PSI - Issue 83

R.J.B. Rocha et al. / Procedia Structural Integrity 83 (2026) 187–195

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c)

Fig. 7. Average experimental maximum load P max as a function of L O for SJ using (a) PLA, (b) ABS and (c) PETG adherends bonded with 2015 and 7752.

Direct comparison of Fig. 6 and Fig. 7 highlights the key geometric effect: conventional SLJ benefits substantially from longer L O thanks to increased shear area, while SJ suffer from local peel stress concentrations that limit strength gains beyond L O =5 mm. Nevertheless, the PLA/2015 pairing is optimal in both geometries, demonstrating robustness independent of joint configuration. The CZM predictions agree with the experimental P max values within <9 % error for both joint types, confirming the reliability of the numerical approach. 4. Conclusions This work presented a comparative experimental and numerical study on the tensile behavior of SLJ and SJ manufactured with AM thermoplastic adherends. The results showed that the PLA adherend bonded with 2015 consistently delivered the highest P max and stiffness in both geometries. While SLJ exhibited a clear strength increase with L O , due to the increase of the shear area, SJ reached an earlier strength plateau due to adherend failure triggered at the step transition. Failure modes ranged from predominantly cohesive in the adhesive layer, more frequent with the ductile 7752, to adherend-dominated, dominant with the stiff 2015 at larger L O . The more flexible adhesive demonstrated higher failure  , especially in combination with ABS or PETG adherends. The CZM approach presented a very accurate and reliable method to predict joint failure for both joint configurations under investigation. The results were very close to what was found in experiments with low errors. These findings confirm that conventional SLJ are more efficient to maximize load-carrying capacity in AM thermoplastic assemblies, yet SJ constitute a practical alternative when design constraints require geometric transitions or improved alignment. Future research should address fatigue performance, other joint configuration geometries and advanced surface treatments to further optimize adhesive AM joints. References Ahmad, M. N., Yahya, A., 2023. Effects of 3D Printing Parameters on Mechanical Properties of ABS Samples. Designs 7(6): 136. Atahan, M. G., Apalak, M. K., 2022. Loading-rate effect on tensile and bending strength of 3D-printed polylactic acid adhesively bonded joints. Journal of Adhesion Science and Technology 36(3): 317-344. Attaran, M., 2017. The rise of 3-D printing: The advantages of additive manufacturing over traditional manufacturing. Business Horizons 60(5): 677-688. Campilho, R. D. S. G., Banea, M. D., Neto, J. A. B. P., 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 & Adhesives 44: 48–56. Faneco, T. M. S., Campilho, R. D. S. G., Silva, F. J. G., Lopes, R. M., 2017. Strength and fracture characterization of a novel polyurethane adhesive for the automotive industry. Journal of Testing and Evaluation 45(2): 398-407. Khosravani, M. R., Soltani, P., Weinberg, K., Reinicke, T., 2021. Structural integrity of adhesively bonded 3D-printed joints. Polymer Testing 100: 107262. Klahn, C., Singer, D., Meboldt, M., 2016. Design Guidelines for Additive Manufactured Snap-Fit Joints. Procedia CIRP 50: 264-269. König, N., Schockenhoff, F., König, A., Diermeyer, F., 2022. Method for Segmentation and Hybrid Joining of Additive Manufactured Segments in Prototyping Using the Example of Trim Parts. Designs 6(1): 2. Manoj, I., Kumar Shah, A., Jain, A., 2024. Strength and failure assessments of 3D printed PLA single lap joints: Experimental and numerical analysis. Engineering Failure Analysis 161: 108257. Öztürk, F. H., Marques, E. A. S., Carbas, R. J. C., da Silva, L. F. M., 2024. Experimental and numerical study on mechanical behavior of 3D printed