Issue 48

S. E. Oliveira et alii, Frattura ed Integrità Strutturale, 48 (2019Y) 249-256; DOI: 10.3221/IGF-ESIS.48.26 256 - Mechanical properties such as tensile strength and Young’s modulus are not very sensitive to drilling speed. Nonetheless, the high dispersion of the results for rotation-cutting speed seems to play a reduced effect on composite tensile strength and stiffness for both materials. In any case, above 3000 rpm a significant loss of stiffness was observed, which may be associated with the temperature developed in the machining process, which reached values above the glass transition temperature (Tg) of the resin. - Tensile stiffness increases significantly with the simultaneous increasing in the fiber content and length. In fact, tensile strength decreases with the increasing of the fiber content and length, in consequence of the poor fiber distribution and very high porosity for the too high fiber dosage composites. A CKNOWLEDGMENTS his research is sponsored by FEDER funds through the program COMPETE – Programa Operacional Factores de Competitividade – and by national funds through FCT – Fundação para a Ciência e a Tecnologia –, under the project PEst-C/EME/UI0285/2013. The authors thank the part of support to this investigation by the Brazilian agency CNPq, Conselho Nacional de Desenvolvimento Ciêntifico e Tecnológico, CsF. R EFERENCES [1] Shahrajabiana, H., Hadia, M. and Farahnakian, M. (2012). Experimental Investigation of Machining Parameters on Machinability of Carbon Fiber/Epoxy Composites, Int. J. of Eng. and Innov. Tech. (IJEIT), 2 (3), pp. 30-32. [2] Agarwal, G., Patnaik, A. and Sharma, R. K. (2014). Mechanical and thermo–mechanical properties of bi-directional and short carbon fiber reinforced epoxy composites. J. of Eng. Sci. and Tech., School of Engineering, 9(5), pp. 590 – 604. [3] Fu, S. Y., Lauke, B, Mäder, E., Yue, C. Y. and Hu, X. (2000). Tensile properties of short-glass-fiber- and short-fibber- carbon-reinforced polypropylene composites, Composites: Part A 31, pp.1117-1125. DOI: 10.1016/S1359-835X(00)00068-3. [4] Komanduri, R. (1997). Machining of fiber-reinforced Composite. Machining Science and Technology, 1 (1), pp. 113- 152. DOI: 10.1080/10940349708945641. [5] Davim, J. P. and Reis, P. (2004). Damage and dimensional precision on milling carbon fiber-reinforced plastics using design experiments. J. of Mat. Proc. Tech. 160, pp. 160–167. DOI: 10.1016/ j .jmatprotec.2004.06.003. [6] Park J.M., Lee S.I., Kim K.W. and Yoon D.J. (2001). Interfacial aspects of electrodeposited conductive fibers/epoxy composites using electro-micromechanical technique and nondestructive evaluation. J Colloid Interface Sci., 237, pp. 80–90. DOI: 10.1006/jcis.2001.7426. [7] Xu X., Zhou Z., Hei Y., Zhang B., Bao J. and Chen X. (2014). Improving compression-afterimpact performance of carbon–fiber composites by CNTs/thermoplastic hybrid film interlayer. Compos Sci Technol, 95, pp. 75–81. [8] Habib, S. and Okada, A. (2016), Influence of electrical discharge machining parameters on cutting parameters of carbon fiber-reinforced plastic. Mach. Sc. and Tech., 20(1), pp. 99-114. DOI: 10.1080/10910344.2015.1133914. [9] Yashiro, T., Ogawa, T. and Sasahara, H. (2013). Temperature measurement of cutting tool and machined surface layer in milling of CFRP. Int. J. of Machine Tools & Manufacture, 70, pp. 63–69. DOI: 10.1016/j.ijmachtools.2013.03.009. [10] Agarwal, H., Amaranath, A., Jamthe, Y. and Gururaja, S. (2015). An investigation of cutting mechanisms and strain fields during orthogonal cutting in CFRPs. Machining Science and Technology, 19 (3), pp. 416-439. DOI: 10.1080/10910344.2015.1051539. T