PSI - Issue 60

A.M. Sreenath et al. / Procedia Structural Integrity 60 (2024) 256–263

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8 A. M. Sreenath and R. V. Prakash / Structural Integrity Procedia 00 (2024) 000–000 the repaired specimen [Cheng (2010)]. The similar trends are observed in this study also. Specimens repaired with double sided patch delivered comparatively higher failure loads than the single sided patch. Damage area filed with chopped fiber composites (i.e. higher stiffness material) exhibited higher load carrying capacity. This trend is noted in in almost all configurations studied in this paper. However, the percentage of improvement varies with configurations and this was documented in this paper. The current study only discussed with only one diameter of the damage removal and filling. Removing the complete asymmetry due to damage may be possible by removing a larger area and filling it with chopped fiber composites. However, that would defeat the aim of the study as the scarf repair methods are already available as a more sophisticated repair method. The patching at the bottom of the specimen gives a better performance. However, in the case of a practical application, this may not be a good solution. The rear side of an impact-damaged panel may not be easily accessible for repair. In such cases, filling the damaged region with chopped fiber composite and patching it on the top surface is comparable to patching at the rear without any damage treatment. This solution may be helpful, at least in some niche applications. 4. Conclusion The effect of treatment on the damaged area on the residual properties of the repaired specimens was studied. Removing the damaged material with epoxy or chopped fiber-filled composites improves the residual mechanical properties without any external patching. Filling the damaged region with epoxy does not increase the residual properties considerably compared with patching without any treatment. However, filling with chopped fiber composites improves repair efficiency significantly. The same trend is also continued in specimens repaired with external patching. In all the cases, the patching on both sides has the highest residual strength irrespective of the type of damage and the treatment at the damaged area. The patching on the bottom side of the panel gives better repair efficiency than at the top for the impact-damaged panels. The trends in repair efficiency were similar for the circular hole and the impact-damaged specimens. However, the relative advantages of each method were vastly different for the two cases. References Aabid A, Ibrahim YE, Hrairi M, Ali JSM., 2023, Optimization of Structural Damage Repair with Single and Double-Sided Composite Patches through the Finite Element Analysis and Taguchi Method. Materials (Basel), Cheng, X., Du, X., Zhang, J., Zhang J., Guo, X., Bao, J., 2018 ‘Effects of stacking sequence and rotation angle of patch on low-velocity impact performance of scarf repaired laminates’, Composites Part B: Engineering. Elsevier Ltd, 133, pp. 78–85 Cheng, P., X.J. Gong, D. Hearn, S. Aivazzadeh,2011 Tensile behaviour of patch-repaired CFRP laminates, Compos. Struct. 93 pp582–589. Dassault Systems., 2008, VUMAT for Fabric Reinforced Composites, Simulia Answers 3749, pp 1-10 Doung, C, Hui Wang, C, 2007, Composite Repair: Theory and Design. Elsevier Publications, The Netherlands Hua, X.F., Harisb A., Ridhab M.,Tan, V.B.C.,Tay T.E.,2018,‘Progressive failure of bolted single-lap joints of woven fibre-reinforced composites’, Composite Structures 189, pp. 443–454. Jefferson, A., Vellayaraj, A., Hom, N.D., 2018, Repair of Polymer Composites, Methodology, Techniques and Challenges, Woodhead publishing, United Kingdom Mohammadi, S., Yousefi, M., Khazaei, M.,2020, A review on composite patch repairs and the most important parameters affecting its efficiency and durability, Journal of Reinforced Plastics & Composites, pp 1-13 Shruthi, K., Saravanakumar, K., Arumugam, V., Suresh Kumar, C,, 2021, Effect of patch hybridisation on indentation resistance and residual performance of patch repaired glass/epoxy laminates using acoustic emission monitoring, Nondestructive testing and evaluation, 36(5), pp. 528-545 Sreenath, A.M., Prakash, R. V, 2021, Numerical Simulation of the Effect of Bonded Patch Repair on the Internal Stress Distribution, Proceedings of the ASME 2021 International Mechanical Engineering Congress and Exposition, Paper No: IMECE 2021-71302 Wan, Y., Takahashi, J.,2016, Tensile and compressive properties of chopped carbon fiber tapes reinforced thermoplastics with different fiber lengths and molding pressures, Composites Part-A ,87, pp 271–81 Wang, J., Callinan, R., 2014, Residual strengths of composite structures subjected to ballistic impact, Composite Structures, 117(1), pp. 423–32 Williamson, C., Daadbin, A, 1993, An investigation into using finite element analysis for epoxy resin joints, Materials and Design14(2), pp 91-95