PSI - Issue 52

Valerio Acanfora et al. / Procedia Structural Integrity 52 (2024) 340–347 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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4. Conclusions In this paper a numerical methodology that is capable of simulating a low velocity impact event on composite structures has been presented. The results indicate that an appropriate discretization level must be used through the thickness in order to accurately account for the bending stiffness of the plate. Additionally, a high number of elements through the thickness is necessary for the evaluation of the delamination onset and its subsequent evolution. The final experimental-numerical correlation demonstrates that the numerical models with cohesive parameters provide the closest results to the experimental ones, in terms of the impact force history and impactor displacement (Figure 11). Both cohesive analyses demonstrated an excellent experimental correlation, although the model with eight elements through the thickness resulted in an overestimation of the maximum contact force when compared to the experimental curve, which caused a noticeable increase in the displacement curve and the duration of the contact. Consequently, the model with four elements through the thickness not only offers the best balance between computational cost and execution time, but it is also the numerical model closest to the experimental results. A slight discrepancy is observable in the contact duration, due to the fact that gravity effects were not considered.

Figure 11: Comparison between the less accurate model (one element through thickness with no damage) and the most accurate one (four elements though thickness with both intra-laminar and inter-laminar damage) . References [1] Yang, G., Park, M., Park, S.-J., 2019. Recent progresses of fabrication and characterization of fibers-reinforced composites: A review. Composites Communications 14, 34 – 42. DOI: 10.1016/j.coco.2019.05.004. [2] Zaid, N.Z.M., Rejab, M.R.M., Mohamed, N.A.N., 2016. Sandwich Structure Based on Corrugated-Core: A Review. MATEC Web of Conferences 74, art. no. 00029. DOI: 10.1051/matecconf/20167400029 [3] Riccio, A., Di Costanzo, C., Di Gennaro, P., Sellitto, A., Raimondo A.,2017. Intra-laminar progressive failure analysis of composite laminates with a large notch damage. Engineering Failure Analysis 73, 97 – 112. DOI: 10.1016/j.engfailanal.2016.12.012. [4] Dicker, M.P.M., Duckworth, P.F., Baker, A.B., Francois, G., Hazzard, M.K., Weaver, P.M., 2014. Green composites: A review of material attributes and complementary applications. Composites Part A: Applied Science and Manufacturing 56, 280 – 289. DOI: 10.1016/j.compositesa.2013.10.014. [5] Polimeno, U., Meo, M., 2009. Detecting barely visible impact damage detection on aircraft composites structures. Composite Structures 91(4), 398 – 402. DOI: 10.1016/j.compstruct.2009.04.014. [6] Talreja, R., Phan, N., 2019. Assessment of damage tolerance approaches for composite aircraft with focus on barely visible impact damage. Composite Structures 219, 1 – 7. DOI: 10.1016/j.compstruct.2019.03.052. [7] Sun, X.C., Hallett, S.R., 2017. Barely visible impact damage in scaled composite laminates: Experiments and numerical simulations. International Journal of Impact Engineering 109, 178 – 195. DOI: 10.1016/j.ijimpeng.2017.06.008. [8] Russo, A., Zarrelli, M., Sellitto, A., Riccio, A., 2019. Fiber bridging induced toughening effects on the delamination behavior of composite stiffened panels under bending loading: A numerical/experimental study. Materials 12(15), art. no. 2407. DOI: 10.3390/ma12152407. [9] Acanfora, V., Zarrelli, M., Riccio, A., 2023. Experimental and numerical assessment of the impact behaviour of a composite sandwich panel with a polymeric honeycomb core. International Journal of Impact Engineering 171, art. no. 104392. DOI: 10.1016/j.ijimpeng.2022.104392. [10] Liu, D., 1988. Impact-Induced Delamination — A View of Bending Stiffness Mismatching. Journal of Composite Materials 22(7), 674 – 692.