Master Dissertations

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    Performance Assessment of Mechanical and Corrosion Behavior of Additive Manufactured PLA Structure for Marine Application
    (Indian Maritime University, Kolkata Campus, 2025) V, Vishnu N; Kumar, Dhiraj; Shukla, Amarish Kumar
    Additive Manufacturing (AM) finds its applications in shipbuilding sector due to its potential to produce lightweight, customizable components and on-demand components. In the current study, PLA specimens have been fabricated using FDM based on a Design of Experiments approach. In this regard, in the current paper, the experimental study, mathematical modeling and the optimization of the PLA 3D printed structure has been discussed. The input process parameters investigated are layer thickness (LT), printing speed (PS), and infill density (ID) and the response is the ultimate tensile strength (UTS) and the specific strength. Print orientation for all specimens was horizontal with a grid infill pattern. Systematic experiments and analysis are carried out to build up the mathematical equations and explore the effect of the process parameters on the responses. Besides mechanical characterization, the corrosion performance of the 3D-printed PLA specimens was analysed in a 3.5 wt. % NaCl solution to assess their suitability for marine applications. Artificial intelligence teaching learning-based optimization (TLBO) algorithm, particle swarm optimization (PSO) algorithm and desirability function analysis (DFA) based optimization technique is used to enhance the mechanical property and response as per the requirement. Of which the TLBO showed higher precision and better global optima convergence, such as the maximum UTS (51.02 MPa) and specific strength (41.6 kNm/kg). In comparison, PSO and DFA yielded slightly lower performance. Corrosion analysis showed that samples printed with higher infill densities resulted in improved corrosion resistances and so a clear relationship between print parameters and degradation behaviour was clearly demonstrated. The work highlights the significance of the process parameter choice for the enhancement of the structure and the environmental behavior of the PLA components.
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    Biochar Reinforcement in Epoxy Composites for Enhanced Mechanical Properties and Fire Resistance
    (Indian Maritime University, Kolkata Campus, 2025) K, Vishnu Anilkumar
    In response to the growing need for environmentally sustainable and high-performance composite materials, this study explores the use of bamboo-derived biochar as a reinforcing filler in epoxy resin composites. Bamboo was selected due to its rapid renewability, abundant availability, and high lignocellulosic content, making it a viable precursor for biochar production through pyrolysis. Biochar was synthesized via slow pyrolysis at 500°C and integrated into epoxy resin at varying weight percentages (1%, 3%, and 5%) to evaluate its impact on mechanical, thermal, and fire-retardant properties. The fabricated composites were subjected to tensile testing, where the 5 wt% biochar-reinforced composite exhibited the highest performance, achieving an ultimate tensile strength (UTS) of 47.90 MPa, compared to 28.00 MPa in the neat epoxy. Young’s modulus increased from 1.85 GPa (0% biochar) to 2.42 GPa (5% biochar), indicating a significant enhancement in stiffness. Elongation at break showed a marginal decrease with increasing filler content, highlighting the typical trade-off between strength and ductility. Thermogravimetric Analysis (TGA) demonstrated improved thermal stability in composites containing biochar. The 5 wt% biochar sample showed a higher decomposition onset temperature and a residual mass of 38% at 800°C, compared to only 0.6% in the control sample. This indicates strong thermal barrier effects due to char formation. Although direct cone calorimetry testing could not be performed, a detailed review of similar studies and comparative interpretation with TGA data suggested improved flame retardancy with increased biochar content. Key inferred outcomes included longer time to ignition, reduced peak heat release rate (PHRR), and higher char residue, particularly in the 5 wt% composite. This investigation validates the multifunctional role of bamboo biochar in enhancing tensile strength, thermal stability, and flame-retardant behavior of epoxy composites. The findings support the use of such bio-based reinforcements in marine structural components, interior panels, and thermally sensitive applications. Moreover, this work opens future directions in optimizing pyrolysis conditions, scaling fabrication processes, and validating long-term durability and fire performance in real-world environments.
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    Study on The Behavior of Light on Erosion in Epoxy Coating on SS316L
    (Indian Maritime University, Kolkata Campus, 2025) Das, Nattath Sreejith; Das, Nachiketa; Kolakoti, Aditya
    This research employs optical analysis, and light intensity analysis with, three coating systems—pure epoxy, epoxy with 0.1 wt.% graphene, and epoxy with 1 wt.% graphene—were systematically evaluated for their erosion resistance and optical characteristics on SS316L stainless steel substrates. The coating thicknesses ranged from 85 µm to 103 µm, with erosion factor calculated as the reduction from the maximum thickness (103 µm). Pure epoxy exhibited the highest erosion factor of 18 µm, followed by 11 µm for epoxy + 0.1% graphene, and as low as 5 µm for epoxy + 1% graphene, indicating improved erosion resistance with increasing graphene content. Surface roughness (Ra) measurements showed a corresponding rise due to erosion, increasing from approximately 0.33 µm to 1.12 µm for pure epoxy, whereas the increase was limited from 0.19 µm to 0.45 µm in epoxy + 1% graphene coatings, highlighting the protective advantage of graphene modification. Optical analysis using RGB light filters further revealed a progressive increase in deviation values with erosion severity, where pure epoxy exhibited a maximum deviation of 0.165 at highest erosion, compared to only 0.025 for epoxy + 0.1% graphene and 0.008 for epoxy + 1% graphene at lower erosion levels. Additionally, the Energy Index (Ep), sensitive to nanoscale surface roughness, demonstrated a strong inverse correlation with Ra (Pearson Linear Correlation Coefficient, PLCC = 0.91; Mean Absolute Error, MAE = 10.7 nm), while the Structural Color Aliasing Index (SCY) effectively captured macro-level degradation, showing higher correlation (PLCC = 0.93) and a MAE of 0.12 µm. These findings not only confirm the erosion mitigation capability of graphene-reinforced coatings but also establish a robust foundation for non-destructive, real time optical monitoring of coating health using structured light and digital image-based metrics.
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    Condition Monitoring of Lubricating Oil used in Marine Vessels
    (Indian Maritime University, Kolkata Campus, 2025) Kumar, Ajay; Mishra, Deepak
    The reliability and efficiency of marine propulsion systems heavily depend on the condition of lubricating oil, which serves as both a protective and functional medium for critical engine components. Over time, lubricating oil undergoes degradation due to thermal stress, oxidative reactions, contamination, and prolonged usage. Traditional oil condition monitoring techniques primarily focus on viscosity changes, spectroscopic analysis, and chemical composition assessments. However, in recent years, polarization current analysis has emerged as a promising diagnostic tool for evaluating the dielectric integrity and degradation behaviour of lubricating oils in marine applications. This study explores the application of polarization current measurement as an effective method for monitoring the deterioration of lubricating oil used in marine vessels. The research involves subjecting lubricating oil samples to controlled thermal aging at varying temperatures (40°C, 50°C, 60°C) over extended periods to simulate real operational stress conditions. By applying a 500 V DC voltage using an insulation tester, the resulting polarization current behaviour is recorded and analyse providing valuable insights into molecular breakdown and insulation capacity loss. Experimental findings indicate that as the thermal aging process progresses, the polarization current exhibits increasing magnitudes, signifying a reduction in the resistivity of the lubricating oil. This behaviour aligns with the formation of conductive degradation byproducts such as free radicals, oxidation compounds and polar contaminants, which alter the dielectric properties of the oil. Notably, samples exposed to higher temperatures (50°C and above) demonstrate significant fluctuations in polarization current, suggesting a higher degree of dielectric instability and lubricant deterioration.
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    Experimental Study of SMAW on DSS 2205 and SS 316L for Marine Applications
    (Indian Maritime University, Kolkata Campus, 2024) Kumar, Ritesh; Kumar, Dhiraj
    Maritime-grade stainless steel, such as Duplex 2205 and 316L, is widely utilized in shipbuilding constructions, cargo tanks, offshore oil rig platforms, and many other maritime sectors. Austenitic and duplex stainless steels are also widely used in a variety of manufacturing industries and other domains. Because of its unique structural combination of ferrite and austenite grains, it has various benefits like high strength, excellent toughness, and resistance to pitting, crevice corrosion, and stress corrosion cracking. In the present study, shielded metal arc welding is used to weld two dissimilar materials DSS 2205 and SS 316L of dimension 60 mm x 60 mm x 2 mm. Two different types of electrodes such as ER2209 and E316L-16 is used to perform the welding, and also the current are varied from 80A to 100A at constant voltages of 24V to investigate the weld quality characteristics. A detailed investigation was conducted into the effects of electrodes and current on the mechanical characteristics and microstructure of welded specimens. Furthermore, the weld deposition has been investigated by weighing the welded sample before and after welding. The results shows that weld deposition initially increases with an increase of welding current from up to 90A, and then it declines from 90 to 100A. Moreover, transient thermal analysis based on FEM is performed by using ANSYS software, and simulated temperature of weld zone is obtained. Infrared thermal imager is used to capture the actual temperature of weld zone. The actual temperature obtained from thermal imager also validates the simulated temperature. Based on micrograph, martensite and austenite formation has been observed in the duplex stainless steel region and ferrite and cementite has been observed in 316L stainless steel region. This thesis is divided into six chapters. The first chapter provides an overview of steel welding and its applications across various fields, with a focus on the distinguishing features of SMAW welded samples of DSS 2205 and 316L stainless steel. Chapter 2 reviews the literature on various stainless steel processing techniques and the properties of DSS 2205 and 316L stainless steel, including microstructural, mechanical, and thermal analyses using the Ansys software, and their applications. Then, it identifies gaps in the existing literature and sets targets for addressing problem identification. Chapter 3 details the materials and procedures used in this study and discusses the various characterization strategies employed. Chapter 4 presents the results and discussion of SMAW welded DSS 2205 and 316L stainless steel, including an in depth investigation into how changes in current and electrodes affect the mechanical properties of these materials. Additionally, this chapter uses the Ansys software tool to study temperature distribution and heat flux during the welding of DSS 2205 and 316L stainless steel. Finally, viii Chapter 5 provides a comprehensive summary of the study, along with an exploration of the future scope and additional possibilities for ongoing research on SMAW welded DSS 2205 and 316L stainless steel.
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    Study on Some Mechanical and Electrical Aspects of Erosion of Epoxy Coating Applied on 316L Stainless Steel
    (Indian Maritime University, Kolkata Campus, 2024) Kumar, Rajan; Das, Nachiketa; Shukla, Amarish Kumar
    Pure epoxy coatings and epoxy-graphene composite coatings are widely recognized for their protective properties, particularly when applied to stainless steel surfaces. This study investigates key parameters of these coatings applied to SS316L stainless steel by using the dip coating method. The research aims to enhance the understanding of coating characteristics such as coating thickness, surface roughness, capacitance, insulation resistance, and impedance were measured to evaluate the performance of both pure epoxy and epoxy-graphene composite coatings. Stainless steel SS316L is extensively used in various industries due to its excellent corrosion resistance and mechanical properties. However, to further enhance its durability and performance, protective coatings are often applied. Epoxy coatings are known for their good adhesion, chemical resistance, and mechanical strength. Incorporating graphene into epoxy coatings can potentially enhance their electrical conductivity, as well as their barrier properties. The study highlights the erosion of coating and the variation of parameters such as coating thickness, surface roughness, capacitance, insulation resistance, and impedance. The inclusion of graphene in epoxy coatings demonstrated notable variation of capacitance and insulation resistance. Additionally, impedance measurements indicated better electrical stability for graphene-enhanced coatings. The composite coatings showed increased coating thickness and reduced surface roughness, which contributed to variation in various electrical parameters. Additionally, the capacitance and insulation resistance values of the epoxy-graphene coatings were significantly improved, indicating enhanced electrical insulation. Impedance measurements further confirmed the superior barrier properties of the composite coatings.
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    A Study in Friction Stir Welding on Marine Grade Dissimilar Metals
    (Indian Maritime University, Kolkata Campus, 2024) C, Harshit; Chakraborty, Sadananda
    Friction Stir Welding is an advanced technique for joining dissimilar materials, mitigating traditional welding issues like solidification cracking and distortion. This study explores friction stir welding for marine-grade Aluminium Alloy 6063-T4 (AL6063-T4) and Magnesium Alloy AZ31B (MG AZ31B), highlighting their lightweight and corrosion-resistant properties suitable for marine environments. Chapter 1 provides a comprehensive background, goals, and benefits of the study. It includes detailed analyses of relevant journal articles and modifications of general articles pertinent to this project. To improve both the weld quality and the efficiency of the friction stir welding process. Chapter 2 goes into detail about Tool geometry which is critically examined to enhance weld quality and friction stir welding efficiency. Steady-state temperature analysis identifies the optimal tool shape using "SolidWorks" for superior mechanical and thermal performance. The tool assembly includes a high-speed steel (HSS) drill bit and an H13 tool steel shoulder. In Chapter 3 a custom vertical milling machine welds two alloy plates, modelled independently in ANSYS for thermal analysis. The study uses SOLID70 elements for three dimensional thermal analysis, with precise boundary conditions to ensure accurate predictions. A tetrahedral mesh captures high-temperature gradients and stress concentrations, providing insights into deformation, stresses, temperature, and welding properties. In Chapter 4, AL 6063-T4 and MG AZ31B alloys are joined using friction stir welding, with specific surface preparation and butt joint configurations. Mechanical testing includes Vickers microhardness and tensile tests, revealing variations in joint hardness and intricate stress-strain behaviours. Failure analysis identifies TMAZ as the primary failure site, emphasizing its diverse texture structures and fracture initiation. Chapter 5 focuses on optimizing hardness and tensile strength through experimental and Computational Fluid Dynamics (CFD) analysis. ANOVA assesses the impact of rotational and travel speeds on tensile strength, finding rotational speed significantly influences tensile strength. Verification runs confirm the effectiveness of optimized parameters, with minor discrepancies suggesting areas for CFD model improvement. Lastly, friction stirs welding successfully welds 6063 T4 and AZ31B alloys at 430–490°C, enhancing microhardness and joint integrity. While joint tensile strength is lower than base materials, optimization at 1120 rpm and 63 mm/min improves yield strength. Future research should explore microstructural analysis, material innovation, application-specific studies, environmental impact, and standardization, underscoring friction stir welding's potential across various sectors.
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    Numerical analysis of flow characteristics of a fluid flowing through an orifice in a marine piping system
    (Indian Maritime University, Kolkata Campus, 2024) Maji, Avijit; Saha, Sujay
    Over the last few decades expensive research work has been performed by many researchers on the monitoring of rate of fluid flow through various pipes. Moreover, in the marine industry, it's important to conduct a detailed analysis of the uncertainties associated with flow measurement. It has been also seen that the coefficients, which are used for orifices are based on empirical data. Therefore, accurately predicting the impact of complex geometry and flow separation from the orifice in the flow have become crucial challenges for many researchers. From the review of the literature, it has been noted that a systematic detailed investigation of the flow through the orifice has not been done so far. Thus, in the present study a systematic details numerical investigation has been conducted for incompressible turbulent flow of water through a square edge orifice plate with considering various Reynolds numbers ranging from 153 to 273 and Bita ratios from 0.3432 to 0.6289. The standard design of ISO 5167-2 has been used in the present investigation. In this work, the simulations have been performed by using the ANSYS Fluent. The standard k-ε model has been selected for the turbulence flow analysis. The streamline contour, velocity contour, pressure contour, centreline axial velocity, wall pressure, radial profile of turbulent kinetic energy, and turbulent dissipation rate are presented in the results and discussion section in a systematic manner. From the analysis, it has been noted that the pressure drops from the orifice plate up to the vena contracta increase with increasing the Reynolds numbers and the beta ratio. It has also been observed that the pressure affects the jet-like flow in the core region, the recirculation zone, the reattachment, and the shear regions on the downstream side of the orifice. The location of vena contracta is also be estimated from present CFD simulations. Thus, this analysis improves the accuracy of coefficients. Consequently, error may be minimized in view of monitoring the rate of fluid flow in marine systems.
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    The role of inland container depot (ICD) in enhancing maritime supply chain efficiency
    (Indian Maritime University, 2025-05-27) Pareek, Shekhar
    This project looks into how dry ports and inland container depots (ICDs) can improve the efficiency of the maritime supply chain and relieve congestion in India's coastal ports. It evaluates how ICDs integrate multimodal transport, reduce port bottlenecks, and cut logistics costs in light of India's thriving trade. In addition to identifying operational challenges and best practices, the objectives involve evaluating the effects of ICD on seaport congestion, cargo flow, and cost efficiency.
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    A study on the shipping accidents in restricted water (Suez Canel and Panama Canal)
    (Indian Maritime University, 2025-05-27) Chahande, Sahil