Mechanical Engineering

Glass fiber reinforced polymer composites are finding its increased applications in variety of engineering applications such as aerospace, automobile, electronics and other industries. The main objective of this study is to optimize the process parameters with multiple machinability characteristics. The performance characteristics considered were surface roughness (Ra), Cutting force (Fz) and cutting power (P). Optimal combination of process parameters can then be determined by Taguchi method using the grey relational grade as performance index. The process parameters considered were cutting speed, feed, depth of cut and fiber orientation angle (work piece). Experiments are planned according to Taguchi’s L25 orthogonal array in the design of experiments and were carried out on an all geared lathe using carbide (K20) cutting tool insert. The experimental results reveal that the feed is the most significant process parameter on the multiple machinability characteristics, this proposed method can be effectively used to improve the machining characteristics of GFRP composites.

Friction Stir Welding, a relatively new welding process, was developed in 1991 at The Welding Institute near Cambridge, England. In this process parts are mated together, rigidly fixtured, and joined in solid-state by forcing a rotating tool into the joint, and traversing that tool along the joint. This process creates weldments with properties comparable to the base metal and in most cases superior to traditional fusion welding techniques. During the Friction Stir Welding (FSW) process, the forging forces under the tool plastically deform the material, “stirring” the material around the tool pin and against the tool shoulder, thus joining the mated parts together. This process induces large shear forces in the plastically deforming material, raising the temperature of the material to approximately 80% of the melting temperature. The FSW process parameters such as tool rotational speed, welding speed, axial force, etc. play a major role in deciding the weld quality. In present investigation, the effect of processing parameters on mechanical properties of AA6082-O joints produced by friction stir welding was analyzed. Different welded specimens were produced by varying rotating speeds of the tool as 900 & 1200 rpm and by varying welding speeds as 50 & 63 mm/min. The FSW joints mechanical properties of the material such as yield strength, tensile strength and percentage of elongation were evaluated by means of tensile tests.

The aim of this study was to establish the relationship between the Stature and Popliteal Height Sitting, PHS. 161 male occupational bus drivers were randomly selected for anthropometric characterization of Stature and PHS using standard measuring equipment. The data were analyzed using SPSS 16.0 and Design-Expert 6.0.8. Then regression model was used to estimate PHS. The model shows that there is a linear relationship between the Stature and PHS with coefficient of determination (R2) of 0.8258 (p < 0.0001). The model mitigates time required for gathering anthropometric data. Designers would find this as a huge working tool for adequate productions.

A micromechanical 221 MHz silicon resonator is designed and demonstrated. The vibration mode can be characterized as a 2–D plate expansion that preserves the original square shape. The prototype resonator is fabricated of single-crystal silicon by reactive ion etching a silicon-on-insulator (SOI) wafer. The measured high quality factor and current output make the resonator suitable for reference oscillator applications. An electrical equivalent circuit based on physical device parametersis derived and experimentally verified.

Friction stir welding is a relatively new solid-state joining technique which is widely adopted in different industry fields to join different metallic alloys that are hard to weld by conventional Fusion welding. FSW welding of material ( like aluminium stainless steel copper etc.) with good weld quality it is essential to manufacture specified fixture having accurate clamping capacity, heat resistance, compressive strength of base plate, flexibility in the welded plate dimension and easy to operate before and after FSW process. In this paper everything is calculated properly with complete design criteria to fulfill above mentions requirement

Metal inert gas (MIG) welding is a fusion welding process having wide applications in industry. In any welding process, proper selection of input parameters is necessary to obtain good quality welds and consequently, increase the productivity of the process. Invariably, quality of welds is specified in terms of their ability to meet the service load requirements, zero-defect condition and/or cost-effective production. However, it is observed that a ‘Good Weld Bead Geometry’ can often be used to stipulate the weld quality as well as ensures one or more of the former considerations. The weld bead geometry is expressed in terms of six output parameters (called responses), viz., height of reinforcement (R), depth of penetration (P), weld bead width (W), per cent dilution (%D) and shape relationships such as weld penetration shape factor (W/P) and weld reinforcement form factor (W/R). This paper reports the experimental work with regard to developing a bead geometry-based criterion for acceptance of weldments prepared by MIG. Taguchi design method, comprising L16 orthogonal array (OA) was used to conduct the experimental with two replications and graphical method of analysis was used to arrive at the optimum combination of process parameters. The Responses were expressed in terms of six input process parameters, namely, wire feed rate (WFR), arc voltage (V), welding speed (WS), stand-off-distance (SOD), shielding gas flow rate (GFR) and parent material plate thickness (PT). Influence of the six main factors and their two-factor interactions were studied and the results are presented. It is observed that an increase in parameters like wire feed rate, welding speed, SOD and plate thickness will also result in a corresponding increase in reinforcement while they affect penetration in a negative way. On the other hand, a decrease in arc voltage results in an increase in reinforcement, but penetration decreases. The effect of GFR is typical, in the sense, as it is increased reinforcement decreases, but penetration shows an increasing trend. Further, weld bead width shows a positive correspondence with almost all input parameters. But, it has a negative relationship with SOD while it is unaffected by GFR. Also, the effect of 2-factor interactions have been studied and presented in this paper.

V-Trough solar simulator (VTSS) was designed and constructed at Measurements lab of Annamalai University and its performance was analyzed on indoor test facility. Integrating the heat pipe with V-Trough absorber plate can improve the system performance. VTSS system uses three different heat pipes such as circular, semicircular and Elliptical of same length 900 mm and diameter of 18 mm, 22 mm, 24 mm respectively. The experiment had been conducted by changing the heat pipes of the collector (VTSS). The output responses such as heat output, thermal resistance and overall efficiency has been analyzed with respect to each heat pipe experimentally by using commercial Design of Expert version DX 9 software by using Box- Behnken design of Response Surface Method (RSM). Contour diagram shows the factors effecting and thermal behaviour of the heat output, thermal resistance and overall efficiency has been shown. From the mathematical results and RSM optimization it is concluded that experimental setup integrated with circular heat pipe gives higher heat output and overall efficiency with less thermal resistance.

Reliability assessment popularly known as Weibull analysis is an exercise primarily concerned with reliability estimation and prediction with which failure process of a system can better be analyzed. Many situations like modeling failure processes, decision of effective maintenance policy, estimation of maintenance float factors, downtime assessment and reduction greatly rely on the parameters of the life distributions fitted to the failure data. As the Weibull distribution involves transcendental equation, determining parameters is quite difficult task. To this effect, a Nomograph is developed and presented in this paper to closely determine the Weibull parameters. The paper articulates the development of Nomograph and procedure for its implementation. Results and discussions carried out proves statistically that the results obtained using the Nomograph are better than the commonly used its counterparts.

In this study, the entropy generation of a fully developed laminar flow in circular segment ducts with constant wall heat flux is investigated. Entropy generation is obtained for various segment angels (2?), various wall heat flux and various Reynolds number. It is concluded that segment angel and wall heat flux have considerable effect on entropy generation. For the increasing value of these parameters, both entropy generation and pumping power ratio are increased at fixed Reynolds number.

This research work deals with analysis of simply supported rectangular plate under two different types of loading viz. centrally applied point load and uniformly distributed load (UDL). Four different sizes of plates were considered depending on the shape of material that allowed in the experiments. These plates were assumed to be constructed by isotropic material and subjected to point loading & UDL. The plates were supported under standard simply supported conditions at the two ends (left & right end views from the operator) so that the moment singularity is assumed at the tip of internal line support. Plate deflections were measured for all the plates under different loading conditions. These values were then validated using the ANSYS software. The results then compared and error was found out. The physical quantities of the plates and the extent of contact related to the level of loading in the case of free contact are provided in the present work.