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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1. Introduction Functionally graded materials (FGMs) reinforced with carbon nanotubes (CNTs) are emerging as a promising class of advanced future materials. This is due to the fact that both FGMs and CNTs represent advanced materials in the realm of modern technological development. These composites offer a unique combination of properties, including high strength, stiffness, toughness, and excellent thermal and electrical conductivity. The design, fabrication, and characterization of FGMs reinforced by CNTs are complex and challenging tasks. Utilizing advanced manufacturing methods like chemical vapor deposition and powder metallurgy, CNT-FGM nanocomposites can be produce. These materials find extensive applications in areas traditionally dominated by FGMs. CNT-FGM outperforms FGM in miscellaneous applications, including aircraft and spacecraft components [Miyamoto and Kaysser, (1999)], biomedical devices like dental implants and prosthetics [Dorozhkin, (2011)], and extremely high temperature application [Pindera et al. (1995)] etc.. The versatility of CNT-FGM makes it a superior alternative to conventional FGM in various fields. The initial phase of this research involved the creation of a FEM numerical model for analyzing the spherical contact of elastoplastic material, as developed by Johnson (1987). This model was utilized to examine the contact behavior of elastoplastic materials under various loading conditions. Subsequently, Kral et al. (1993) extended this work by developing a FE model for indentation contact analysis, considering both loading and unloading conditions. The findings from these investigations underscored the significance of parameters such as contact pressure, contact force, and contact area in comprehending contact behavior, revealing the occurrence of secondary yielding during unloading. Concerning FGM, Jha et al. (2013) conducted a critical review of numerous studies from earlier literature, focusing on the vibration, buckling, stress, and stability issues of functionally graded (FG) plates. Despite considerable research in this domain, the review highlighted the ongoing need for further investigations to comprehensively understand the behavior of FG plates under various loading conditions. Sofiyev (2019) provided a review of buckling and vibration analyses, specifically for FGM and FG shells (conical, layered conical, and sandwich conical). The review under scored a predominant focus on conical shells and suggested the necessity for more research on the buckling and vibration of FG shells with alternative geometries.In a separate review, Sayyad and Ghugal (2017) covered the buckling, vibration, and bending analyses of sandwich beams and laminated composites. Ghatage et al. (2020) presented a comprehensive review of the modeling and investigation of multi directional functionally graded composite structures (FGCSs), noting a predominant emphasis on two-dimensional FGCSs. Zhao et al. (2020) focused on studies related to FGCSs reinforced with graphene and graphene platelets (GPLs). Yengejeh et al. (2017) conducted a comprehensive study on static, vibration, and buckling responses of carbon nanotube (CNT)-reinforced nanocomposites. Jana et al. (2020) contributed by developing a numerical flattening contact model for FGM, aimed at understanding contact behavior during loading and unloading, along with an exploration of the impact of elastic and plastic gradation parameters on contact behavior. In the realm of nanocomposites, carbon nanotubes (CNTs) play a crucial role due to their exceptional mechanical properties. Shen (2009) explored FGMs graded with CNTs, and bending study conducted in a thermal environment. Bhadra et al. (2022, 2023, 2023a) contributed by developing a flattening and indentation contact model for CNT-Al nanocomposites to understand the effect of CNTs in the nanocomposite. Zghal et al. (2020) utilized Finite Element Method (FEM) to investigate the effects of geometrical features, CNT distribution type, and volume percentages of CNT on the nonlinear deflection behavior of FG-CNTRC plates. Soni et al. (2022) specifically concentrated on FG CNT in their state-of-the-art article. Notably, the literature reveals a predominant focus on vibration, deflection, and related analyses in the context of FGMs, also very few research has been conducted on contact analysis of CNTs based nanocomposite, whereas there is a dearth of research on CNTs reinforced in the FGM matrix material.