Dr. Anand Joshi - G.H Patel College of engineering & technology (original) (raw)

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Papers by Dr. Anand Joshi

Heliyon, 2019

The advancement in the field of material science has gifted us new electrically conductive materi... more The advancement in the field of material science has gifted us new electrically conductive materials having good mechanical properties and thermal characteristics. Machining these materials using conventional machining process is a challenging task. Electrical discharge machining (EDM) is a well-established machining process used to manufacture process hard materials having geometrically complex shapes, that are extremely difficult to machine traditionally. EDM is a thermo-electric process in which material is eroded by rapidly recurring sparks between the non-contacted electrode and workpiece. As there is no direct contact between the electrodes in EDM, machining defects like mechanical stresses, clattering & vibration do not create problems during machining. In spite of the advantages of the process, its use in industry is limited owing to poor surface finish and low volumetric material removal. To overcome these drawbacks, the metallic powder is mixed in the dielectric fluid, which increases its conductive strength and increases the spark gap distance between the tool and workpiece. This new evolved material removal process is called Powder Mixed Electrical Discharge Machining (PMEDM). The added powder significantly affects the performance of the EDM process. The objective of this review is to benefit the researchers to understand the PMEDM concept precisely and study the process parameters furthermore in particulars to get enhancements in the process to achieve better quality levels.

Effect of Powder Concentration in EDM Process with Powder-Mixed Dielectric (PMD-EDM)

Applied Mechanics and Materials, 2015

Ti–6Al–4V is widely used in the aerospace, automobile, and biomedical fields, but is a difficult ... more Ti–6Al–4V is widely used in the aerospace, automobile, and biomedical fields, but is a difficult to machine material. Electrical discharge machining (EDM) is regarded as one of the most effective approaches to machining Ti–6Al–4V alloy, since it is a noncontact electro-thermal machining method, and it is independent from the mechanical properties of the processed material. In electro discharge machining (EDM), dielectric plays an important role during machining operation. The machining characteristics are greatly influenced by the nature of dielectric used during EDM machining. In present paper silicon powder suspended kerosene as dielectric is used to explore the influence of these dielectrics on the performance criteria such as material removal rate (MRR), tool wear rate (TWR) and surface roughness (Ra) during machining of titanium alloy (Ti-6Al-4V). Peak current, pulse on time, pulse off time and concentration of powders added into dielectric fluid of EDM were chosen as process p...

Experimental Research on Performance of Electrochemical Machining Process on Hard Material (Carbon Steel EN9) and Soft Material (Copper)

Applied Mechanics and Materials, 2014

Electrochemical Machining is one of established non-traditional machining process which is widely... more Electrochemical Machining is one of established non-traditional machining process which is widely used in micro machining parts. Purpose of this research paper is to investigate effect of Electrochemical Machining under low voltage and relatively high current rating on concentrated or masked work piece of Copper and Carbon Steel EN9. Developing Machine set up with the help of PLC and SCADA device for Accurate Positioning and reliable data supervising which includes ECM, basic working principle of ECM, selection and development of components, implementation and to analyze the effect of change in the parameters of the process. Selection and development part will cover design of frame, fixture, pump, filter, tool, electrolyte, and work piece material as a mechanical part, selection of electric drive system and PLC. PLC programming and hardware circuit as electrical and programming part.

Zeptogram Scale Mass Sensing using Single Walled Carbon Nanotube Based Bio Sensors

Sensors and Actuators A: Physical, Jan 1, 2011

During recent years carbon nanotubes are being increasingly used for mass sensing. This study inv... more During recent years carbon nanotubes are being increasingly used for mass sensing. This study investigates single walled carbon nanotubes as the sensing devices for biological objects. An expression has been formulated to detect the mass of biological objects from the shift of frequency. The application of a carbon nanotube for zeptogram-level mass detection has been explored. Molecular structural mechanics approach has been used for investigating the dynamic responses of chiral single walled carbon nanotube based nano biosensors. The nanotube is considered as a space frame structure. The beam element properties are calculated by considering mechanical characteristics of covalent bonds between the carbon atoms in the hexagonal lattice. The mass of each beam element is assumed as point masses at nodes coinciding with carbon atoms. The results suggest that a single walled carbon nanotube is a promising candidate for a bio-molecular nano sensor with the sensitivity reaching to an order of 0.12 Zg/GHz.

vibration signature analysis of single walled carbon nanotube based nano mechanical sensors

In the present paper, the simulation of the mechanical responses of individual carbon nanotubes t... more In the present paper, the simulation of the mechanical responses of individual carbon nanotubes treated as thin shells with thickness has been done using FEM. The resonant frequencies of the fixed free and the bridged SWCNT have been investigated. This analysis explores the resonant frequency shift of SWCNTs caused by the changes in the size of CNT in terms of length as well as the masses. The results showed the sensitivity of the single walled carbon nanotubes to different masses and different lengths. The results indicate that the mass sensitivity of carbon nanotube nanobalances can reach 10−21 g and the mass sensitivity increases when smaller size nanotube resonators are used in mass sensors. The vibration signature exhibits super-harmonic and sub-harmonic response with different level of mass. In order to explore the suitability of the SWCNT as a mass detector device, the simulation results of the resonant frequency of fixed free SWCNT are compared to the published experimental data. It is shown that the FEM simulation results are in good agreement with the experimental data and hence the current modelling approach is suitable as a coupled-field design tool for the development of SWCNT-based NEMS applications.

The effect of pinhole defect on vibrational characteristics of single walled carbon nanotube

Carbon nanotubes are widely used in the design of nano sensors and actuators. Any defect in the m... more Carbon nanotubes are widely used in the design of nano sensors and actuators. Any defect in the manufactured nanotube affects its sensing performance and also influences its dynamic behavior. In this paper, the effect of pinhole defects on the dynamic characteristics of carbon nanotubes is investigated using continuum mechanics and the molecular structural mechanics approach. Dynamic analysis is performed for achiral nanotubes using the continuum mechanics approach with cantilever boundary condition, while for chiral nanotubes the molecular structural mechanics method is used. The shift of the principal frequency of the nanotube with number of pinhole defects on the length is observed and analyzed. The simulation results indicate that the existence of defects mostly affects the resonant frequency (bending rigidity) of single walled carbon nanotubes as the number of defects (pinhole) increase. Further, it is also observed that with the reduction in tube length, the variations in resonant frequency are enhanced. However, it is found that the frequency variation is less sensitive to the nanotube diameter.► Dynamic analysis of achiral and chiral nanotubes with pinhole defect is performed. ► Shift of the principal frequency of the nanotube with number of pinhole defects is analyzed. ► Existence of multiple defects affects the resonant frequency of carbon nanotubes. ► Reduction in nanotube length enhances the variations in resonant frequency. ► Frequency variation is less sensitive to the nanotube diameter.

Vibration Response Analysis of Doubly Clamped Single Walled Wavy Carbon Nanotube Based Nanomechanical Sensors

Effect of chirality and atomic vacancies on dynamics of nanoresonators based on SWCNT

An Investigation of Mass Sensitivity of Fixed Free Single Walled Carbon Nanotube Based Nano Mechanical Sensors

Journal of Nanotechnology in …, Jan 1, 2010

Fracture mechanics at the nanoscale level is a very complex phenomenon, whereas the macroscale fr... more Fracture mechanics at the nanoscale level is a very complex phenomenon, whereas the macroscale fracture mechanics approach can be employed for nanoscale to simulate the effect of fracture in single-walled carbon nanotubes (SWCNTs). In this study, an extended finite element method is used to simulate crack propagation in carbon nanotubes. The concept of the model is based on the assumption that carbon nanotubes, when loaded, behave like space frame structures. The nanostructure is analyzed using the finite element method, and the modified Morse interatomic potential is used to simulate the nonlinear force field of the C-C bonds. The model has been applied to single-walled zigzag, armchair, and chiral nanotubes subjected to axial tension. The contour integral method is used for the calculation of the J-integral and stress intensity factors (SIFs) at various crack locations and dimensions of nanotubes under tensile loading. A comparative study of results shows the behavior of cracks in carbon nanotubes. It is observed that for the smaller length of nanotube, as the diameter increased, the stress intensity factor is linearly varied while for the longer nanotube, the variation in stress intensity factor is nonlinear. It is also observed that as the crack is oriented closer to the loading end, the stress intensity factor shows higher sensitivity to smaller lengths, which indicates more chances for crack propagation and carbon nanotube breakage. The SIF is found to vary nonlinearly with the diameter of the SWCNT. Also, it is found that the predicted crack evolution, failure stresses, and failure strains of the nanotubes correlate very well with molecular mechanics simulations from literature.