Applied Mechanics and Materials Vols. 110-116

Abstract: For mass production, mainly automation is used, in which cutting parameters are set to obtain required surface roughness. The parts like IC Engine piston, cylinders require very smooth surface finish. The same is the case of sleeves, collets etc., of machine parts. These are made by automatic machining operations. To get approximate value of required surface roughness, the cutting parameters that are to be set with help of Adaptive Neuro Fuzzy Inference System (ANFIS) that is designed by using Fuzzy Logic Toolbox. The Fuzzy Logic Toolbox is a collection of functions built on the MATLAB numeric computing environment. It provides tools to create and edit fuzzy inference systems (FIS) within the framework of MATLAB. ANFIS constructs a relation between given parameters (input data and output data), when it is trained with experimentally predetermined values. It consists of different functions, of which bell and triangular membership functions are used for our purpose. The comparison of accuracy of predicted values for both membership functions are performed using testing data. The training and testing data was obtained performing operation on CNC lathe for 50 work pieces of which 40 were used for training ANFIS and the remaining 10 were used for comparing the accuracy of both Bell and Triangular membership functions. The detailed analysis and procedure is presented.

Abstract: — High speed machine tool is one of the basic needs in catering to a wide range of machining parameters with tight tolerance band. In high speed machine tool many key factors like geometric, cutting force and thermal errors decides the performance of the machine. However amongst these three, error due to thermal deformation is an important factor in influencing the accuracy level of component produced. A survey amongst Indian machine tool manufacturers reveals that there is a strong need to infuse recent technological developments in thermal error prediction and derive methodologies to minimize the same in high speed machine tool. This paper attempts snapshots of a review relating to the errors causing thermal deformations and the modeling techniques developed by researchers and practitioners globally in present scenario. The conclusions made at the end of this paper may not give the full solutions to the problems relating to thermal error but, gives a broad perspective for the Indian machine tool manufacturers’, practitioners as well researchers in India to look in to the research relating to thermal error modeling, analysis and corrective measures.

Abstract: — This paper presents an experimental investigation on the influence of cutting parameters of wire cut Electrical Discharge Machining (Wire-EDM) during the machining of tungsten carbide and optimization of machining parameters on kerf width. The investigation was conducted by considering the varying parameter of average machining voltage, spark on time, spark off time, and capacitance with Taguchi method as optimizing technique. L₉ orthogonal array has been used to determine the S/N ratio, analysis of variance and ‘F’ test values for indicating most significant parameter affecting the machining performance. The significant factors average machining voltage for kerf width. Spark on time, spark off time and capacitance are obtained as insignificant parameters. Further verification of improvements in the quality characteristics has been made through conformation test to the chosen initial parameter setting. The optimal combination of WEDM parameters satisfies the real requirement of quality machining of tungsten carbide.

Abstract: — Parametric optimization of electric discharge machining (EDM) is a challenging task. Many researchers have employed different multi-objective optimization techniques for the same. This work employs multi-response signal-to-noise (MRSN) technique to find the optimum factor/level combination of input parameters. Experiments have been conducted on die-sinking EDM by taking heat treated D2 steel as work piece and copper as tool electrode. Experiments have been designed as per Taguchi’s L36 orthogonal array. Two cases v.i.z. high cutting efficiency and high surface finish have been taken. Analysis of variance (ANOVA) is employed to indicate the level of significance of machining parameters in both the cases. Finally, results have been verified experimentally and a significant improvement in material removal rate and surface roughness is observed.

Abstract: Effect of internal heat source on the onset of convection in nanofluid layer heated from below is studied. The lower boundary and upper boundary are assumed to be rigid and free respectively. The two important effects namely the Brownian motion and thermophoresis have been included in the model of nanofluid. Linear stability analysis has been made to investigate the effect of internal heat source on the onset of convection. Galerkin method is used to obtain the analytical expression for Rayleigh number in the non-oscillatory mode and result are depicted graphically. It has been shown that the internal heat source, nanoparticle Rayleigh number and modified diffusivity ratio have a destabilizing effect depending upon the values of various nanofluid parameters.

Abstract: The experimental study is conducted to determine the fluidization behavior and heat transfer variations across the bed in the bubbling fluidized bed having very fine particles. The powder is analyzed using scanning electron microscope (SEM) and Mastersizer analyzer. The bubbling fluidized bed set-up was designed, developed and installed for the hydrodynamic and heat transfer studies. From the experiments, it is found that the alumina powder with particle size range of 200nm to 10μm has agglomerate bubbling fluidized bed (ABF).

Abstract: As our knowledge about Nano grows we can apply Nano Technology in all fields of Science and Engineering. Molecular simulation can be used to simulate the manufacturing process in nano scale. In this paper, simulations in nano scale were investigated in two main reasons: 1- Morphology in Nano-Micro, 2-Simulation based on molecular dynamics. The basic and main aspects of both methods were explored and also a Matlab algorithm will be suggested to modeling the structure and dynamic in nano scale. First, some pieces in cylindrical and cubic forms were simulated and the effects of thermal treatment in different temperatures were investigated in light of this simulation. Second, a model based on molecular dynamics in 2D was developed to find out the effects of force exerted to AFM..

Abstract: The additive (3wt%) nano-particles of anatase-TiO₂ and monoclinic-ZrO₂ were prepared using ball-milling method to form Al₂O₃/3wt%TiO₂ and Al₂O₃/3wt%ZrO₂ nanocomposite powders. The incorporation of nano-particles can significantly enhance the microstructure and mechanic properties of Al₂O₃-base coating. The phase of microstructure coating was present mostly of γ-Al₂O₃ and α-Al₂O₃ phases, while anatase-TiO₂ was transformed to rutile-TiO₂ and monoclinic-ZrO₂ was changed to tetragonal-ZrO₂ due to such high temperature of plasma plume. SEM microstructures of the coatings mainly displayed a lamellar structure of Al₂O₃ with interlarmellar pores and well dispersed splats of TiO₂ and ZrO₂ phases. The Al₂O₃/3wt%ZrO₂ presented the lowest value of friction coefficient and sliding wear rate. It was found that the plasma-sprayed composite coating possessed better wear resistance than that of monolithic Al₂O₃ coating. The addition of nano-particles was found to improve friction coefficient and sliding wear resistance.

Abstract: Aluminum silicon carbide Metal Matrix Composites (Al-MMC) are widely used in aeronautical and automobile industries due to their excellent mechanical and physical properties. However the harder reinforcement particles make machining difficult. Tool wear occurs more quickly and reduces the life of the tool. This paper presents the experimental investigation on turning A356 matrix metal reinforced with 20 % by weight of Silicon carbide (SiC) particles, fabricated in house by stir casting. Fabricated samples were turned on medium duty lathe with Poly crystalline Diamond (PCD) inserts of 1300 and 1500 grade exposed to various cutting conditions. Parameters such as power consumed by main spindle, machined surface roughness and tool wear are studied. Scanning Electron Microscope (SEM) images support the result. It is evident that, surface finish, and power consumed are good for 1500 grade when compared with 1300 grade at higher cutting speed and tool wear is strongly dependent on the abrasive hard reinforcement particles.

Abstract: The molecular vibrations of 1-Naphtol were investigated in polycrystalline sample, at room temperature, by FT- IR and FT-Raman spectroscopy. In parallel, ab initio and various density functional (DFT) methods were used to determine the geometrical, energetic and vibrational characteristics of 1-Naphtol . On the basis of B3LYP/6-31G* and B3LYP/6-311+G** methods and basis set combinations, a xnormal mode analysis was performed to assign the various fundamental frequencies according to the total energy distribution (TED). The vibrational spectra were interpreted, with the aid of normal coordinate analysis based on a scaled quantum mechanical force field. The Infrared and Raman spectra were also predicted from the calculated intensities. Comparison of simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes. Simulation of Infrared and Raman spectra, utilizing the results of these calculations led to excellent overall agreement with observed spectral patterns. The investigation is performed using quantum chemical calculations conducted by means of the Gaussian 98W and Guassview set of programs. Further, density functional theory (DFT) combined with quantum chemical calculations to determine the first-order hyperpolarizability.