Mechanical Engineering

The main purpose of this study is to analysis the thermomechanical behavior of the dry contact between the brake disc and pads during the braking phase. The thermal-structural analysis is then used coupling to determine the deformation and the Von Mises stress established in the disc, the contact pressure distribution in pads. The results are satisfactory when compared with those of the specialized literature.

Visco- Elastic Plates are being increasingly used in the aeronautical and aerospace industry as well as in other fields of modern technology. To use them a good understanding of their structural and dynamical behavior is needed. In the modern technology, the plates of variable thickness are widely used in engineering applications. The present work is to develop for the use of research workers in space technology, mechanical sciences and nuclear energy where certain components of the structure have to operate under the elevated temperature. The aim of present paper is to study the bi-linearly thermal effect on vibration of visco-elastic square plate whose thickness varies parabolically in x-direction. A frequency equation is derived by using Rayleigh-Ritz technique. Two modes of frequency are calculated by the latest computational software for the various values of taper parameter and thermal gradient.

Epoxy/Unsaturated polyester (UP) blend is prepared with varying montmorillonite (MMT) clay (viz. 0%, 1%, 2%, 3%, 4% and 5% by weight) content. The chemical resistance of these nanocomposites to some acids, alkalis and solvents is studied. The hardness property of these nanocomposites is determined. The nanocomposites showed good resistance to acids and alkalis, but showed minimal resistance to solvents. The nanocomposite blend indicated better hardness at 3% clay when compared to other combinations considered in this study. The homogeneous morphologies of the UP toughened epoxy and epoxy/UP/clay nanocomposite systems are ascertained using scanning electron microscope (SEM) and transmission electron microscope (TEM) studies. The above studies indicate that the Epoxy/UP/MMT clay nanocomposite can be used in applications like aerospace, automobiles and marine systems. The main objective of the study is to identify a low-cost, light-weight, eco-friendly and high-strength composite material that can be used for various engineering and commercial applications.

The rapid growth in the energy consumption at individual level has given rise to a dramatic increase in both air and water pollution problems. The automobile is probably the most notorious source of atmospheric air pollution on a total mass basis. Under the Indian Conditions two and four wheelers have become the most popular mode of transport. In the present work catalytic converter was chosen for SI engine emission control, to reduce CO, HC and NOx emission. A catalytic converter has to be designed and introduced in the exhaust line of the SI engine. In the present work Maruthi omni engine is chosen for emission control study using an electrically heated catalytic converter. The objective of the electrically heated catalytic converter is to reduce the cold start emission of CO, HC and NOx in the exhaust gas of the engine. The catalytic converter is made of stainless steel plate. The plate is coated with copper, Nickel and Chromium catalytic materials. These emission levels will be measured using the AVL exhaust gas analyzer and the results will be analyzed.

This paper describes an approach for formulation of approximate, generalized field data based mathematical model (FDBM) for the process of PVC pipe manufacturing at some industries. The present work is aimed at establishing mathematical relationship between the responses and inputs at the operation of PVC pipe manufacturing process using single screw extruder. For this purpose various small scale PVC pipes manufacturing industries are visited. The operation of PVC pipe extrusion is studied. The study is focused on an extrusion line starting from its electric motor, extruder hopper, barrel, extruder screw up to the extruder die. First of all the various dependent variables in form of responses and the independent variables in the form of inputs are decided. The categorization of these variables are made in terms of pi terms viz. ?1 ?2 ?3 as independent and ?D1, ?D2, ?D3, ?D4 as dependent variables. Then the field observations are taken and accordingly data collection process is completed. After this step, an approximate, generalized field data based mathematical models are developed. This work presents an approach to check the reliability of models, which is executed by comparing error frequency graphs of various mathematical models formed. After that the influence of the various independent pi terms in the models are studied by analyzing the indices of the various pi terms. Through the technique of sensitivity analysis, the change in the value of a dependent pi term caused due to an introduced change in the value of independent individual pi term is evaluated. The ultimate objective of this work is not merely developing the mathematical models but to find out the best set of independent variables, which will result in maximization or minimization of the objective functions. This is achieved by applying the technique of optimization. Thus the objects of these models are tested to optimize the inputs required for satisfying the various responses. The comparative analysis is made of the outputs of the network with observed data and the data calculated from the mathematical models. This modeling and simulation approach enables entrepreneur of small scale PVC pipes manufacturing industries to get system wide view obtained by deliberately making local changes in their manufacturing system. They can predict its impact on performance of their machines. With the help of the models, one can find a method to improve the productivity of the industry. The results obtained from experiments are also analyzed by the development of different polynomial mathematical models and its related graphs. Recommendations with respect to improvement in the current operation are suggested and future changes are proposed.

Some physical properties of the rough rice were studied at 10.29, 15.37, 20.5, 25.4, and 30.6% d.b. moisture contents. The length, width, thickness, equivalent diameter, and sphericity increased linearly from 10.63 to 10.82 mm, 1.96 to 2.14 mm, 1.82 to 1.99 mm, 3.34 to 3.55 mm, and 31.52 to 33.24%, respectively, as moisture content increased from 10.29 to 30.6% d.b. In the same moisture range, the one-thousand grain mass, grain volume, surface area, and angle of repose increased linearly from 21.34 to 25.04 g, 20.62 to 24.16 mm3, 34.45 to 38.36 mm2, and 28.54º to 39.41 º, respectively. Results showed that the bulk density, true density, and porosity increased linearly from 480.32 to 499.12 kg/m3, 945.71 to 1131.02 kg/m3, and 49.21 to 55.87%, respectively, with increasing moisture content. The static coefficient of friction varied from 0.479 to 0.732 over different structural surfaces in the specified moisture content range. The specific heat capacity varied from 1654 to 2517 J/kg K in 50, 60, 70, and 100 ºC particles temperatures and for the specified moisture content levels.

In the present work, an effort has been made to investigate the effect of welding parameters on bead geometry. Mathematical models were developed by using 2- level half factorial technique to predict the bead geometry within the range of control parameters or operating variables for single wire submerged are welding. The models developed can be employed easily in automatic or robotic welding, in the form of program, for obtaining the desired high quality welds. Current, open circuit voltage, welding speed and nozzle-to-plate distance were taken as welding variables constant. The models were developed from the observed values, with the help of design matrix.  It was found that penetration increases significantly with current, decreases with welding speed and remains unaffected by open circuit voltage & nozzle to plate distance. Reinforcement was found to increase with current and decrease with open circuit voltage, welding speed and there is no effect by nozzle to plate distance. Weld bead width was found to increase with open circuit voltage, decrease with welding speed; but ‘w’ increases with increase in nozzle to plate distance. The adequacies of the models were tested by use of analysis of variance technique and signification of coefficients was tested by student’s-test’. The combined and main effect of different parameters involved has been presented in graphical form.

Any process involving the process of increasing the efficiency of any mechanical part is a vital concept in the field of engineering and technology and equally vital in the field of energy and power systems too. This paper is based on a technique that could be used to improvise and increase the efficiency of the gas turbine aviation engines which was theoretically stated after conducting series of experiments and analysis through software. This technique could be called as REPOLARIZED MAGNETIC ROTATION technique which converts the magnetic power to mechanical power which could therefore be used to compress air in compressor, and thereby increase the efficiency of the gas turbine engines used in aviation. Various techniques adapted to design, analyze and fabricate the test engine were stated in this paper.

In this work, an experimental study to obtain the fatigue endurance limit for an aluminum alloy7075-T651 were carried out at stress ratio R=-1 and rotary bending tests. The fatigue tests were performed at RT and 250 °C in order to establish the S–N curve equations. The fatigue endurance limits for the alloy at different temperature conditions were calculated at 107 cycles from the empirical S-N curve equations. It was found that the fatigue endurance limit decrease with increasing the temperature. Also The effect of shot peening on the rotating bending fatigue behavior of 7075-T651 was studied. The fatigue strength of specimens tested at250oC at 107cycles is reduced about 12%. The fatigue strength of specimens tested at250oC prior to (10 min.) SP at 107cycles is increased by 7.2%. The roughness of the samples increases after shot peening which leads to the deterioration of the fatigue strength, because the surface of the samples become prone to nucleation of cracks.

The Navier–Stokes equations, named after Claude-Louis Navier and George Gabriel Stokes, describe the motion of fluid substances. These equations arise from applying Newton's second law to fluid motion, together with the assumption that the stress in the fluid is the sum of a diffusing viscous term (proportional to the gradient of velocity) and a pressure term. For solving a free surface flow problem, the basic governing equations are Navier Stokes equations (N-S equations). Hence the study of methods, used for solving N-S equations is important. There are various methods to solve the N-S equations. The equations are useful as they describe the physics of many things of scientific and engineering interest. The Navier–Stokes equations are also of great interest in a purely mathematical sense.