IWPDF2023

Study of different initiation and propagation criteria in the XFEM modelling of scarf adhesive joints G.J.C. Pinheiro 1 , ∗ , I.R.S. Araújo 1 , R.D.S.G Campilho 1 , 2 , J.P.A Valente 1 ,M.J.R. Queirós 1 , K. Madani 3 1 Department of Mechanical Engineering, ISEP – School of Engineering, Polytechnic Institute of Porto, R. Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal. 2 Institute of Science and Innovation in Mechanical and Industrial Engineering (branch Faculty of Engineering of University of Porto), Rua Dr. Roberto Frias, 400, 4200-465 Porto, Portugal. 3 Department of Mechanical Engineering, University of Sidi Bel Abbes, BP 89 Cité Ben M’hidi, Sidi Bel Abbes 22000, Algeria

∗ 1130440@isep.ipp.pt

Keywords: Adhesive joint, Structural adhesives, Scarf joint, Cohesive zone models, eXtended finite element method.

There are numerous applications for adhesive bonds, which are used in various industry sectors, from aerospace to footwear. In the aerospace and aeronautics sector, its use is extremely im portant, as it is possible to obtain strong and light connections, capable of resisting corrosion. There are several factors that affect the behavior of an adhesive joint. Thus, there is a need to assess the impact of these main factors on the bond strength, such as the type of adhesive (brittle, ductile or transition of both) and the overlap length ( L 0 ). On the other hand, scarf joints find application in high-responsibility structures, including composite structures, due to their high efficiency. In this case, one of the most relevant geometric parameters is the scarf angle ( α ). The main objective of this work is to carry out a study to estimate the mechanical behavior of scarf adhesive joints as a function of α and the type of adhesive. Thus, an experimental and numerical study of scarf joints was carried out using the Extended Finite Element Method (XFEM), in which different adhesives such as the Araldite ® AV138, the Araldite ® 2015 and the SikaForce ® 7888 were applied. Aluminum (AW6082-T651) adherends were used in joints with different α , being subjected to a tensile load, in order to evaluate their performance and validate the applicability of the XFEM for the purposes of strength prediction. Therefore, the values obtained experimentally and numerically were compared for each of the adhesives and α to validate the XFEM numerical method for determining the mechanical behavior of adhesive joints. The results obtained in the scope of this work allowed to clearly validate that the XFEM numerical method returns results very close to those obtained experimentally. References [1] Wan, V.V.C., MacLachlan, D.W., Dunne, F.P.E. (2014). A stored energy criterion for fatigue crack nucleation in polycrystals. International Journal of Fatigue, 68, 90–102. [2] Zheng, Z., Zhao, P., Zhan, M., Li, H., Lei, Y., Fu, M.W. (2022). Understanding of the fatigue crack nucleation in metallic sealing rings by explicitly incorporating the deformation history from manufacturing to service. International Journal of Fatigue, 164, 107174.

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