PSI - Issue 60

Rakesh Bhadra et al. / Procedia Structural Integrity 60 (2024) 149–164 Bhadra et al. / Structural Integrity Procedia 00 (2023) 000 – 000

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studies in the literature and found to be in good agreement. The parameters that were varied in the analysis were the wall thickness of the CNTs and the inhomogeneity parameter. This was done to understand how the contact behavior of the nanocomposite changes with these parameters. The results of the analysis were presented in terms of contact force, contact area, contact pressure distribution, and nodal displacements. Stress distribution and stress state contour plots were also generated. The results of this study could be used to benchmark future studies in this area. The analysis of results from the model leads to the following observation:  The contact force exhibits an increase with the thickness of CNTs for a specific indentation depth, and conversely, it decreases as the thickness of CNTs decreases, potentially falling below the contact force observed for the matrix material alone. Similarly, the contact force demonstrates an increase with higher elastic gradation parameters.  The contact area increases with increasing the wall thickness of CNTs and with increasing elastic gradation parameters. This is because the larger contact area is required to accommodate the larger contact force.  The von Mises stress is influenced by changes in gradation parameters. It is evident that an increase in the gradation parameter leads to a rise in value the stress distribution. An important finding is that the peak stress occurs in the vicinity of the contact zone with the CNTs. This can be attributed to the higher yield strength of the CNTs compared to the matrix material.  The yielding behavior of a CNT-FGM nanocomposite is affected by the elastic gradation parameter. A higher elastic gradation parameter corresponds to a more graded matrix, which is stiffer and can deform less under the indenter contact effect.  Analysis of the nodal displacement in the y-direction through plotted data reveals the occurrence of pile up behavior in the nanocomposite reinforced with CNTs of lower thickness at the end of the unloading stage.  The results indicate that the contact parameter improves with an increase in the gradation parameter for the matrix material. Similarly, the contact behavior improves with an increase in the thickness of the CNTs in the nanocomposite. References Ahmed, K. S., Ibrahim, I., & Keng, A. K., 2020. “Advanced Nano indentation Simulations for Carbon Nanotube Reinforced Nanocomposites”. Heliyon, 6(8). Bhadra, R., Jana, T., Mitra, A., & Sahoo, P., 2022. “Flattening Cylindrical Contact Analysis of Single Walled Carbon Nanotube (SWCNT) Nanocomposite”. International Journal of Surface Engineering and Interdisciplinary Materials Science (IJSEIMS ) , 10 (1), 1-22. Bhadra, R., Jana, T., Mitra, A., & Sahoo, P., 2023. Finite element based indentation contact analysis of SWCNT nano-composite. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science , 09544062231169138. Bhadra, R., Jana, T., Mitra, A., & Sahoo, P., 2023a. “Effect of CNT radius on flattening contact behaviour of CNT -Al nanocomposite: A numerical approch”. Reports in Mechanical Engineering , 4 (1), 121-130. Brizmer, V., Kligerman, Y., & Etsion, I., 2006. “The Effect of Contact Conditions and Material Properties on the Elasticity T erminus of A Spherical Contact”. International journal of solids and structures, 43(18-19), 5736-5749. Dorozhkin, S. V. 2011. “Biocomposites and hybrid biomaterials based on calcium orthophosphates”. Biomatter , 1 (1), 3-56 Ghatage, P. S., Kar, V. R., & Sudhagar, P. E., 2020. “On the Numerical Modelling and Analysis of Multi -Directional Functionally Graded Composite Structures: A Review. Composite Structures”, 236, 111837. Giannakopoulos, A. E., & Suresh, S., 1997. “Indentation of Solids with Gradients in Elastic Properties: Part I. Point Force”. International Journal of Solids and Structures, 34(19), 2357-2392. Hallad, S. A., Banapurmath, N. R., Patil, A. Y., Hunashyal, A. M., & Shettar, A. S., 2016. “Studies on the Effect of Multi -Walled Carbon Nanotube – Reinforced Polymer-Based Nano- Composites Using Finite Element Analysis Software Tool”. Proceedings of the Institution of Mechanical Engineers, Part N: Journal of Nanomaterials, Nanoengineering and Nanosystems, 230(4), 200-212.