PSI - Issue 72

P.M.M. da Silva et al. / Procedia Structural Integrity 72 (2025) 69–76

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4. Conclusions The present work aimed at evaluating the mechanical and fracture behavior of SMC with different glass FVF. The materials were initially selected, and FVF between 15% and 45% were evaluated. The tensile mechanical tests showed a moderate increase of E with the fiber content (18.5% between limit FVF), and major improvements in  f (229.7%). The shear mechanical tests revealed moderate G improvements with FVF (28.5%) and nearly nil  f improvements (6.5%), since failure is matrix dominated. The tensile fracture tests showed a significant G IC improvement with FVF, over 400%, between limit FVF. Although the fibers are parallel to the crack growth, fiber bridging led to this reported strengthening process. The shear fracture tests revealed G IIC improvements of 72.9% which, although smaller than G IC , is still significant. Thus, in view of the obtained results, it can be concluded that FVF are clearly recommended for structural applications, due to significantly higher properties, except for shear properties (  f and G IIC ) in which, despite the moderate differences due to fiber bridging phenomena, may not justify the increase in FVF. References Adams, D. F., 2010. Block shear strength of adhesive bonds. CompositesWorld. Assmuth, V., Meschut, G., 2022. Effect of low-profile additives on the durability of adhesively bonded sheet moulding compound (SMC). International Journal of Adhesion and Adhesives 112: 103036 Azevedo, J. C. S., Campilho, R. D. S. G., da Silva, J. F. G., Faneco, T. M. S., Lopes, R. M., 2015. Cohesive law estimation of adhesive joints in mode II condition. Theoretical and Applied Fracture Mechanics 80: 143-154 Campilho, R. D. S. G., Moura, D. C., Banea, M. D., da Silva, L. F. M., 2014. Adherend thickness effect on the tensile fracture toughness of a structural adhesive using an optical data acquisition method. International Journal of Adhesion and Adhesives 53: 15-22. Constante, C. J., Campilho, R. D. S. G., Moura, D. C., 2015. Tensile fracture characterization of adhesive joints by standard and optical techniques. Engineering Fracture Mechanics 136: 292-304 Davies, P., Casari, P., Carlsson, L. A., 2005. Influence of fibre volume fraction on mode II interlaminar fracture toughness of glass/epoxy using the 4ENF specimen. Composites Science and Technology 65(2): 295-300 de Moura, M. F. S. F., Campilho, R. D. S. G., Gonçalves, J. P. M., 2009. Pure mode II fracture characterization of composite bonded joints. International Journal of Solids and Structures 46(6): 1589-1595 Figueiredo, J. C. P., Campilho, R. D. S. G., Marques, E. A. S., Machado, J. J. M., da Silva, L. F. M., 2018. Adhesive thickness influence on the shear fracture toughness measurements of adhesive joints. International Journal of Adhesion and Adhesives 83: 15-23 Gortner, F., Schüffler, A., Fischer-Schuch, J., Mitschang, P., 2022. Use of bio-based and renewable materials for sheet molding compounds (SMC) – Mechanical properties and susceptibility to fungal decay. Composites Part C: Open Access 7: 100242 Kandelbauer, A., Tondi, G., Zaske, O. C., Goodman, S. H. (2022). Unsaturated polyesters and vinyl esters. Handbook of thermoset plastics, Elsevier : 97-158 Masters, J. E., 1987. Correlation of Impact and Delamination Resistance in Interleafed Laminates. Proc. ICCM6/ECCM2 3: 96-107 Medina, J. A. H. (2014). Avaliação de Previsões de Fratura Elastoplástica, Tese de Doutoramento. PUC-Rio Monteiro, J. P. R., Campilho, R. D. S. G., Marques, E. A. S., da Silva, L. F. M., 2015. Experimental estimation of the mechanical and fracture properties of a new epoxy adhesive. Applied Adhesion Science 3(1): 25 Nony-Davadie, C., Peltier, L., Chemisky, Y., Surowiec, B., Meraghni, F., 2019. Mechanical characterization of anisotropy on a carbon fiber sheet molding compound composite under quasi-static and fatigue loading. Journal of Composite Materials 53(11): 1437-1457 Sørensen, B. F., Jacobsen, T. K., 1998. Large-scale bridging in composites: R-curves and bridging laws. Composites Part A: Applied Science and Manufacturing 29(11): 1443-1451 Trauth, A., Bondy, M., Weidenmann, K. A., Altenhof, W., 2018. Mechanical properties and damage evolution of a structural sheet molding compound based on a novel two step curing resin system. Materials & Design 143: 224-237 Vaidya, U., Penumadu, D., Theodore, M., 2022. Low-cost textile grade carbon fiber: Intermediates, Processes and Product Routes for Low-Cost Textile Grade Carbon Fiber Into Composites. SAMPE Journal 58(2) Xu, W., Ding, J., 2020. Correction of the large displacement effect on determination of mode I interlaminar fracture toughness of composite. Engineering Fracture Mechanics 238: 107279 Zuo, P., Vassilopoulos, A. P., 2021. Review of fatigue of bulk structural adhesives and thick adhesive joints. International Materials Reviews 66(5): 313-338