Faculty Publications
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Item Impact Energy Estimation of AISI304L/AA6063 Alloys Dissimilar Friction Welds Influenced by Various New Faying Surfaces: A Comparative Study(Springer, 2024) Senthil Murugan, S.S.; Paulraj, P.; Kattimani, S.This research paper delves into an innovative approach for enhancing the faying surfaces in the rotary friction welding process. This study evaluates the impact energy in Joule (J) of friction-welded joints (FWJs) between dissimilar cylindrical rods made of AA6063 wrought aluminium and AISI304L austenitic stainless steel focusing on the influence of various faying surface designs and welding parameters. Additionally, the study conducts an in-depth analysis of various faying surface designs. A series of experiments were conducted using a Charpy V-notch tester to analyse 45 different FWJs with diverse surface modifications. Welding conditions such as friction pressure (FP), friction time, and upset pressure were varied to assess their effects on joint toughness. The aim was to utilize the low FP, spanning from 1.2 to 1.8 MPa, in the pursuit of optimizing the welding process. The results revealed notable variations in the impact energy values of FWJs in response to changes in both the faying surfaces of the specimens and the welding parameters. A5 trial achieved the highest impact energy at 38 J. Notably, joints with hemispherical faying surfaces exhibited enhanced toughness, with method N achieving 26 J. Adjustments to the faying surface design and welding conditions had a substantial impact on the toughness and energy absorption of the welded joints. © The Institution of Engineers (India) 2024.Item INVESTIGATION OF SINGLE-SIDED TIG WELDING IN DISSIMILAR AISI 316L AND 304L STAINLESS STEEL JOINTS(Galati University Press, 2025) Senthil Murugan, S.S.; Kattimani, S.; Saminathan, R.; John Iruthaya Raj, M.J.I.This study investigates the Tungsten Inert Gas (TIG) welding of dissimilar austenitic stainless steels, AISI 304L and AISI 316L, each with a thickness of 3.2 mm. A single-pass butt joint was welded using a 100 A current with argon shielding gas. The joints underwent mechanical testing, including tensile, bend, impact, and hardness tests. The tensile test revealed a 25% reduction in the weld joint strength compared to the base metal, primarily due to differences in thermal expansion and mechanical properties, resulting in an overall joint efficiency of 75%. Macro and microstructural analyses indicated good fusion without defects, and typical weld metal microstructures were observed. The heat-affected zone (HAZ) of AISI 304L showed larger grains, while AISI 316L exhibited a flaky structure. The hardness test indicated the highest value in the weld zone (191 HV), compared to the HAZ (177 HV) and the parent metal (170 HV), which can be attributed to grain refinement and the use of the SS304 filler rod. Impact tests demonstrated good impact resistance (45 J), with the HAZ exhibiting higher toughness compared to the parent metal. Bend tests revealed no cracks on the weld face, whereas cracks were observed in the root bend tests. The study demonstrated sufficient strength, toughness, and hardness in the dissimilar TIG joint for engineering applications, despite the reduced tensile strength compared to the base metals. © Galati University Press, 2025.Item Analysis of 3D-Printed Nylon/PETG Hybrid Polymer Laminate Plate for Wind Turbine Nacelle Application(Springer, 2025) Senthil Murugan, S.S.; Shankar, E.; Kattimani, S.; Abish, V.R.; Anbu, G.; Avinash, A.R.This study aims to develop hybrid polymer laminate (HPL) structure utilizing the 3D printing fused filament fabrication (FFF) method and analyze the printing process. The HPL plates were fabricated using PETG and nylon 66 thermoplastic polymers at varying infill densities, printing speeds, and layer thicknesses. The experimental setup followed a fixed matrix based on the L9 orthogonal array (OA). Each HPL consisted of a bottom layer printed with nylon 66, with PETG layers sandwiched on top. Subsequently, the samples underwent testing using a UTM m/c to assess their tensile and flexural strength, as well as printing efficiency. Warping was observed on the printed samples, with a maximum tensile strength of 27 MPa and flexural strength of 14.5 MPa recorded. Notably, different strength values were observed when altering printing parameters. While the printing process was successful, the resulting HPL exhibited slightly lower strength compared to PETG or nylon 66 filaments. The study achieved a maximum printing efficiency of 90% (?), with the layer thickness parameter significantly impacting tensile properties. These findings offer valuable insights and required for various industrial applications, including wind turbines, electronics, automotive, and aeronautics. © The Author(s), under exclusive licence to The National Academy of Sciences, India 2024.Item Effect of piezoelectric ceramic on natural frequency, structural, and thermal properties of additively manufactured PLA/BTO composite structure(Elsevier Ltd, 2025) Senthil Murugan, S.S.; Kattimani, S.This study investigates the fabrication and characterisation of filaments and 3D-printed samples using polylactic acid (PLA) and PLA/BTO (Barium Titanate) composites via fused deposition additive manufacturing (FDAM). PLA/BTO composite filaments were prepared by blending PLA granules with BTO particles using hot extrusion. Samples were 3D printed under controlled parameters and analyzed for dynamic, thermal, and structural properties. The inclusion of BTO significantly enhanced natural frequency (11 Hz-first peak) and structural rigidity compared to pure PLA (8 Hz-first peak), particularly under cantilever beam configurations. Microstructural analysis via optical and field emission scanning electron microscopy (FESEM) revealed uniform particle dispersion and good layer adhesion in composites with a peak width of 340 ?m. Energy-dispersive X-ray diffraction (EDS) study insisted that the presence of BTO improves functionality with minimal reinforcement with other trace elements. X-ray diffraction (XRD) confirmed increased crystallinity in PLA/BTO samples and improved alignment of the crystalline regions post-FDAM process, while Fourier transform infrared spectroscopy (FTIR) demonstrated molecular interactions between PLA and BTO and highlights the structural modifications in the composite due to the act of BTO reinforcement as nucleating agent. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) highlighted enhanced thermal stability and modified crystallinity due to BTO incorporation. Printed PLA/BTO demonstrates the highest resistance to thermal degradation than pure PLA, with degradation onset at an elevated temperature. Results validate the suitability of PLA/BTO composites for applications requiring tailored dynamic, thermal, and structural properties, emphasizing the FDAM process's potential for advanced material development. © 2025 Elsevier Ltd and Techna Group S.r.l.Item Investigation of dielectric properties and shore hardness of 3D-printed PLA core sandwich disc with functional ceramics surface cladding(KeAi Publishing Communications Ltd., 2025) Senthil Murugan, S.S.; Kattimani, S.; Bharadwaj, N.Poly-lactic acid (PLA), a popular biodegradable polymer for 3D printing, has limited dielectric strength and surface hardness, restricting its use in advanced electronic and structural applications. Existing enhancement methods are often complex or yield inconsistent results. Therefore, a straightforward and scalable approach is necessary to enhance the properties of 3D-printed PLA. This study aims to explore the enhancement of the dielectric and surface hardness of printed PLA discs through surface cladding using nano-functional ceramics and graphene for next-generation multifunctional applications. PLA discs were fabricated via Fused Deposition Modelling (FDM) and subsequently cladded using hand layup with Araldite resin as a binder. Cladding materials included cobalt ferrite (CF), barium titanate (BTO), and graphene (Gr), individually and in combinations. Dielectric properties—capacitance, impedance, dielectric constant, dielectric loss, dissipation factor, and AC conductivity—were analyzed using an impedance analyzer, while surface hardness was measured using a Shore-D durometer. Results revealed that cladding led to uniform particle dispersion with effective surface bonding, improved dielectric performance, and significantly enhanced surface hardness. The CF + BTO + Gr combination exhibited superior dielectric behaviour, balancing high polarization with low energy dissipation, while BTO contributed to an enhanced dielectric constant and graphene improved charge transfer. All cladded samples showed frequency-dependent dielectric responses, with stability at higher frequencies. The highest surface hardness was achieved with CF + BTO, attributed to rigid, uniform reinforcement. © 2025 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltdé This is an open access article under the CC BY-NC-ND license. http://creativecommons.org/licenses/by-nc-nd/4.0/Item Surface characteristics of 3D-printed PLA/BTO piezo-polymer composite(Springer Science and Business Media Deutschland GmbH, 2025) Senthil Murugan, S.S.; Kattimani, S.3D printing has emerged as a transformative technology for fabricating multiphase composite materials with tailored properties for advanced industrial applications. However, the influence of functional particle reinforcement on the surface morphology of printed bioplastics remains underexplored. This study addresses the research question: How does the incorporation of piezoelectric barium titanate (BaTiO3, BTO) particles affect the surface characteristics of 3D-printed poly-lactic acid (PLA) composites? To investigate this, a novel bioplastic composite filament was developed by extruding PLA with BTO particles, and composite specimens (PLBT) were fabricated using a 3D printing method-fused filament fabrication (FFF). A comprehensive surface characterization was performed using 3D non-contact profilometry, analyzing parameters including line and areal surface roughness, furrow formation, isotropy, peak count histograms, polar angle circular mean, mean resultant length (MRL), and Bearing Area Curve (BAC). Comparative analysis between pure PLA and PLBT samples, as well as between their top and bottom printed surfaces, revealed that the inclusion of BTO particles significantly altered the deposition behavior, resulting in increased surface roughness and distinct topographical features. Specifically, average surface roughness values increased from 8.2 µm in pure PLA to 15.8 µm in PLBT composites. The top surfaces of PLBT samples exhibited smoother textures with smaller peaks and valleys, which are advantageous for wear-sensitive applications. These findings contribute to the limited body of knowledge on the surface behavior of 3D-printed functional composites and highlight the critical role of particle reinforcement in tuning surface performance for application-specific demands. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.