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Dr. Sagil James
California State University Fullerton

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0 Manufacturing
0 Manufacturing & Process Optimisation
0 advanced manufacturing
0 material sciences
0 Advanced Manufacturing (3D Printing Technology)

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Original article
Published: 19 September 2020 in The International Journal of Advanced Manufacturing Technology
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An extensive investigation into thermal stress mitigation of high-speed machining (machining speeds exceeding 3800 rpm) of hybrid composite stacks using nanoparticle-enhanced minimum quantity lubrication (MQL) is presented and discussed. Ten different interface machining conditions are examined using five different nanoparticles, namely Al2O3, 1%SWCNT, 1%MWCNT, Ni, and Al. Interface roughness measurements are recorded, and thermal stress effects are collected via digital microscopy images. Nanoparticle-enhanced MQL (NEMQL) chemical and physical properties in the form of viscosity and heat transfer capabilities are discussed in accordance with vegetable oil–based MQL. Two different vegetable oils are utilized in a 1:1 ratio to explore viscous effects in the NEMQL suspension and their respective cooling capabilities from conventional forms of machine cooling. Furthermore, the results indicate 2.5%vol Al2O3 + MQL showed the best interface roughness improvements by over 170% from the standard control dry machining of carbon fiber–reinforced polymer (CFRP) and titanium (Ti) hybrid composite stacks. Moreover, the results indicated 1%SWCNT + MQL showed the best interface roughness improvement by over 100% for CFRP and aluminum (Al) hybrid composite stacks from the standard control: dry machining. Chemical and physical properties of the NEMQL, such as thermal conductivity, viscosity, and convective heat transfer capabilities, explain to some extent the results depending on the hybrid composite stack application. The results of this experiment provide insight that NEMQL is a promising cooling lubrication method for conventional manufacturing processes in a wide array of industrial applications. The results of this study are expected to open new possibilities for eco-friendly and cost-effective methods for a high-speed cold saw cutting in advanced engineering materials.

ACS Style

Sagil James; Shayan Mohammad Nejadian. Experimental study on high-speed saw cutting of hybrid composite stacks using nanoparticle-enhanced minimum quantity lubrication. The International Journal of Advanced Manufacturing Technology 2020, 110, 3077 -3090.

AMA Style

Sagil James, Shayan Mohammad Nejadian. Experimental study on high-speed saw cutting of hybrid composite stacks using nanoparticle-enhanced minimum quantity lubrication. The International Journal of Advanced Manufacturing Technology. 2020; 110 (11-12):3077-3090.

Chicago/Turabian Style

Sagil James; Shayan Mohammad Nejadian. 2020. "Experimental study on high-speed saw cutting of hybrid composite stacks using nanoparticle-enhanced minimum quantity lubrication." The International Journal of Advanced Manufacturing Technology 110, no. 11-12: 3077-3090.

Journal article
Published: 01 July 2020 in Vibration
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Suspension dampers are extremely critical for modern automobiles for absorbing vibrational energy while in operation. For years now, the viscous passive damper has been dominant. However, there is a constant need to improve and revolutionize the damping technology to adapt to modern road conditions and for better performance. Controlled shock absorbers capable of adapting to uneven road profiles are required to meet this challenge and enhance the passenger comfort level. Among the many types of modern damping solutions, magnetorheological (MR) dampers have gained prominence, considering their damping force control capability, fast adjustable response, and low energy consumption. Advancements in energy-harvesting technologies allow for the regeneration of a portion of energy dissipated in automotive dampers. While the amount of regenerated energy is often insufficient for regular automobiles, it could prove to be vital to support lightweight battery-operated vehicles. In battery-operated vehicles, this regenerated energy can be used for powering several secondary systems, including lighting, heating, air conditioning, and so on. This research focuses on developing a hybrid smart suspension system that combines the MR damping technology along with an electromagnetic induction (EMI)-based energy-harvesting system for applications in lightweight battery-operated vehicles. The research involves the extensive designing, numerical simulation, fabrication, and testing of the proposed smart suspension system. The development of the proposed damping system would help advance the harvesting of clean energy and enhance the performance and affordability of future battery-operated vehicles.

ACS Style

Urvesh Kabariya; Sagil James. Study on an Energy-Harvesting Magnetorheological Damper System in Parallel Configuration for Lightweight Battery-Operated Automobiles. Vibration 2020, 3, 162 -173.

AMA Style

Urvesh Kabariya, Sagil James. Study on an Energy-Harvesting Magnetorheological Damper System in Parallel Configuration for Lightweight Battery-Operated Automobiles. Vibration. 2020; 3 (3):162-173.

Chicago/Turabian Style

Urvesh Kabariya; Sagil James. 2020. "Study on an Energy-Harvesting Magnetorheological Damper System in Parallel Configuration for Lightweight Battery-Operated Automobiles." Vibration 3, no. 3: 162-173.

Journal article
Published: 23 June 2020 in Procedia Manufacturing
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Cold Spray (CS) process is a solid-phase metal deposition technique capable of depositing micro to nanosized particles on a substrate without melting the particles. The CS process thus retains the original mechanical and chemical properties of the coating material. Residual stresses are an important factor affecting the quality, strength, and performance of the coated substrate in CS process. Currently, there is a lack of clear understanding of the residual stress generation in CS process and its control measures. Existing studies have not investigated the type III residual stress in CS process. This study attempts to investigate the effects of impact velocity and angle of impact on the Type III residual stress generation in CS process using molecular dynamics simulation technique. The study considers the impact of nanosized copper particles on copper substrate and the magnitude of the residual stresses is monitored. It is seen that the coated surface retains both tensile and compressive residual stresses. A higher angle impact shows higher compressive residual stresses, which are beneficial to industrial applications. Similarly, 400 m/s impact velocity showed the highest distribution of compressive residual stress on the body. The study results would be crucial in extending the industrial applications of the CS process.

ACS Style

Sagil James; Karan Shah. Effect of Velocity and Impact Angle on Residual Stress Generation in Cold Spray Process – A Molecular Dynamics Simulation Study. Procedia Manufacturing 2020, 48, 776 -780.

AMA Style

Sagil James, Karan Shah. Effect of Velocity and Impact Angle on Residual Stress Generation in Cold Spray Process – A Molecular Dynamics Simulation Study. Procedia Manufacturing. 2020; 48 ():776-780.

Chicago/Turabian Style

Sagil James; Karan Shah. 2020. "Effect of Velocity and Impact Angle on Residual Stress Generation in Cold Spray Process – A Molecular Dynamics Simulation Study." Procedia Manufacturing 48, no. : 776-780.

Journal article
Published: 20 April 2020 in Journal of Manufacturing Processes
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Carbon fiber reinforced plastic (CFRP) is an extremely beneficial composite material in the aerospace and automobile industries owing to its high-strength-to-weight ratio, high stiffness, lightweight, and corrosion resistance. However, CFRP material alone is limited in its weight-bearing capabilities. A thin layer material such as Titanium (Ti) is often used along with CFRP laminates to address these issues. Traditional techniques used to join CFRP/Ti stacks include the use of adhesives, glues, or rivets, and bolts. These techniques have several limitations including weight addition, stress cracking, delamination, and limited operating temperatures. These limitations can be readily addressed by the use of solid-state welding techniques based on ultrasonic energy. One such technique is the Ultrasonic Additive Manufacturing (UAM) process, which is capable of fabricating 3D structures of CFRP/Ti laminar composites. Preliminary experimental studies proved the feasibility of using the UAM process to join CFRP/Ti stacks. Further development of this process needs a detailed investigation of the process parameters. This study aims to study the effect of critical process parameters including the ultrasonic energy and pre-surface roughness on the shear strength of the fabricated CFRP/Ti stacks using the UAM process. The study found that both ultrasonic energy and surface roughness have a positive impact on the resulting shear strengths of the UAM fabricated structures.

ACS Style

Sagil James; Christopher Dang. Investigation of shear failure load in ultrasonic additive manufacturing of 3D CFRP/Ti structures. Journal of Manufacturing Processes 2020, 56, 1317 -1321.

AMA Style

Sagil James, Christopher Dang. Investigation of shear failure load in ultrasonic additive manufacturing of 3D CFRP/Ti structures. Journal of Manufacturing Processes. 2020; 56 ():1317-1321.

Chicago/Turabian Style

Sagil James; Christopher Dang. 2020. "Investigation of shear failure load in ultrasonic additive manufacturing of 3D CFRP/Ti structures." Journal of Manufacturing Processes 56, no. : 1317-1321.

Original article
Published: 06 January 2020 in The International Journal of Advanced Manufacturing Technology
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Liquid-assisted laser beam machining (LA-LBM) process is used as an alternative to existing laser beam machining (LBM) process to address the problems associated with the extreme heat of the laser. In this research, the thermal effects of laser and hydrodynamics effects of the liquid medium in the LA-LBM process are investigated to understand the complex interactions involved in the material removal during LA-LBM process. The study utilizes the versatile multiscale modeling approach by coupling the molecular and continuum domains. The research investigates the role of the water layer in the LA-LBM process along with the material transformations taking place in the water layer in the vicinity of the machined zone. The results of the study augment our existing knowledge of the complex mechanisms involved in the LA-LBM process. Investigation on cavity depth revealed the increase in material removal with the increase in laser heat. The change in water layer thickness revealed the reduction in the radius of the heat-affected zone while further explaining the nodal temperature distribution profile and electron temperature distribution in the water layer.

ACS Style

Sagil James; Aakash Patil. Study on multiscale modeling and simulation of liquid-assisted laser beam machining process. The International Journal of Advanced Manufacturing Technology 2020, 106, 3463 -3474.

AMA Style

Sagil James, Aakash Patil. Study on multiscale modeling and simulation of liquid-assisted laser beam machining process. The International Journal of Advanced Manufacturing Technology. 2020; 106 (7-8):3463-3474.

Chicago/Turabian Style

Sagil James; Aakash Patil. 2020. "Study on multiscale modeling and simulation of liquid-assisted laser beam machining process." The International Journal of Advanced Manufacturing Technology 106, no. 7-8: 3463-3474.

Journal article
Published: 18 November 2019 in Journal of Manufacturing Processes
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Hybrid composites stacks are multi-material laminates which find extensive applications in industries such as aerospace, automobile, and electronics and so on. Most hybrid composites consist of multiple layers of fiber composites and metal sheets stacked together. These composite stacks have excellent physical and mechanical properties including high strength, high hardness, high stiffness, excellent fatigue resistance and low thermal expansion. Micromachining of these materials require particular attention as conventional methods such as micro-drilling is extremely challenging considering the non-homogeneous structure and anisotropic nature of the material layers. Micro Ultrasonic Machining (μUSM) is a manufacturing process capable of machining such difficult-to-machine materials with ultraprecision. Experimental study showed that μUSM process could successfully machine hybrid composite stacks at micron scale with a relatively good surface finish. This research uses finite element simulation technique to investigate the material removal during the μUSM process for micromachining hybrid composite stacks. The effects of critical process parameters including the amplitude of vibration, feed rate and tool material on the cavity depth, cutting force and equivalent stress distribution are studied. The outcome of this research can be utilized to further our understanding of performing precision machining of hybrid composite stacks for use in several critical engineering applications.

ACS Style

Sagil James; Sagar Panchal. Finite element analysis and simulation study on micromachining of hybrid composite stacks using Micro Ultrasonic Machining process. Journal of Manufacturing Processes 2019, 48, 283 -296.

AMA Style

Sagil James, Sagar Panchal. Finite element analysis and simulation study on micromachining of hybrid composite stacks using Micro Ultrasonic Machining process. Journal of Manufacturing Processes. 2019; 48 ():283-296.

Chicago/Turabian Style

Sagil James; Sagar Panchal. 2019. "Finite element analysis and simulation study on micromachining of hybrid composite stacks using Micro Ultrasonic Machining process." Journal of Manufacturing Processes 48, no. : 283-296.

Original article
Published: 22 August 2019 in The International Journal of Advanced Manufacturing Technology
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The hybrid laminar composite stack of carbon fiber reinforced polymer (CFRP) and titanium (Ti) are widely used in several critical engineering applications, including aerospace and automobile sectors. The joining of CFRP and Ti through conventional methods has several limitations such as weight additional, material damage, and lower fatigue life. Ultrasonic additive manufacturing (UAM) is a solid-state manufacturing process capable of joining layers of dissimilar materials. Experimental studies have successfully demonstrated the welding of CFRP and Ti through UAM process. However, there is a lack of understanding of the exact bonding process and influence of process parameter on weld quality during UAM. The present study investigates the bonding process and the effects of critical parameters in the UAM process of CFRP and Ti layers using finite element analysis and simulation technique. The simulation study reveals that the CFRP/titanium stacks encounter interfacial cyclic shear stresses and shear strains. The study found that the vibrational amplitude and surface roughness of the substrates play a critical role in achieving a proper weld. The simulation results are validated using experimentation. The finding of this study can help advance the commercialization of UAM process for welding dissimilar materials and composites.

ACS Style

Sagil James; Lenny De La Luz. Finite element analysis and simulation study of CFRP/Ti stacks using ultrasonic additive manufacturing. The International Journal of Advanced Manufacturing Technology 2019, 104, 4421 -4431.

AMA Style

Sagil James, Lenny De La Luz. Finite element analysis and simulation study of CFRP/Ti stacks using ultrasonic additive manufacturing. The International Journal of Advanced Manufacturing Technology. 2019; 104 (9-12):4421-4431.

Chicago/Turabian Style

Sagil James; Lenny De La Luz. 2019. "Finite element analysis and simulation study of CFRP/Ti stacks using ultrasonic additive manufacturing." The International Journal of Advanced Manufacturing Technology 104, no. 9-12: 4421-4431.

Journal article
Published: 01 January 2019 in International Journal of Manufacturing Research
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ACS Style

Anurag Mahajan; Sagil James. Analytical Modeling and Experimental Study of Machining of Smart Materials using Submerged Abrasive Waterjet Micromachining Process. International Journal of Manufacturing Research 2019, 14, 1 .

AMA Style

Anurag Mahajan, Sagil James. Analytical Modeling and Experimental Study of Machining of Smart Materials using Submerged Abrasive Waterjet Micromachining Process. International Journal of Manufacturing Research. 2019; 14 (3):1.

Chicago/Turabian Style

Anurag Mahajan; Sagil James. 2019. "Analytical Modeling and Experimental Study of Machining of Smart Materials using Submerged Abrasive Waterjet Micromachining Process." International Journal of Manufacturing Research 14, no. 3: 1.

Journal article
Published: 19 November 2018 in Scientific Reports
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Dye-Sensitized Solar Cells (DSSC) are third generation solar cells used as an alternative to traditional silicon solar cells. DSSCs are characterized by their durability, easy handling and ability to perform better under diverse lighting conditions which makes them an ideal choice for indoor applications. However, DSSCs suffer from several limitations including low efficiencies, susceptibility to electrolyte leakage under extreme weather conditions, and the need for expensive materials and fabrication techniques which limits their large-scale industrial applications. Addressing these limitations through efficient design and manufacturing techniques are critical in ensuring that the DSSCs transform from the current small-scale laboratory levels to sizeable industrial production. This research attempts to address some of these significant limitations by introducing the concepts of nature-inspired fractal-based design followed by the additive manufacturing process to fabricate cost-effective, flexible counter electrodes for DSSCs. The new conceptual fractal-based design counter electrodes overcome the limitations of conventional planar designs by significantly increasing the number of active reaction sites which enhances the catalytic activity thereby improving the performance. The fabrication of these innovative fractal designs is realized through cost-effective manufacturing techniques including additive manufacturing and selective electrochemical co-deposition processes. The results of the study suggest that the fractal-based counter electrodes perform better than conventional designs. Additionally, the fractal designs and additive manufacturing technology help in addressing the problems of electrolyte leakage, cost of fabrication, and scalability of DSSCs.

ACS Style

Sagil James; Rinkesh Contractor. Study on Nature-inspired Fractal Design-based Flexible Counter Electrodes for Dye-Sensitized Solar Cells Fabricated using Additive Manufacturing. Scientific Reports 2018, 8, 1 -12.

AMA Style

Sagil James, Rinkesh Contractor. Study on Nature-inspired Fractal Design-based Flexible Counter Electrodes for Dye-Sensitized Solar Cells Fabricated using Additive Manufacturing. Scientific Reports. 2018; 8 (1):1-12.

Chicago/Turabian Style

Sagil James; Rinkesh Contractor. 2018. "Study on Nature-inspired Fractal Design-based Flexible Counter Electrodes for Dye-Sensitized Solar Cells Fabricated using Additive Manufacturing." Scientific Reports 8, no. 1: 1-12.

Journal article
Published: 09 August 2018 in Journal of Manufacturing and Materials Processing
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Liquid Assisted Laser Beam Micromachining (LA-LBMM) process is an advanced machining process that can overcome the limitations of traditional laser beam machining processes. This research involves the use of a Molecular Dynamics (MD) simulation technique to investigate the complex and dynamic mechanisms involved in the LA-LBMM process both in static and dynamic mode. The results of the MD simulation are compared with those of Laser Beam Micromachining (LBMM) performed in air. The study revealed that machining during LA-LBMM process showed higher removal compared with LBMM process. The LA-LBMM process in dynamic mode showed lesser material removal compared with the static mode as the flowing water carrying the heat away from the machining zone. Investigation of the material removal mechanism revealed the presence of a thermal blanket and a bubble formation in the LA-LBMM process, aiding in higher material removal. The findings of this study provide further insights to strengthen the knowledge base of laser beam micromachining technology.

ACS Style

Vivek Anand Menon; Sagil James. Molecular Dynamics Simulation Study of Liquid-Assisted Laser Beam Micromachining Process. Journal of Manufacturing and Materials Processing 2018, 2, 51 .

AMA Style

Vivek Anand Menon, Sagil James. Molecular Dynamics Simulation Study of Liquid-Assisted Laser Beam Micromachining Process. Journal of Manufacturing and Materials Processing. 2018; 2 (3):51.

Chicago/Turabian Style

Vivek Anand Menon; Sagil James. 2018. "Molecular Dynamics Simulation Study of Liquid-Assisted Laser Beam Micromachining Process." Journal of Manufacturing and Materials Processing 2, no. 3: 51.

Journal article
Published: 03 August 2018 in Procedia Manufacturing
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Cold Spray (CS) process is a deposition process in which micron-to-nano sized solid particles are deposited on a substrate using high-velocity impacts. Unlike thermal spray processes, CS process does not melt the particles thus retaining their original physical and chemical properties. These characteristics make CS process ideal for various engineering applications. Though CS process offers excellent promises, the realization of its full potential is limited by lack of understanding of the effects of critical process parameters on the deposition process. This study aims to understand the effects of critical process parameters including impact velocity, the angle of impact and particle size at atomistic scale on the coating quality involved in CS process of metal particles using Molecular Dynamics (MD) simulation technique. The focus of this study is on the coating of nanoparticles during cold spray process even though the results of this study can be extended to the micron regime because the larger particles tend to break into smaller fragments after the impact. The study found that the quality of deposition is highest for an impact velocity of 500-700 m/s, the particle size of 20 Å and an impact angle of 90°. The findings of this study can help improve the coating quality during CS process.

ACS Style

Aneesh Joshi; Sagil James. Molecular Dynamics Simulation Study on Effect of Process Parameters on Coatings during Cold Spray Process. Procedia Manufacturing 2018, 26, 190 -197.

AMA Style

Aneesh Joshi, Sagil James. Molecular Dynamics Simulation Study on Effect of Process Parameters on Coatings during Cold Spray Process. Procedia Manufacturing. 2018; 26 ():190-197.

Chicago/Turabian Style

Aneesh Joshi; Sagil James. 2018. "Molecular Dynamics Simulation Study on Effect of Process Parameters on Coatings during Cold Spray Process." Procedia Manufacturing 26, no. : 190-197.

Journal article
Published: 03 August 2018 in Procedia Manufacturing
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Vibration Assisted Nano Impact-machining by Loose Abrasives (VANILA) is a novel nanomachining process that performs target specific nano abrasive machining of hard and brittle materials. An atomic force microscope (AFM) is used as a platform in this process wherein, nano abrasives, injected in slurry between the workpiece and the vibrating AFM probe, impact the workpiece and cause nanoscale material removal. Liquid medium is required in this process to confine the abrasives within the machining zone. However, the presence of liquid medium could significantly influence the abrasive dynamics as well as the substrate deformation behavior during the VANILA process. This study focuses on understanding the effect of liquid medium on the material removal behavior during the VANILA process. A Molecular Dynamics Simulation (MDS) based study is conducted under different initial conditions with and without the presence of liquid medium (water). The results obtained from the study showed that while the water absorbs some energy from the abrasive grain, it also provides a lubricating layer to the grain preventing adhesion on the workpiece surface. Visualizations of the atomic configurations of the workpiece showed that the presence of water molecules could significantly affect the material dislocations during the impact process.

ACS Style

Sagil James; Murali Sundaram. Effects of water molecules on material removal behavior in Vibration Assisted Nano Impact-machining by Loose Abrasives - A molecular dynamics simulation study. Procedia Manufacturing 2018, 26, 552 -559.

AMA Style

Sagil James, Murali Sundaram. Effects of water molecules on material removal behavior in Vibration Assisted Nano Impact-machining by Loose Abrasives - A molecular dynamics simulation study. Procedia Manufacturing. 2018; 26 ():552-559.

Chicago/Turabian Style

Sagil James; Murali Sundaram. 2018. "Effects of water molecules on material removal behavior in Vibration Assisted Nano Impact-machining by Loose Abrasives - A molecular dynamics simulation study." Procedia Manufacturing 26, no. : 552-559.

Proceedings article
Published: 18 June 2018 in Volume 4: Processes
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An Ultrasonic Powder Consolidation is an additive manufacturing technique that utilizes high-frequency vibrations to consolidate micro/nano powder materials to fully dense and near to net-shaped parts. Unlike traditional powder consolidation techniques such as sintering, shock wave-based and pressure-based processes, the consolidation during Ultrasonic Powder Consolidation process happens at relatively low temperatures and pressures within few seconds or less. Ultrasonic Powder Consolidation process presents several inherent advantages including low power consumption, low cost and zero thermal stresses on the consolidated parts. Experimental studies have shown that Ultrasonic Powder Consolidation process is capable of successfully consolidating powders of metals and metal-matrix composites. While Ultrasonic Powder Consolidation process promises several potential applications, the mechanism of bond formation between the consolidated metal powders is not completely understood. This research uses Molecular Dynamics simulation technique to investigate the underlying bond formation and consolidation mechanisms involved in Ultrasonic Powder Consolidation process. The research also explores the effects of critical process parameters including vibration frequency, amplitude and initial temperature on the quality of the consolidated part. The study found that high-frequency vibrations cause high interfacial stresses resulting in acoustic softening and high plastic deformation of the nanoparticles. The study revealed that the overall atomistic temperature does not exceed the melting point of the material. The study also found that the vibration amplitude and frequency played a significant role in the consolidation process. Finally, the simulation study showed that the high-frequency vibration leads to large plastic deformations at ultra-high shear strain rates causing the interfacial atoms to interlock with each other resulting in high densification and consolidation. The results of this study would augment the ongoing experimental studies on Ultrasonic Powder Consolidation process which would help realize the promised potentials of this low temperature – low-pressure consolidation technique.

ACS Style

Sagil James; Prashanth Rajanna. Molecular Dynamics Simulation Study of Ultrasonic Powder Consolidation Process. Volume 4: Processes 2018, 1 .

AMA Style

Sagil James, Prashanth Rajanna. Molecular Dynamics Simulation Study of Ultrasonic Powder Consolidation Process. Volume 4: Processes. 2018; ():1.

Chicago/Turabian Style

Sagil James; Prashanth Rajanna. 2018. "Molecular Dynamics Simulation Study of Ultrasonic Powder Consolidation Process." Volume 4: Processes , no. : 1.

Proceedings article
Published: 18 June 2018 in Volume 4: Processes
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Carbon fiber reinforced plastic (CFRP) are advanced engineering materials which are recognized as the most sought-after composite for several industrial applications including aerospace and automotive sectors. CFRP have superior physical and mechanical properties such as lightweight, high resilience, high-durability and high strength-to-weight ratio. CFRP composites stacked up with titanium to form multi-layered material stacks to enhance its load bearing capability. Traditional methods of stacking up CFRP and titanium involves using either high strength adhesives or rivets and bolts. The laminate structures joined by these methods often tend to fail during high load-bearing applications. Conventional metal welding technologies use high heat causing high thermal stresses and microstructural damages. Ultrasonic welding is a solid-state joining process, which has the capability of welding dissimilar materials at relatively low temperatures using ultrasonic vibration. Ultrasonic additive manufacturing (UAM) process is an ideal method to weld CFRP and Titanium. During the ultrasonic welding process, two dissimilar materials under a continuous static load are subjected to transverse ultrasonic vibrations, which results in high stress and friction between the two surfaces. This research focuses on the study of ultrasonically welding CFRP and Titanium stacks using UAM process. The study involves experimentation performed on an in-house built UAM setup. Finite element analysis is performed to understand the distribution stresses and strains during the UAM process. In this study, CFRP and Titanium layers are successfully welded using UAM process without causing any melting or significant heating. The finite element analysis study revealed that during UAM process, CFRP/Titanium stacks are subject to repeated cyclic shear stress reversals resulting in a strong weld joint. The stress-strain diagram during the process showed a considerable increase in plastic strain during the UAM process. The outcomes of this study can be used to further the industrial applications of the ultrasonic additive process as well as other ultrasonic welding based processes involving dissimilar materials.

ACS Style

Sagil James; Abhishek Sonate; Christopher Dang; Lenny De La Luz. Experimental and Simulation Study of Ultrasonic Additive Manufacturing of CFRP/Ti Stacks. Volume 4: Processes 2018, 1 .

AMA Style

Sagil James, Abhishek Sonate, Christopher Dang, Lenny De La Luz. Experimental and Simulation Study of Ultrasonic Additive Manufacturing of CFRP/Ti Stacks. Volume 4: Processes. 2018; ():1.

Chicago/Turabian Style

Sagil James; Abhishek Sonate; Christopher Dang; Lenny De La Luz. 2018. "Experimental and Simulation Study of Ultrasonic Additive Manufacturing of CFRP/Ti Stacks." Volume 4: Processes , no. : 1.

Proceedings article
Published: 18 June 2018 in Volume 4: Processes
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Liquid Assisted Laser Beam Micromachining (LA-LBMM) process is advanced machining process which can overcome the limitations of traditional laser beam machining processes. LA-LBMM process uses a layer of a liquid medium such as water above the substrate surface during the application of laser beam. During LA-LBMM process, the liquid medium is used both in static mode in which the water is still or in a dynamic mode in which the water flows over the substrate with a specific velocity. Experimental studies on LA-LBMM process have shown that the cavity machined has a better surface finish due to a reduction in the amount of re-deposition and recast material. While LA-LBMM process promises significant improvement in laser-based micromachining applications, the process mechanisms involved in LA-LBMM process is not well understood. In the past, finite element simulation studies on LA-LBMM process is studied which could only find the temperature distribution on the substrate during machining. A clear understanding of the role of water medium during the LA-LBMM process is lacking. This research involves the use of Molecular Dynamics (MD) simulation technique to investigate the complex and dynamic mechanisms involved in the LA-LBMM process both in static and dynamic mode. The results of the MD simulation are compared with those of Laser Beam Micromachining (LBMM). The study revealed that machining during LA-LBMM process showed higher removal compared with LBMM process. The LA-LBMM process in dynamic mode showed lesser material removal compared with static mode as the flowing water carrying the heat away from the machining zone. Formation of nanoscale bubbles along with shockwave propagation is observed during the simulation of LA-LBMM process. The findings of this study provide further insights to strengthen the knowledge base of LA-LBMM process.

ACS Style

Sagil James; Vivek Anand Menon; Mayur Parmar. Molecular Dynamics Simulation Study of Liquid-Assisted Laser Beam Machining Process. Volume 4: Processes 2018, 1 .

AMA Style

Sagil James, Vivek Anand Menon, Mayur Parmar. Molecular Dynamics Simulation Study of Liquid-Assisted Laser Beam Machining Process. Volume 4: Processes. 2018; ():1.

Chicago/Turabian Style

Sagil James; Vivek Anand Menon; Mayur Parmar. 2018. "Molecular Dynamics Simulation Study of Liquid-Assisted Laser Beam Machining Process." Volume 4: Processes , no. : 1.

Proceedings article
Published: 18 June 2018 in Volume 4: Processes
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Ultrasonic welding is a solid-state joining process which uses ultrasonic vibration to join materials at relatively low temperatures. Ultrasonic powder consolidation is a derivative of the ultrasonic additive process which consolidates powder material into a dense solid block without melting. During ultrasonic powder consolidation process, metal powder under a compressive load is subjected to transverse ultrasonic vibrations resulting in a fully-dense consolidated product. While ultrasonic powder consolidation is employed in a wide variety of applications, the effect of critical process parameters on the bonding process of powder particles during consolidation is not clearly understood. This study uses a coupled thermo-mechanical finite element analysis technique to investigate the effect of critical process parameters including vibrational amplitude and base temperature on the stress, strain, and particle temperature distribution during the ultrasonic powder consolidation process. The study finds that during this process, the ultrasonically vibrating tool imparts cyclic vibratory shear stress on the particles. The simulation also revealed that the particle temperature just reaches the recrystallization point. Higher vibration amplitude imparted higher frictional heat on the particles, thereby aiding the consolidation process. The simulation study also showed indications of thermal softening and restricted grain boundary sliding during the ultrasonic powder consolidation process. The outcomes of this study can be used to further the industrial applications of ultrasonic powder consolidation process as well as other ultrasonic welding based processes.

ACS Style

Sagil James; Shripal Bhavsar. Finite Element Analysis and Simulation of Ultrasonic Powder Consolidation Process. Volume 4: Processes 2018, 1 .

AMA Style

Sagil James, Shripal Bhavsar. Finite Element Analysis and Simulation of Ultrasonic Powder Consolidation Process. Volume 4: Processes. 2018; ():1.

Chicago/Turabian Style

Sagil James; Shripal Bhavsar. 2018. "Finite Element Analysis and Simulation of Ultrasonic Powder Consolidation Process." Volume 4: Processes , no. : 1.

Proceedings article
Published: 18 June 2018 in Volume 4: Processes
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Shape Memory Alloys are smart materials that tend to remember and return to its original shape when subjected to deformation. These materials find numerous applications in robotics, automotive and biomedical industries. Micromachining of SMAs is often a considerable challenge using conventional machining processes. Micro-Electrical Discharge Machining is a combination of thermal and electrical processes, which can machine any electrically conductive material at micron scale independent of its hardness. It employs dielectric medium such as hydrocarbon oils, deionized water, and kerosene. Using liquid dielectrics has adverse effects on the machined surface causing cracking, white layer deposition, and irregular surface finish. These limitations can be minimized by using a dry dielectric medium such as air or nitrogen gas. This research involves the experimental study of micromachining of Shape Memory Alloys using dry Micro-Electrical Discharge Machining process. The study considers the effect of critical process parameters including discharge voltage and discharge current on the material removal rate and the tool wear rate. A comparison study is performed between the Micro-Electrical Discharge Machining process with using the liquid as well as air as the dielectric medium. In this study, microcavities are successfully machined on shape memory alloys using dry Micro-Electrical Discharge Machining process. The study found that the dry Micro-Electrical Discharge Machining produces a comparatively better surface finish, has lower tool wear and lesser material removal rate compared to the process using the liquid as the dielectric medium. The results of this research could extend the industrial applications of Micro Electrical Discharge Machining processes.

ACS Style

Sagil James; Sharadkumar Kakadiya. Experimental Study of Machining of Shape Memory Alloys Using Dry Micro Electrical Discharge Machining Process. Volume 4: Processes 2018, 1 .

AMA Style

Sagil James, Sharadkumar Kakadiya. Experimental Study of Machining of Shape Memory Alloys Using Dry Micro Electrical Discharge Machining Process. Volume 4: Processes. 2018; ():1.

Chicago/Turabian Style

Sagil James; Sharadkumar Kakadiya. 2018. "Experimental Study of Machining of Shape Memory Alloys Using Dry Micro Electrical Discharge Machining Process." Volume 4: Processes , no. : 1.

Proceedings article
Published: 18 June 2018 in Volume 1: Additive Manufacturing; Bio and Sustainable Manufacturing
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Dye-Sensitized Solar Cells (DSSC) are third generation solar cells used as an alternative to c-Si solar cells. DSSC are mostly flexible, easier to handle and are less susceptible to damage compared to c-Si solar cells. Additionally, DSSC is an excellent choice for indoor application as they perform better under diverse light condition. Most DSSCs are made of liquid medium sandwiched between two conductive polymer layers. However, DSSCs have significantly lower efficiencies compared to silicon solar cells. Also, use of liquid medium resulting in leaking of liquid, and occasional freezing during cold weather, and thermal expansion during hot weather conditions. DSSC can be manufactured in small quantities using relatively inexpensive solution-phase techniques such as roll-to-roll processing and screen printing technology. However, scaling-up the DSSC manufacturing from small-scale laboratory tests to sizeable industrial production requires better and efficient manufacturing processes. This research studies the feasibility of using additive manufacturing technique to fabricate electrodes of DSSC. The study aims to overcome the limitations of DSSCs including preventing leakage and providing more customized design. Experimental studies are performed to evaluate the effects of critical process parameters affecting the quality of electrodes for DSSC. Volume resistivity test is performed to evaluate the efficiency of the electrodes. In this study, the electrodes of DSSC are successfully fabricated using Fused Disposition Modeling (FDM) 3D printing technique. The results of this study would enable additive manufacturing technology towards rapid commercialization of DSSC technology.

ACS Style

Sagil James; Rinkesh Contractor; Chris Veyna; Galen Jiang. Fabrication of Efficient Electrodes for Dye-Sensitized Solar Cells Using Additive Manufacturing. Volume 1: Additive Manufacturing; Bio and Sustainable Manufacturing 2018, 1 .

AMA Style

Sagil James, Rinkesh Contractor, Chris Veyna, Galen Jiang. Fabrication of Efficient Electrodes for Dye-Sensitized Solar Cells Using Additive Manufacturing. Volume 1: Additive Manufacturing; Bio and Sustainable Manufacturing. 2018; ():1.

Chicago/Turabian Style

Sagil James; Rinkesh Contractor; Chris Veyna; Galen Jiang. 2018. "Fabrication of Efficient Electrodes for Dye-Sensitized Solar Cells Using Additive Manufacturing." Volume 1: Additive Manufacturing; Bio and Sustainable Manufacturing , no. : 1.

Proceedings article
Published: 18 June 2018 in Volume 4: Processes
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Smart materials are new generation materials which possess great properties to mend themselves with a change in environment. Smart materials find applications in a wide range of industries including biomedical, aerospace, defense and energy sector and so on. These materials possess unique properties including high hardness, high strength, high melting point and low creep behavior. Manufacturing of these materials is a huge challenge, particularly at the micron scale. Abrasive waterjet micromachining (AWJMM) is a non-traditional material removal process which has the capability of machining extremely hard and brittle materials such as glasses and ceramics. AWJMM process is usually performed with nozzle and workpiece placed in air. However, machining in the air causes spreading of the waterjet resulting in low machining quality. Performing the AWJMM process with a submerged nozzle and workpiece could eliminate this problem and also reduce noise, splash, and airborne debris particles during the machining process. This research investigates Submerged Abrasive Waterjet Machining (SAWJMM) process for micromachining smart ceramic materials. The research involves experimental study on micromachining of smart materials using an in-house fabricated SAWJMM setup. The effect of critical parameters including stand-off distance, abrasive grain size and material properties on the cavity size, kerf angle and MRR during SAWJMM and AWJMM processes are studied. The study found that SAWJMM process is capable of successfully machining smart materials including shape memory alloys and piezoelectric materials at the micron scale. The machined surfaced are free of thermal stresses and did not show any cracking around the edges. The critical process parameter study revealed that stand-off distance and abrasive grit size significantly affect the machining results.

ACS Style

Sagil James; Anurag Mahajan. Experimental Study of Machining of Smart Materials Using Submerged Abrasive Waterjet Micromachining Process. Volume 4: Processes 2018, 1 .

AMA Style

Sagil James, Anurag Mahajan. Experimental Study of Machining of Smart Materials Using Submerged Abrasive Waterjet Micromachining Process. Volume 4: Processes. 2018; ():1.

Chicago/Turabian Style

Sagil James; Anurag Mahajan. 2018. "Experimental Study of Machining of Smart Materials Using Submerged Abrasive Waterjet Micromachining Process." Volume 4: Processes , no. : 1.

Journal article
Published: 01 June 2018 in Journal of Manufacturing Processes
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Cold Spray (CS) process is a deposition process in which micron-to-nano sized solid particles are deposited on a substrate using high-velocity impacts. Unlike thermal spray processes, CS process does not melt the particles thus retaining their original physical and chemical properties. These characteristics make CS process ideal for various engineering applications. The bonding mechanism involved in CS process is hugely complicated considering the dynamic nature of the process. Even though CS process offers great promises, the realization of its full potential is limited by lack of understanding of the complex mechanisms involved. The study focuses on understanding the complex nanoscale mechanisms involved in CS process. The study uses Molecular Dynamics (MD) simulation technique to understand the material deposition phenomenon during the CS process. For the simulation conditions used, the study finds that the quality of deposition is highest for an impact velocity of 700 m/s, the particle size of 20 Å and an impact angle of 90°. The von Mises stress and plastic strain analysis revealed that bonding mechanism in CS process could be attributed to adiabatic softening, adiabatic shear instabilities followed by interfacial jetting of particle materials resulting in a uniform coating. The findings of this study can further the scope and applications of CS process.

ACS Style

Aneesh Joshi; Sagil James. Molecular dynamics simulation study of cold spray process. Journal of Manufacturing Processes 2018, 33, 136 -143.

AMA Style

Aneesh Joshi, Sagil James. Molecular dynamics simulation study of cold spray process. Journal of Manufacturing Processes. 2018; 33 ():136-143.

Chicago/Turabian Style

Aneesh Joshi; Sagil James. 2018. "Molecular dynamics simulation study of cold spray process." Journal of Manufacturing Processes 33, no. : 136-143.