1. Additive manufacturing using twin wire GMAW: Now a days, additive manufacturing (AM) has become more accessible, and the areas of potential use have expanded in all dimension of manufacturing, nonmetallic to metallic, micro to bulk, and simple to complex component. Wire arc additive manufacturing (WAAM) is a variant of AM where wire is fed to produce weld bead and form a layer. WAAM Process is basically used to fabricate the bulk component where gas metal arc welding (GMAW) is widely used as heat source. The use of twin wire GMAW as heat source in WAAM process will increase the production rate in manufacturing of large component. The Shape and size of weld bead play a crucial role in path planning, and overlapping of bead to maintain a fair surface condition WAAM process. My research investigations incorporated weld bead analysis and fabrication large component. The result of this investigation further may be incorporated in the industry for shop floor production of customized component.
  2. Automated Welding: Welding is one of the most important and sought after material joining methods in manufacturing industries. The trend is to achieve more and more degree of automation in the welding processes. Being a process of several complexities, the welding poses many challenges to the researcher. Our study is a comprehensive one in nature comprising of stress relieving through vibration, minimising the human intervention and associated errors by using robotic welding set-up, developing heat source models and analysis of micro structural changes in weldments. We plan to explore in the domain of multi-wire and multi-pass welding with maximum amount of automation incorporated. The study also covers the Quality Assurance in welding and current practices in inspection of welded components, and welding defects.
  3. Design for Additive Manufacturing: The research includes modeling, design and fabrication of structural parts for additive manufacturing (AM). This also includes the structural topology optimization for Additive Manufacturing by considering the AM constraints like support structures, minimum feature resolution, material continuity, anisotropic, tool path etc. which provides the basic framework to integrate the manufacturability into structural topology optimization for the AM process to achieve more strength to weight ratio. This research also includes the design and fabrication of the heterogeneous object using 3D printing which can be used in various fields like biomedical, prosthetic and orthopedic etc.
  4. Dynamic analysis of bolted joints: Failure of bolted joints in structures like bridges, buildings, aircrafts etc. can lead to a disaster. It costs life as well as money. Failure of bolted joint is mainly attributed to axial bolt preload loss of bolted joint. So, health monitoring of bolted joint is of utmost importance. There are various methods for health monitoring of bolted joint. Most effective of all of them is use of piezo-electric patches. Piezo-electric patches are used to detect bolt preload loss. This method principally depends upon change in nonlinear characteristics parameter of bolted joint with change in axial preload. So, this work focuses on fabrication and dynamic analysis of smart bolt using shape memory alloys. These smart bolts are capable of regaining its lost preload once detected.
  5. Electric Pulse Aided Plastic Deformation: Application of electric pulses during deformation will accelerate the motion of dislocations by transfer of momentum from electrons to dislocations thus making plastic deformation of materials easy. This effect is known as “Electroplastic effect”. Electric Pulse Aided Plastic Deformation (EPAD) is also known as “Electrically Assisted Manufacturing” (EAM). EAM is an innovative manufacturing technique which is used to process difficult to process materials such as Advanced High Strength Steels (AHSS). Advantages of passing electric current during deformation includes: Reduction of flow stresses, Reduction of spring back (which is the major problem when forming high strength materials) and enhancement of formability. Application of high density electric pulses for very short duration during deformation will result in unique microstructural changes recrystallization at lower temperatures compare to conventional heat treatment, formation of nanostructure phases and Dynamic Recrystallization (DRX). EAM can be best alternative for Hot Forming which involves heating bulk of the material in furnace and formation of oxidation layers between dies and workpiece
  6. Experimental and Numerical Investigations in AC square Waveform Welding: This work is based on the waveform control in welding. The present fabrication industry uses square waveform power source to obtain better quality products in terms of strength, ductility and hardenability. In addition to that the merit of the power source is that the bead deposition is regular instead of producing wire stubbing and wire dripping kinds of deposition. The study compares the quality of weld deposition with the conventional power sources.
  7. Functionally Gradient Materials through Weld-Deposition: Functionally Gradient Materials (FGM) may have a controlled variation of the material matrix so as to obtain the desired distribution of the properties such as color, density, porosity, hardness, toughness etc. The objects built through Additive Manufacturing techniques are inhomogeneous or non-uniform, i.e., they are inherently anisotropic. When this inherent nature is carefully exploited, the anisotropy transforms into the desired distribution of the properties. Weld-deposition based Additive Manufacturing techniques offer unique advantages on that front due to their ability to control the properties of the deposited matrix through the control of process parameters like current, layer thickness etc. The present work focuses on obtaining a wide range of material properties by selecting filler wires with different properties and controlling the deposition rate of each of them separately.
  8. Incremental Sheet Forming (ISF): Incremental Sheet Forming is a flexible process, in which a flat sheet is deformed to desired geometry by series of localized deformations. Incremental sheet forming is capable of forming complex three dimensional parts using simple tools. It is characterized by high formability, low forming forces, component independent tooling and low cost manufacturing of customized/low volume products Double sided incremental forming (DSIF) is the most flexible variant of incremental sheet forming that can form complex geometries with good accuracy. It uses two independently controlled tools, one on either side of sheet, to form the geometry. At any instant, one tool will be forming the geometry while the other provides local support. Role of tools (forming or supporting) can be interchanged to form features on both sides of sheet and/or multiple features in single setup
  9. Integrated Metal Additive and Formative Manufacturing System: In this work an Integrated Metal Additive manufacturing and Forming System, which combines a forming operation with wire arc additive manufacturing (WAAM) is to be developed. Combining a forming operation with WAAM results into certain advantages like the flatness of the top surfaces will be improved from middle-convex to nearly plane and the appearance of side faces also gets improved; i.e. overall forming appearance of the deposited component will be enhanced, the residual stress can be reduced under a certain pressure, the forming operation also decompose the coarse grains into fine grains, eliminating cracking and deformation. Complex shapes and geometries are also possible to be manufactured to some extent by intermittent forming operation during the weld deposition in WAAM. Development of slicing and path planning techniques for the realization of large overhang features in WAAM. Integration of forming tools with the wire-arc deposition system. Characterization studies of the hybrid formed components to assess the influence on material properties. Modeling and Finite Element Analyses of the developed integrated system
  10. Micro Injection Molding: Demand for micro components has been increasing considerably in the recent years due to the advances in areas of micro fluidics, biotechnology, optical data communication, MEMS, NEMS etc. Micro components are mainly produced using plastics due to the relative ease of manufacturing. Injection Molding (IM) is one of the widely used processes for producing plastic components. However, Injection Molding technology cannot be used directly to produce micro - components as plastics behave differently when they flow through micro channels. The technology of micro injection molding (µIM) has emerged by considering these rheological effects when the fluid flows through micro channels. Research in the area of µIM is in developing phase. Even now, successful replication of micro - features is quite a task in µIM. It would be even more challenging when micro features are be replicated with out compromising much on the mechanical properties of the product. So, in this project we are making an attempt to produce the micro parts while improving the mechanical properties of the same.
  11. Morphological and Mechanical Behavior of Additive Manufactured Low Carbon Alloy Thin Wall Components: Study the effect of consistent inter-pass temperature in fabrication of thin wall geometries. Study about microstructure evaluation. Simulation studies and their validation through experimental results. Mechanical behavior of the deposited thin walls. To correlate the mechanical and morphological behaviors.
  12. Rapid Prototyping & Manufacturing: Rapid Prototyping (RP), also known as Layered Manufacturing (LM), is a totally automatic process of manufacturing objects directly from their Computer Aided Designing (CAD) models. By using RP technology 3D models can be easily generated by layer by layer deposition process. In this process 3D objects are sliced into 2D layers, where it makes simple to construct a 3D model and ease of manufacture. The prototype is developed from the bottom of the base, thus a layer by layer deposition can be done, further the model is developed and it is cured or post processed.
  13. Sustainable machining process: Manufacturing industries are facing great challenges in developing an environmental friendly sustainable machining process. The strict rules framed by the organization like International Organization for Standardization (ISO) and Occupational Health and Safety Advisory Services (OHSAS) have made the industries and researchers to work in the direction of developing an environmental friendly sustainable machining process. The theme of sustainable machining process lies in the development of a process which will maximize the product quality without compromising on the environmental issues. This can be achieved by reducing the consumption of hazardous substances which are used in machining process. Some ways of achieving this goal is to reduce the use of cutting fluids, using environmental friendly cutting fluids, maximizing the cutting tool efficiency and by reducing the consumption of energy during cutting process.
  14. Voxels-based modeling of the AM process for thermal management: The physical AM process involves heat and mass transfer including, which results in a complex thermal history .Experimental measurements of the temperature are considered to be difficult because of the localized heating and superfast melting and solidification involved. Thermal history of the entire process can be studied and thermal behavior of the process can be analyzed using the numerical models.“ Voxel” is a 3 dimensional element analogous to “pixel” in 2D. In volumetric modeling an object is represented as a collection of voxels in 3D arrangement which may be regular or irregular. The main advantages of this type of representation is it is simple, intuitive, unambiguous and unique representation. MATLAB is used as a tool for analyzing various heat and temperature at a voxel.