Abstract

The main objective of this paper is to compare Regression Method with Artificial Neural Network Method in prediction of surface roughness in creep feed grinding. Data used in this paper has been extracted from creep feed grinding of a cobalt based superalloy (MAR-M-509) turbine blade. The input parameters for surface roughness prediction are Wheel Speed (m/sec), Feedrate (mm/min) and Depth of Cut (mm). In this work, Surface Roughness average R was considered a to evaluate surface roughness quality. Result shows amongst the input parameters, the interaction between wheel speed and feed rate has the highest influence on the surface roughness (R ) and depth of cut has the least effect on R a a and so its effect can be neglected in regression method. Comparison of the results of two models with experiments was satisfactory. In addition, the results of Neural Network and Regression Models were compared to each other and Neural Network was found to be more precise than Regression Model in predicting surface roughness.

Abstract

Welding is used in fabrication as a permanent fastening method. Globally, welding technology has so many applications. This paper presents the residual stress distribution in angular joints of different included angles (45^o, 60^o, 75^o  and 90^o ). The Steel structures like off-shore structures, buried pipelines and steel trusses consist of a large number of tubular members joined by the welding process. Tubular members are joined in a variety of geometrical forms such as the angular joint, by welding. Tubular joints are structural discontinuities that can be easily involved with stress concentrations. However, the complicated residual stresses are unavoidably produced adjacent to the joints by welding. In this paper the residual stress distributions in welded tubular joints are analyzed by using a Steady-state Thermal Analysis. Characteristics of the residual stress distribution in welded tubular angle joints are investigated by the analysis of the result.

The stresses and deformations are developed using ANSYS Workbench software. The theoretical inputs of heat flow and temperature are given to the analysis software ANSYS Workbench. The resultant stresses and total deformation are generated from analysis software. The obtained stresses for different included angles (45^o, 60^o,  75^o and 90^o ) from the ANSYS Work Bench at same condition are compared with each other and best tubular joint is selected.

Abstract

Composite materials are those containing combination of different materials to cater to the requirement of properties that are not possible from a single material. They could be Natural or Engineered materials. Such materials often result in lightweight structures having high stiffness and tailored properties for specific applications, thereby saving weight and reducing energy needs. Biocomposites are composite materials made from Natural Fibers. This paper deals with preliminary experimental investigation on Mechanical and Thermal properties of Natural Fiber reinforced composites made from banana, hemp and wood fibers as reinforcements and high density polyethylene as a resin. It is observed that the biocomposite with hemp fiber exhibited better strength and thermal stability in comparison with other composites.

Abstract

The main aim of this paper is to improve the performance and to reduce the emissions of CI engine combustion. Experiments have been conducted on a single cylinder CI engine with normal injection and two pulse injection (split injection). From the simulated results and also existing experimental results it was observed that 10° dwell for double injection gives better results. In the present work, for split injection, existing cam shaft has been replaced with a modified cam shaft with a dwell angle of 10°, and experiments have been carried out with normal camshaft for single injection and with modified cam shaft for double injection. In double injection 50% of the total mass of the fuel was injected in the first pulse and the remaining 50% was injected after a dwell of 10°.

Experiments have been carried out for Single Cylinder Diesel Engine with the normal cam shaft which was existing in the engine for different loads (25%, 50%, 75% and 100%). The modified camshaft with double injection was tested with a dwell of 10°. In the first injection 50% of the fuel was injected and remaining fuel was injected after a dwell of 10°. The cycle peak pressure in double injection has been increased by 8% for full load, NO_X emission has been reduced by 8.67%, and CO levels were reduced by nearly 30%.

Abstract

Thermal energy storage plays a key role in the application of renewable energy sources and it contributes to the reduction of global CO₂ emissions. Thermal energy storage is commonly based on the sensible or latent-heat-storage  techniques. Latent-heat thermal storage is based on the absorption or release of heat when a storage material is changing its phase. The thermal storage materials suitable for latent-heat storage are called Phase-Change Materials (PCMs). PCMs have considerably higher thermal-energy-storage densities than the sensible-heat-storage materials and they are able to absorb large quantities of energy in a small range of temperatures during the phase change. The present work investigates, experimentally, the thermal performance of Sensible heat storage materials (Gravel and Granite) and phase change materials (Paraffin wax and MnCl₂ .4H₂O). Water is the Heat Transfer Fluid (HTF) used for 2 2 transferring heat from the constant power source (An immersion water heater). A Series of charging (Storing heat) and Discharging (Process of heat loss) processes are conducted to examine the thermal energy storage capacity of each material used. The significance of time-wise variation of Sensible Heat Storage Materials (SHS) and Phase Change Materials (PCM) temperatures during the discharging process was studied and analyzed.