PSI - Issue 51

R.B.P. Barros et al. / Procedia Structural Integrity 51 (2023) 17–23 R.B.P. Barros et al. / Structural Integrity Procedia 00 (2022) 000–000

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2015 instead, the Kinloch methods’ points suggest a behavior between  =1 and 3/2, while the Grady’s points relate to  =3/2 or 2. The da Silva et al. points are not visible within the selected graphics’ limits. Previous works testing the SLB configuration led to  =0.5 (AV138) and  =0.5 or 1 (2015) (Santos and Campilho 2017).

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Fig. 5. Experimental fracture envelopes for the AV138 (a) and 2015 (b).

4. Conclusions The present work experimentally evaluated the CLS fracture test’s ability to predict G C and respective mode partitioning of adhesive joints. The P -  curves agreed well individually for each adhesive, and plasticization before failure was found for the 2015. Between the different data reduction methods, G T of the Brussat et al. method revealed an offset of 50%. Mode partitioning into G I and G II was accomplished by the possible methods, showing that the da Silva et al. method would predict an offset G I / G II ratio compared to the methods of Grady and Kinloch. These two methods predicted  =1 for the AV138. On the other hand, the 2015 results showed, for the Grady’s method, either  =3/2 or 2 and, for the Kinloch’s method, either  =1 or 3/2. As a final remark, the present work proposed fracture parameters to develop and implement bonded joints in structural applications, considering CZM for instance, which can improve and expedite the design process. References Azari, S., Eskandarian, M., Papini, M., Schroeder, J.A., Spelt, J. K., 2009. Fracture load predictions and measurements for highly toughened epoxy adhesive joints. Engineering Fracture Mechanics 76(13), 2039-2055. Brussat, T.R., Chiu, S.T., Mostovoy, S. (1977). Fracture mechanics for structural adhesive bonds. Glenwood Illinois 60425, Lockheed-California Company : 126. Campilho, R.D. (2017). Strength Prediction of Adhesively-bonded Joints, CRC Press. Campilho, R.D.S.G., Banea, M.D., Pinto, A.M.G., da Silva, L.F.M., de Jesus, A.M.P., 2011. Strength prediction of single- and double-lap joints by standard and extended finite element modelling. International Journal of Adhesion & Adhesives 31(5), 363-372. Constante, C.J., Campilho, R.D.S.G., Moura, D.C., 2015. Tensile fracture characterization of adhesive joints by standard and optical techniques. Engineering Fracture Mechanics 136, 292-304. da Silva, L.F.M., Esteves, V.H.C., Chaves, F.J.P., 2011. Fracture toughness of a structural adhesive under mixed mode loadings. Materialwissenschaft und Werkstofftechnik 42(5), 460-470. Datla, N., Papini, M., Schroeder, J., Spelt, J. J.K., 2010. Modified DCB and CLS specimens for mixed-mode fatigue testing of adhesively bonded thin sheets. International Journal of Adhesion & Adhesives 30(6), 439-447. Grady, J.E. (1992). Fracture toughness testing of polymer matrix composites, National Aeronautics and Space Administration, Office of Management. Gustafson, C.G., Hojo, M., Holm, D., 1989. A nonlinear analysis of the CLS specimen. Journal of Composite Materials 23(2), 146-162. Kinloch, A.J. (2012). Adhesion and adhesives: science and technology. Nova Iorque, EUA, Springer Science & Business Media. Leitão, A.C.C., Campilho, R.D.S.G., Moura, D.C., 2016. Shear Characterization of Adhesive Layers by Advanced Optical Techniques. Experimental Mechanics 56, 493-506. Park, S., Dillard, D.A., 2007. Development of a simple mixed-mode fracture test and the resulting fracture energy envelope for an adhesive bond. International Journal of Fracture 148(3), 261-271. Reeder, J.R., Crews, J. H., 1990. Mixed-mode bending method for delamination testing. AIAA Journal 28(7), 1270-1276. Ribeiro, T.E.A., Campilho, R.D.S.G., da Silva, L.F.M., Goglio, L., 2016. Damage analysis of composite–aluminium adhesively-bonded single-lap joints. Composite Structures 136, 25-33.