In Persian, Amirkabir J. Mech. Eng., Vol. 50, No. 3,  pp. 489-504, 2018.
[10] Mohammadi, B., Kazemi, A. and Ghasemi, R., “Damage Analysis of Holed Composite Laminates using Continuum Damage Mechanics”, In Persian, Journal of science and technology of composite of composite(JSTC), Vol. 2, No. 3, pp. 23-34, 2015.
[11] Zuluaga,W., “Effect of cycle loading Amplitude Tension-Tension on Composite Laminated Plates with initial Delamination”, A Thesis presented to the Faculty of California polytechnic state University.,2013.
[12]. Sonbaty, El., khashaba, U. A. and Machaly, T., “Factors Affecting the Machine Ability of GFR/EPOXY Composites”, Composite Structure, Vol. 63, No. 3-4, pp. 329-338, 2004.
[13] Amini, S. Baraheni, M. and Moeini Afzal, M., “Statistical Study of the Effect of Various Machining Parameters on Delamination in Drilling of Carbon Fiber Reinforced Composites”, In Persian, Journal of Science and Technology of Composites, Vol. 5, No. 1, pp. 41-50, 2018.
[14] Capello,E., “Workpiece Damping and its Effects on Delamination Damage in Drilling thin Composite Laminates”, Journal of Materials Processing Technology, Vol. 148, No. 2, pp. 186-19, 2004.
[15] Hakimi, E. and Amini, S., “Study of Delamination in the Process Helical Milling of Carbon Fiber-Reinforced Polymer Composite”, In Persian, Journal of Science and Technology of Composites, Vol. 2, No. 4, pp. 51-58, 2016.
[16] Saberi, M. Niknam, S.A. and Hashemi, R., “On the Effects of Cutting and Lubrication Parameters on the Surface Quality and Cutting Forces in Machining Ti-MMC-Experimental and Frequency Assessment”, In Persian, Journal of Science and Technology of Composites, Vol. 6, No. 1, pp. 143-150, 2019.
[17] Agwa, M. A. and Megahed, A. A., “New Nonlinear Regression Modeling and Multi-Objective Optimization of Cutting Parameters in Drilling of GFRE Composites to Minimize Delamination”, Polymer Testing, Vol. 75, pp. 192-204, 2019.
[18] Upputuri, H. B. and Nimmagadda, V. S., “Optimization of Drilling Process Parameters used in Machining of Glass Fiber Reinforced Epoxy Composite”, Materials Today: Proceedings, Vol. 23, No. 3, pp. 594-599, 2020.
 [19]. Davim, j. P., Reis, P., and Antonio, C., "Drilling Fiber Reinforced Plastics (FRPs) Manufactured by Hand Lay-up: Influence of Matrix (Viapal VUP 9731 and ATLAC 382-05”, Journal of Materials Processing Technology, Vol. 1155-156, No. 30, pp. 1828-1833, 2004.