PSI - Issue 33

A.F.M.V. Silva et al. / Procedia Structural Integrity 33 (2021) 138–148 Silva et al. / Structural Integrity Procedia 00 (2019) 000–000

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The L O effect is much similar to that of P m (Fig. 9 a), with a steady but non-proportional increase of with this parameter. This evolution is mainly caused by the associated P m increase, but also a minor improvement of the displacement at failure, which naturally increases the area. Over L O =10 mm, the relative improvements in U were 73.8% for L O =15 mm and 108.3% for L O =20 mm. Oppositely to this, there is not a clear relation in which regards to U - t SE (Fig. 9 b) and P m - t SE plots (Fig. 8 b), since here there is a clear reduction of U with higher t SE . Analysis of the P -  curves for all conditions showed that this behavior is related to the increase of joint stiffness for higher t SE , which then translates into smaller failure displacements and, consequently, lower areas under the P -  curves. On the other hand, for the tubular joint with t SE =1 mm, significant outer tube plasticization takes place, leading to a much higher failure displacement and U . Compared to the base geometry ( t SE =2 mm), reducing t SE to 1 mm improved U by 54.5%, which is significant, and increasing t SE led to a maximum U reduction of 20.3% for t SE =4 mm. Thus, although this geometrical parameter is not relevant in terms of P m , it highly affects U , and this should be considered in the design The impact CZM model implemented in this work was successfully validated with SLJ, which served as the basis for a purely numerical analysis on impact tubular adhesive joints. Actually, in the validation study, the P m difference was 15.8%, which is considered acceptable. The stress analysis showed asymmetric plots arising due to the different cross-sectional area of both tubes, and also typical oscillations deriving from the impact loading. A significant L O effect was found on both  xy and  y stresses, showing higher normalized peak stresses by increasing L O . On the other hand, t SE had a much smaller effect, which consisted of higher  xy and  y peak stresses for bigger t SE . As a result, P m increased with L O but at a non-proportional rate. The P m improvement between L O =10 and 20 mm was only 43.7%, which contrasts with the 100% area increase. t SE only marginally affected P m . The U evolution followed the same trend for L O (maximum increase of 108.3% between limit L O ), but it highly diminished with t SE (up to 20.3% for t SE =4 mm compared to t SE =2 mm). The difference is related to the  influence on U , which does not occur for P m . As a final result of this work, a working model and design guidelines were proposed for impact strength prediction of tubular adhesive joints. References of these joints. 4. Conclusions Adams, R. D. and Peppiatt, N. A., 1977. Stress Analysis of Adhesive Bonded Tubular Lap Joints. The Journal of Adhesion 9(1), 1-18. Barbosa, D. R., Campilho, R., Rocha, R. J. B. and Ferreira, L. R. F., 2018. 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