PSI - Issue 2_B

Moslem Shahverdi et al. / Procedia Structural Integrity 2 (2016) 1886–1893 Shahverdi et al./ Structural Integrity Procedia 00 (2016) 000–000

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Finite element models were developed in order to validate the “extended global method”. Analysis of the FE results showed that the mode-mixity ratios obtained from FE models is a function of the crack extension length when the crack propagates in a bi-material interface. Introduction of a resin interlayer with the average properties of the adjacent layers of the interface solved this problem. Zero-thickness cohesive elements were used to model the fiber bridging zone. The bridging zone was modeled with cohesive elements and an exponential traction-separation law. The fiber bridging contribution decreased as G I / G II decreased. Comparison of the G tot values estimated/calculated according to the “extended global method”, the experimental compliance method and FE modeling showed good agreement between the three approaches. Acknowledgements This work was supported by the Swiss National Science Foundation (Grant No 200020-121756), Fiberline Composites A/S, Denmark, supplier of the pultruded laminates, and Sika AG, Zurich, the adhesive supplier. References Brunner, A. J., B. R. K. Blackman, P. Davies, 2008. A status report on delamination resistance testing of polymer-matrix composites. Engineering Fracture Mechanics 75(9), 2779-2794. Davies, P., G. D. Sims, B. R. K. Blackman, A. J. Brunner, K. Kageyama, M. Hojo, K. Tanaka, G. Murri, C. Rousseau, B. Gieseke, R. H. Martin (1999. Comparison of test configurations for determination of mode II interlaminar fracture toughness results from international collaborative test programme. Plastics, Rubber, Composites Processing and Applications 28(9), 432-437. Reeder, J. R., J. H. Crews Jr, 1990. Mixed-mode bending method for delamination testing. AIAA Journal 28(7), 1270-1276. Williams, J. G., 1988. On the calculation of energy release rates for cracked laminates. International Journal of Fracture 36(2), 101-119. Hutchinson, J. W., Z. Suo, 1991. Mixed Mode Cracking in Layered Materials. Advances in Applied Mechanics. W. H. John and Y. W. Theodore, Elsevier. 29, 63-191. Rybicki, E. F., M. F. Kanninen, 1977. A finite element calculation of stress intensity factors by a modified crack closure integral. Engineering Fracture Mechanics 9(4), 931-938. Krueger, R., 2015. 1 - The virtual crack closure technique for modeling interlaminar failure and delamination in advanced composite materials A2 - Camanho, Pedro P. Numerical Modelling of Failure in Advanced Composite Materials. S. R. Hallett, Woodhead Publishing, 3-53. Mathews, M. J., S. R. Swanson, 2005. A numerical approach to separate the modes of fracture in interface crack propagation. Journal of Composite Materials 39(3), 247-264. Silva, A., M. J. M. De Freitas, 2003. Mixed-mode delamination growth of laminar composites by using three-dimensional finite element modeling. Fatigue and Fracture of Engineering Materials and Structures 26(6), 543-549. Agrawal, A., A. M. Karlsson, 2006. Obtaining mode mixity for a bimaterial interface crack using the virtual crack closure technique. International Journal of Fracture 141(1-2), 75-98. Raju, I. S., J. H. Crews Jr, M. A. Aminpour, 1988. Convergence of strain energy release rate components for Edge-Delaminated composite laminates. Engineering Fracture Mechanics 30(3), 383-396. Sorensen, L., J. Botsis, T. Gmür, L. Humbert, 2008. Bridging tractions in mode I delamination: Measurements and simulations. Composites Science and Technology 68(12), 2350-2358. Shahverdi, M., A. P. Vassilopoulos, T. Keller, 2013. Modeling effects of asymmetry and fiber bridging on Mode I fracture behavior of bonded pultruded composite joints. Engineering Fracture Mechanics 99, 335-348. Tamuzs, V., S. Tarasovs, U. Vilks, 2001. Progressive delamination and fiber bridging modeling in double cantilever beam composite specimens. Engineering Fracture Mechanics 68(5), 513-525. Sørensen, B. F., T. K. Jacobsen, 2009. Characterizing delamination of fibre composites by mixed mode cohesive laws. Composites Science and Technology 69(3-4), 445-456. Xu, X. P., A. Needleman, 1994. Numerical simulations of fast crack growth in brittle solids. Journal of the Mechanics and Physics of Solids 42(9), 1397-1434. De Morais, A. B., 2011. A new fibre bridging based analysis of the Double Cantilever Beam (DCB) test. Composites Part A: Applied Science and Manufacturing 42(10), 1361-1368.