PSI - Issue 53

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A. Neto et al. / Procedia Structural Integrity 53 (2024) 338–351 Alexandre de Oliveira Neto / Structural Integrity Procedia 00 (2019) 000–000

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Fig. 17. Top view of max principal strain layer analysis of L2

On the other hand, behaviour similarities between layers with the same orientation can be seen regarding the way the strain is distributed, and most notably the strain evolves in the opposite direction of the fibres, the 4th layer very apparent, as well as the outmost layer that is on the far right, orientation is 0 degrees axial, and it suffers transversely. In L2 the relation is apparent throughout unlike in L1, most likely due to the lower impact energy.

4. Conclusions In conclusion, starting with study points that require further attention, it was found that MAT 55 properties massively influenced the outcome of the results, not only affecting impact behaviour but failure criteria limit as well. So, it is critical to insert the correct values in the MAT card. Meshing posed a significant challenge, during which it was discovered that the selection and sizing of elements are pivotal for achieving a reliable and reasonably accurate simulation. However, the limitation imposed by layer thinness remained a persistent obstacle. Also, delamination was not a major consideration for this study, as it implied a lot more computational power and the software was not helpful when trying to achieve that. According to the main goals proposed for the present study, the most significant conclusions are: 1. Tube layup can drastically affect sustained energy absorption and damage, as Marcelo Leite Ribeiro et al. (2015); 2. L1 displayed less damage in comparable situations unlike Minak et al. (2009); 3. Invisible damage is still damage that may compromise part lifespan; 4. There is a relation between fibre orientation and strain distribution; 5. Maximum load and maximum displacement increase with the increasing of the impact energy; 6. Despite dissimilar impact energies, for each tier the permanent damage affected practically the same number of layers throughout; 7. There is a relation between elastic energy and the sustained damage; 8. For the tier of visible external damage, the tube is highly compromised because it suffered a lot internally to reach that point.

References Erhart, Tobias. 2011. “Review of Solid Element Formulations in LS-DYNA.” Dyna More.

https://www.dynamore.de/de/download/papers/forum11/entwicklerforum-2011/erhart.pdf. Hinton, M J, A S Kaddour, e and P D Soden. 2000. “Predicting failure in fibre composites: lessons learned from the world-wide failure exercise.”