Issue 47

J. P. Manaia et alii, Frattura ed Integrità Strutturale, 47 (2019) 82-103; DOI: 10.3221/IGF-ESIS.47.08 102 exhibiting high deformation before failure (ductile failure). The inner layer shows a more ductile behaviour than at α = 90°. Different fracture morfologies are observed, when compared with α = 90°. The fracture becomes more ductile and less homogeneous, with more formation propensity of longer fibrous surface. Also, with the temperature increase, fracture becomes more homogenous. SEM images of fracture mechanisms under pure shear, α = 0°, leaves a relatively smooth fracture surface and orientated geometry. In general, it is observed that the fibrils are oriented towards the shear direction. With the temperature increase, fracture becomes more homogenous in the case of PA 6 and slightly inhomogeneous for PP and PA 6. A CKNOWLEDGMENTS he present research work has been financial supported through the NORTE-01-0145-FEDER-000022 - SciTech - Science and Technology for Competitive and Sustainable Industries, I&D project co-funded by Programa Operacional Regional do Norte ("NORTE2020"), through the Fundo Europeu de Desenvolvimento Regional (FEDER) and by FCT (Fundação para a Ciência e a Tecnologia) under a PhD grant with reference PD/BD/52346/2013 are gratefully acknowledged. This work was funded by National Funds through FCT – Fundação para a Ciência e a Tecnologia in the scope of project MITP-TB/PFM/0005/2013. R EFERENCES [1] Sedighiamiri, A., Govaert, L.E., Van Dommelen, J.A.W. (2011). Micromechanical Modeling of the Deformation Kinetics of Semicrystalline Polymers, J. Polym. Sci. Part B Polym. Phys., 49(18), pp. 1297–1310. DOI: 10.1002/polb.22297. [2] Galeski, A. (2003). Strength and Toughness of Crystalline Polymer Systems, Prog. Polym. Sci., 28(12), pp. 1643–1699. DOI: 10.1016/j.progpolymsci.2003.09.003. [3] Narisawa, I., Ishikawa, M. (1990). Crazing in Semicrystalline Thermoplastics, Crazing Polym. 2(2), pp. 353–391. DOI: 10.1007/BFb0018025. [4] Bai, Y. (2008). Effect of Loading History on Necking and Fracture, PhD Thesis, (2000), pp. 1–262. [5] Bridgman, P.W. (1923). The Compressibility of Thirty Metals as a Function of Pressure and Temperature, Proc. Am. Acad. Arts Sci., 58(5), pp. 165–242. [6] Estevez, R., Tijssens, M.G.A., Van Der Giessen, E. (2000). Modeling of the Competition Between Shear Yielding and Crazing in Glassy Polymers, J. Mech. Phys. Solids, 48(12), pp. 2585–2617. DOI: 10.1016/S0022-5096(00)00016-8. [7] Tijssens, M.G.A., Van Der Giessen, E., Sluys, L.J. (2000). Modeling of Crazing Using a Cohesive Surface Methodology, Mech. Mater., 32(1), pp. 19–35. DOI: 10.1016/S0167-6636(99)00044-7. [8] Hachour, K., Zaïri, F., Naït-Abdelaziz, M., Gloaguen, J.M., Aberkane, M., Lefebvre, J.M. (2014). Experiments and Modeling of High-Crystalline Polyethylene Yielding Under Different Stress States, Int. J. Plast., 54, pp. 1–18. DOI: 10.1016/j.ijplas.2013.06.004. [9] Mark, J.E. (2009). Polymer Data Handbook, Oxford University Press. [10] Faleskog, J., Barsoum, I. (2013). Tension-Torsion Fracture Experiments - Part I: Experiments and a Procedure to Evaluate the Equivalent Plastic Strain, Int. J. Solids Struct., 50(25–26), pp. 4241–4257. DOI: 10.1016/j.ijsolstr.2013.08.029. [11] Boisot, G., Laiarinandrasana, L., Besson, J., Fond, C., Hochstetter, G. (2011). Experimental Investigations and Modeling of Volume Change Induced by Void Growth in Polyamide 11, Int. J. Solids Struct., 48(19), pp. 2642–2654. DOI: 10.1016/j.ijsolstr.2011.05.016. [12] Laiarinandrasana, L., Besson, J., Lafarge, M., Hochstetter, G. (2009). Temperature Dependent Mechanical Behaviour of PVDF: Experiments and Numerical Modelling, Int. J. Plast., 25(7), pp. 1301–1324. DOI: 10.1016/j.ijplas.2008.09.008. [13] Dunand, M., Mohr, D. (2011). Optimized Butterfly Specimen for the Fracture Testing of Sheet Materials Under Combined Normal and Shear Loading, Eng. Fract. Mech., 78(17), pp. 2919–2934. DOI: 10.1016/j.engfracmech.2011.08.008. [14] Doyoyo, M., Wierzbicki, T. (2003). Experimental Studies on the Yield Behavior of Ductile and Brittle Aluminum Foams, Int. J. Plast., 19(8), pp. 1195–1214. DOI: 10.1016/S0749-6419(02)00017-7. [15] Arcan, M., Hashin, Z., Voloshin, A. (1978). A Method to Produce Plane-Stress States with Applications to Fiber- T