Title: Enhancement of the Open Hole Tension Properties of the Nanocomposites Using Carbon Nano-Coils

Authors: Colin A. Bentley, Luke Anthony Granillo, and Ramanan Sritharan

DOI: 10.33599/nasampe/c.25.39

Abstract: Laminated composite materials offer high specific strength and specific stiffness for low weight, making them widely used in fields like the aerospace, energy, and automotive industries. Holes are a crucial design feature in assembling multiple composite parts, which is a common practice in various structures. The holes act as stress concentrators, creating the need to understand the effects of holes on composites to design safe parts. The addition of nanomaterials to an epoxy matrix has been shown to increase the strength of polymer composites. Previous research, most of which has focused on straight carbon nanotubes (CNTs) and other nanomaterials, found improvements in the open-hole tensile strength of composite laminates through the addition of these materials in the polymer matrix. Helical carbon nanotubes (HCNTs) have been found to have some advantage over straight CNTs (SCNTs) due to their three-dimensional heli coil shape that provides stronger interlocking within the matrix. The goal of this research is to investigate the effects of CNTs on the open-hole tension (OHT) properties of polymer nanocomposites by comparing pristine SCNTs, pristine HCNTs, and functionalized straight CNTs. In this research, two different weight percentages (i.e., 0.025wt% and 0.05wt%) of three different CNTs were added to epoxy resin to fabricate test specimens. These specimens were then cut in to coupons, holes were drilled at their center, and an open-hole tension test was performed per the ASTM standard D5766/D5766M – 23. The test results from this pilot study showed improvements in the tensile strength, tensile modulus, and strain at failure of polymer nanocomposites reinforced with CNTs when compared to the results of neat epoxy samples.

References: [1] A. R. Ghasemi, M. M. Mohammadi, and M. Mohandes, “The role of carbon nanofibers on thermo-mechanical properties of polymer matrix composites and their effect on reduction of residual stresses,” Composites Part B: Engineering, vol. 77, pp. 519–527, Aug. 2015, doi: 10.1016/j.compositesb.2015.03.065. [2] K. Lau, C. Gu, and D. Hui, “A critical review on nanotube and nanotube/nanoclay related polymer composite materials,” Composites Part B: Engineering, vol. 37, no. 6, pp. 425–436, Jan. 2006, doi: 10.1016/j.compositesb.2006.02.020. [3] J. B. Knoll, B. T. Riecken, N. Kosmann, S. Chandrasekaran, K. Schulte, and B. Fiedler, “The effect of carbon nanoparticles on the fatigue performance of carbon fibre reinforced epoxy,” Composites Part A: Applied Science and Manufacturing, vol. 67, pp. 233–240, Dec. 2014, doi: 10.1016/j.compositesa.2014.08.022. [4] T. Y. Chou, H.-Y. Tsai, and M. C. Yip, “Preparation of CFRP with modified MWCNT to improve the mechanical properties and torsional fatigue of epoxy/polybenzoxazine copolymer,” Composites Part A: Applied Science and Manufacturing, vol. 118, pp. 30–40, Mar. 2019, doi: 10.1016/j.compositesa.2018.11.026. [5] L. Toubal, M. Karama, and B. Lorrain, “Stress concentration in a circular hole in composite plate,” Composite Structures, vol. 68, no. 1, pp. 31–36, Apr. 2005, doi: 10.1016/j.compstruct.2004.02.016. [6] X. Li, Z. Guan, Z. Li, and L. Liu, “A new stress-based multi-scale failure criterion of composites and its validation in open hole tension tests,” Chinese Journal of Aeronautics, vol. 27, no. 6, pp. 1430–1441, Dec. 2014, doi: 10.1016/j.cja.2014.10.009. [7] F. M. Monticeli, F. R. Fuga, M. A. Arbelo, and M. V. Donadon, “The effect of fibre orientation on fatigue crack propagation in CFRP: Finite fracture mechanics modelling for open-hole configuration,” Engineering Failure Analysis, vol. 161, p. 108278, Jul. 2024, doi: 10.1016/j.engfailanal.2024.108278. [8] J. R. Pothnis, D. Kalyanasundaram, and S. Gururaja, “Enhancement of open hole tensile strength via alignment of carbon nanotubes infused in glass fiber - epoxy - CNT multi-scale composites,” Composites Part A: Applied Science and Manufacturing, vol. 140, p. 106155, Jan. 2021, doi: 10.1016/j.compositesa.2020.106155. [9] K. Han, W. Zhou, R. Qin, G. Wang, and L.-H. Ma, “Effects of carbon nanotubes on openhole carbon fiber reinforced polymer composites,” Materials Today Communications, vol. 24, p. 101106, Sep. 2020, doi: 10.1016/j.mtcomm.2020.101106. [10] J. R. Pothnis, A. K. Hajagolkar, A. R. Anilchandra, R. Das, and S. Gururaja, “Open-hole fatigue testing of UD-GFRP composite laminates containing aligned CNTs using infrared thermography,” Composite Structures, vol. 324, p. 117557, Nov. 2023, doi: 10.1016/j.compstruct.2023.117557. [11] M. Tarfaoui, K. Lafdi, and A. El Moumen, “Mechanical properties of carbon nanotubes based polymer composites,” Composites Part B: Engineering, vol. 103, pp. 113–121, Oct. 2016, doi: 10.1016/j.compositesb.2016.08.016. [12] J. Körbelin, B. Kötter, H. Voormann, L. Brandenburg, S. Selz, and B. Fiedler, “Damage tolerance of few-layer graphene modified CFRP: From thin-to thick-ply laminates,” Composites Science and Technology, vol. 209, p. 108765, Jun. 2021, doi: 10.1016/j.compscitech.2021.108765. [13] S. Prakash, M. Prathab, M. Dhanashekar, and V. S. S. Kumar, “Open Hole Tensile Behaviour of Nano Fillers (SiC & Banana) in CNSL/Epoxy Resin Reinforeced with Basalt fiber,” Materials Today: Proceedings, vol. 5, no. 2, Part 2, pp. 8631–8637, Jan. 2018, doi: 10.1016/j.matpr.2017.11.562. [14] X.-F. Li, K.-T. Lau, and Y.-S. Yin, “Mechanical properties of epoxy-based composites using coiled carbon nanotubes,” Composites Science and Technology, vol. 68, no. 14, pp. 28762881, Nov. 2008, doi: 10.1016/j.compscitech.2007.10.019. [15] K. Lau, M. Lu, and K. Liao, “Improved mechanical properties of coiled carbon nanotubes reinforced epoxy nanocomposites,” Composites Part A: Applied Science and Manufacturing, vol. 37, no. 10, pp. 1837–1840, Oct. 2006, doi: 10.1016/j.compositesa.2005.09.019. [16] N. Kadhim et al., “Remarkable Improvement in the Mechanical Properties of Epoxy Composites Achieved by a Small Amount of Modified Helical Carbon Nanotubes,” Polymers, vol. 10, no. 10, Art. no. 10, Oct. 2018, doi: 10.3390/polym10101103. [17] A. Ali, A. Andriyana, S. B. A. Hassan, and B. C. Ang, “Fabrication and Thermo-Electro and Mechanical Properties Evaluation of Helical Multiwall Carbon Nanotube-Carbon Fiber/Epoxy Composite Laminates,” Polymers, vol. 13, no. 9, Art. no. 9, Jan. 2021, doi: 10.3390/polym13091437. [18] R. Sritharan and D. Askari, “Enhancing the short-beam strength of composite laminates using helical carbon nanotubes,” Composites Part B: Engineering, vol. 221, p. 108999, Sep. 2021, doi: 10.1016/j.compositesb.2021.108999. [19] R. Sritharan and D. Askari, “Improvement of the tensile properties of laminated composites reinforced with Heli-Coil forms of carbon nanotubes,” Polymer Composites, vol. 44, no. 10, pp. 7070–7083, 2023, doi: 10.1002/pc.27619. [20] R. Sritharan, S. R. Taklimi, A. Ghazinezami, and D. Askari, “The chemical functionalization advantages of carbon nano heli-coil reinforcements for multifunctional polymeric nanocomposites,” Journal of Composite Materials, vol. 59, no. 14, pp. 1705–1720, Jun. 2025, doi: 10.1177/00219983251316333. [21] R. Sritharan and D. Askari, “Effects of Helical Carbon Nanotubes on Mechanical Performance of Laminated Composites and Bonded Joints,” SAE Int. J. Adv. & Curr. Prac. in Mobility, vol. 2, no. 3, Art. no. 2020-01–0029, Mar. 2020, doi: 10.4271/2020-01-0029. [22] R. Sritharan and D. Askari, “Enhancement of the Mechanical Properties And Bonding of Composite Laminates and Assemblies Using Carbon Nano-Coils,” presented at the CAMX 2022, NA SAMPE, Oct. 2022. doi: 10.33599/nasampe/c.22.0137. [23] R. Sritharan, D. Askari, R. Sritharan, and D. Askari, “Interlaminar Properties Improvement of Nanocomposites Using Coiled Nanomaterials,” presented at the AeroTech® Digital Summit, SAE International, Mar. 2021. doi: 10.4271/2021-01-0027. [24] R. Sritharan, S. R. Taklimi, A. Ghazinezami, and D. Askari, “Mechanical properties improvement of polymeric nanocomposites reinforced with chemically treated helical carbon nanotubes: influence of sonication time and molarities of nitric-sulfuric-hydrochloric acids,” presented at the CAMX 2018, NA SAMPE, 2018, pp. 1–14. [25] R. Sritharan, S. Taklimi, A. Ghazinezami, and D. Askari, “Chemically Treated Helical Carbon Nanotubes Reinforcement for Polymeric Nanocomposites: Influence of Sonication Time and Treatment Sequence with a Mixture of Nitric-Sulfuric-Hydrochloric Acids at High Molarities,” in CAMX 2024, NA SAMPE, 2024. doi: 10.33599/nasampe/c.24.0302. [26] Standard Test Method for Open-Hole Tensile Strength of Polymer Matrix Composite Laminates, D5766/D5766M. doi: 10.1520/D5766_D5766M-23. [27] R. Sritharan and D. Askari, “A design of experiment study to investigate the effects of hardener concentration, stirring time, and air bubbles on the tensile strength of epoxy resin,” Journal of Elastomers & Plastics, vol. 54, no. 7, pp. 1129–1147, Nov. 2022, doi: 10.1177/00952443221131197.

Conference: CAMX 2025

Publication Date: 2025/09/08

SKU: 39

Pages: 11

Price: $22.00