PSI - Issue 8

Amir Ghorbani / Procedia Structural Integrity 8 (2018) 552–560

559

A. Ghorbani / Structural Integrity Procedia 00 (2017) 000 – 000

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failure load decreases by the scarf angle increases. Different SIF values were calculated in the close neighborhood of singular zone also. With respect to the fracture mechanics for the brittle failure, it can be concluded that the recorded failures are not a pure brittle interface failure and other failure types occur and presence in the specimen. However, the shear stress is quite well overlapped (Fig. 6.). It means this parameter could be the driving force for the joint’s failure. In order to analyze the possible failure criteria for ScJ, maximum principal stress and Von mises equivalent stress were considered based on FE results to compare with interface shear stress. The FE shear stress value for different scarf angle and adherend thickness for Li et al. (2015) represent a small scatter, while a larger scatter can be seen for Von mises and principal stress curves. An approval comparing on Kumar et al. FE results, also demonstrates that the shear stress can be employed as a reliable failure criterion for ScJ with brittle failure in the interface. In this study, after a literature survey on the experimental and numerical studies, compiled results were analyzed in failure mechanism point of view. The failure of the bondline region was categorized into two main types of ductile and brittle. The average shear stress which is introduced an accurate criterion for ductile adhesives was employed to understanding the influence of the overlap length on the single-lap composite bo nded joint’s failure. In consequence, considerably small to be neglected amounts were calculated for the shear stress in the different overlap length. Afterwards, a two-dimensional numerical analysis by employing Finite Element Method (FEM) and a developed analytical solution were implemented to realize the correlation of the results and understanding the failure behavior of the brittle adhesive bonded joints. scarf-lap joints with interface failure was considered. Despite the fact of the different amount for K-factor, a satisfactory agreement was concluded in comparing the results. Finally, a discussion on the possible failure criteria for brittle failure in the bi-material corner of ScJs was performed. The best results were found for the interface shear stress with a well overlapping for various scarf angles. References ASTM D5573, 2011. Standard Practice for Classifying Failure Modes in Fiber-Reinforced-Plastic ( FRP ). ASTM International 15, 3 – 5. Campilho, R. D. S. G., Banea, M. D., Neto, J. A. B. P., Da Silva, L. F. M., 2013. Modelling adhesive joints with cohesive zone models: Effect of the cohesive law shape of the adhesive layer. International Journal of Adhesion and Adhesives 44, 48 – 56. Castagnetti, D., Spaggiari, A., Dragoni, E., 2011. Effect of Bondline Thickness on the Static Strength of Structural Adhesives Under Nearly-Homogeneous Shear Stresses. The Journal of Adhesion 87, 780 – 803. da Silva, L. F. M., das Neves, P. J. C., Adams, R. D., Spelt, J. K., 2009. Analytical models of adhesively bonded joints-Part I: Literature survey. International Journal of Adhesion and Adhesives 29, 319 – 330. da Silva, L. F. M., das Neves, P. J. C., Adams, R. D., Wang, A., Spelt, J. K., 2009. Analytical models of adhesively bonded joints-Part II: Comparative study. International Journal of Adhesion and Adhesives 29, 331 – 341. Gent, A. N., 1974. Fracture mechanics of adhesive bonds. Rubber Chemistry and Technology 47, 202-212. Gleich, D. M., Van Tooren, M. J. L., Beukers, A., 2001. Analysis and evaluation of bondline thickness effects on failure load in adhesively bonded structures. Journal of Adhesion Science and Technology 15, 1091 – 1101. Harris, J. A., Adams, R. A., 1984. Strength prediction of bonded single lap joints by non-linear finite element methods. International Journal of Adhesion and Adhesives 4, 65 – 78. Ji, G., Ouyang, Z., Li, G., 2013. Effects of bondline thickness on Mode-I nonlinear interfacial fracture of laminated composites: An experimental study. Composite Part B: Engineering 47, 1 – 7. Kumar, S. B., Sridhar, I., Sivashanker, S., Osiyemi, S. O., Bag, A., 2006. Tensile failure of adhesively bonded CFRP composite scarf joints. Materials Science and Engineering: B 132, 113 – 120. Li, J., Yan, Y., Zhang, T., Liang, Z., 2015. Experimental study of adhesively bonded CFRP joints subjected to tensile loads. International Journal of Adhesion and Adhesives 57, 95 – 104. Neto, J. A. B. P., Campilho, R. D. S. G., Da Silva, L. F. M., 2012. Parametric study of adhesive joints with composites. International Journal of Adhesion and Adhesives 37, 96 – 101. 5. Conclusion