PSI - Issue 33

R.F.N. Brito et al. / Procedia Structural Integrity 33 (2021) 665–672 Brito et al. / Structural Integrity Procedia 00 (2019) 000–000

671

7

b)

a)

Figure 4. Normalized stress distributions along the adhesive layer's mid-thickness: a) peel stress, b) shear stress.

4. Conclusions This work aimed to investigate the influence of the overlap length ( L O ) on joint strength ( P m ) and on the stress distributions of stepped-lap joints bonded with a ductile adhesive through an experimental and numerical study. For the composite joints bonded, P m increased linearly with L O . The geometry of the stepped-lap joint allows reducing the stresses along L O , compared to a single-lap joint (SLJ). However, there still are stress concentrations at the edges of each step, which could initiate damage. Furthermore, these stress concentrations would cause delamination of the composite substrates. Although composite substrates due to their high stiffness provide a good load transfer through the joint in relation to aluminum substrates, for long L O it is important to reduce stress concentrations to avoid delamination of the substrates. References Abdel Wahab, M.M., 2015. Simulating mode I fatigue crack propagation in adhesively-bonded composite joints. Fatigue Fract. Adhes. Compos. Joints 323–344. https://doi.org/10.1016/B978-0-85709-806-1.00011-2 Adams, R.D., Peppiatt, N.A., 1974. Stress analysis of adhesive-bonded lap joints. J. Strain Anal. 9, 185–196. https://doi.org/10.1243/03093247V093185 Alfano, G., 2006. On the influence of the shape of the interface law on the application of cohesive-zone models. Compos. Sci. Technol. 66, 723– 730. https://doi.org/10.1016/J.COMPSCITECH.2004.12.024 Campilho, R.D.S.G., 2017. Cohesive Zone Modelling for Static Applications, in: Campilho, R.D.S.G. (Ed.), Strength Prediction of Adhesively Bonded Joints. CRC Press, pp. 122–160. 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. Int. J. Adhes. Adhes. 44, 48–56. https://doi.org/10.1016/J.IJADHADH.2013.02.006 Chowdhury, N.M., Chiu, W.K., Wang, J., Chang, P., 2016. Experimental and finite element studies of bolted, bonded and hybrid step lap joints of thick carbon fibre/epoxy panels used in aircraft structures. Compos. Part B Eng. 100, 68–77. https://doi.org/10.1016/j.compositesb.2016.06.061 Crocombe, A.D., 2005. Stress Analysis, in: Adams, R.D. (Ed.), Adhesive Bonding. Science, Technology and Applications. Woodhead Publishing Limited, Cambridge, England. 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. Int. J. Adhes. Adhes. 29, 319–330. https://doi.org/10.1016/j.ijadhadh.2008.06.005 da Silva, L.F.M., Giannis, S., Adams, R D, Nicoli, E., Cognard, J.-Y., Créac’hcadec, R., Blackman, B.R.K., Singh, H.K., Frazier, C.E., Sohier, L.,