Indian Journal of
Engineering & Materials Sciences

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VOLUME 16

NUMBER 1

FEBRUARY 2009

CODEN : IEMSEW

 

ISSN : 0971-4588

 

††† CONTENTS

 

   Engineering

Investigation on the characteristics of a new high frequency three-way proportional pressure reducing valve in variable valve system of automobile engine

 

7

††††††† Jin-rong Liu, Bo Jin, Ying-jun Xie, Ying Chen & Zhen-tao Weng

 

 

 

Experimental study of recirculating flows induced by vane swirler

14

††††††† R Thundil Karuppa Raj & V Ganesan

 

 

 

Optimizing feed and radial forces in CNC machining of P-20 tool steel through Taguchiís parameter design approach

 

23

††††††† Aman Aggarwal, Hari Singh, Pradeep Kumar & Manmohan Singh

 

 

 

Failure analysis of a spring for a fuel pump bracket assembly

33

††††††† Himadri Roy, Debashis Ghosh, Tapas Sahoo & Awadhesh Shukla

 

 

 

Static analysis of thick skew laminated composite plate with elliptical cutout

37

††††††† M S R Niranjan Kumar, M M M Sarcar & V Bala Krishna Murthy

 

 

 

Materials Science

 

 

 

Optimization of high speed turning parameters of superalloy Inconel 718material using Taguchi technique

 

44

††††††† Dinesh Thakur, B Ramamoorthy & L Vijayaraghavan

 

 

 

Process and die design for square tube extrusion

51

††††††† K K Pathak, S Lomash & A K Jha

 

 

 

Tailoring of density in carbon foams

56

††††††† S C Sharma, N K Ramakrishna Naidu, T S Lakshmanan , M C Mittal,

 

††††††† P P Sinha & V K Vaidyan

 

 

 

Relationship between thermal stability and molecular structure of polynitro arenes

61

††††††† M H Keshavarz, H R Pouretedal & A Semnani

 

 

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, February 2009, pp. 7-13

 

 

Investigation on the characteristics of a new high frequency three-way proportional pressure reducing valve in variable valve system
of automobile engine

 

Jin-rong Liu, Bo Jin, Ying-jun Xie, Ying Chen & Zhen-tao Weng

 

In this study, a new high frequency three way proportional pressure-reducing valve has been developed. By reducing the turns of the coil and using a high speed current amplifier, the responding time of the proportional solenoid is reduced to less than 1 ms. The steady and dynamic analyses show that the output pressure is proportional to the coil current and the dynamic bandwidth can be increased by increasing the coil current. An experimental system is built up and results well agreed with the theoretical and simulation analyses. The bandwidth of the valve is about 130 Hz at -3dB, which can meet the demand of automobile engine with maximum speed of 3000 rpm.

Keywords: High frequency, Proportional pressure reducing valve, Variable valve, Proportional amplifier, Simulation

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, February 2009, pp. 14-22

 

 

Experimental study of recirculating flows induced by vane swirler

R Thundil Karuppa Raj & V Ganesan

 

The core objective of this study is to present the details of the experimental procedure and measurements made in an axisymmetric swirler model. The flow through 8 blade 30į vane swirler is studied experimentally. An overlap angle of 30į is provided between the vanes for the proper guidance of the flow through swirler. A hemi spherical bluff body is attached to the hub in order to overcome the inlet flow field distortion. A 5 mm diameter five-hole pitot sphere of cobra type has been used along with electronic digital manometers for the measurements. A computer aided traversing mechanism supported with Streamware software automatically controls the traversing of the probe. The recirculation velocities at the center core and corner regions are well captured with the five-hole probe. Five-hole pitot probe measurements along the entire length of the model at different stations, allow the determination of axial mean velocity component and pressure field parameters, which provide comprehensive information to aid and understand such complex recirculation flows. Flow field characteristics downstream of the swirler at different axial locations are examined in detail. The recirculation length and width are found to be strongly dependent on the amount of turbulence created by the vane swirler.

†††††††††† Keywords: Swirler, Adverse pressure gradient, Vane angle, Recirculation region, Five-hole probe.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, February 2009, pp. 23-32

 

 

Optimizing feed and radial forces in CNC machining of P-20 tool steel through Taguchiís parameter design approach

 

Aman Aggarwal, Hari Singh, Pradeep Kumar & Manmohan Singh

 

The objective of the paper is to obtain an optimal setting of CNC machining process parameters (cutting speed, feed rate, depth of cut, nose radius and cutting environment) resulting in optimal values of the feed and radial forces while machining P-20 tool steel with TiN coated tungsten carbide inserts. The effects of the selected process parameters on the chosen characteristics and the subsequent optimal settings of the parameters have been accomplished using Taguchiís parameter design approach. The analysis of the results shows that the optimal settings for low values of feed and radial forces are high cutting speed, low feed rate and depth of cut, small nose radius and cryogenic cutting environment.

Keywords: Cutting parameters, CNC machining process, Feed force, Radial force, Taguchi approach, P-20 tool steel, Coated carbide inserts

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, February 2009, pp. 33-36†††††††

 

 

Failure analysis of a spring for a fuel pump bracket assembly

Himadri Roy, Debashis Ghosh, Tapas Sahoo & Awadhesh Shukla

 

This investigation is primarily aimed to examine the premature failure of a spring used in a fuel pump bracket assembly. Preliminary visual examinations along with detailed SEM studies are made on the damaged surface and fracture surface of the failed spring. In addition, microstructural investigations along with hardness measurements are carried out to understand the reason for the premature failure. Finally, it is concluded that improper heat treatment of the spring material is responsible for failure.

†††††††††† Keywords: Spring, SEM, Pearlite, Delamination, Failure

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, February 2009, pp. 37-43

 

 

Static analysis of thick skew laminated composite plate with elliptical cutout

M S R Niranjan Kumar, M M M Sarcar & V Bala Krishna Murthy

 

The behaviour of a laminated composite skew plate with elliptical hole subjected to transverse pressure loading has been investigated in the present analysis. A finite element method which works on the basis of three-dimensional theory of elasticity is employed to evaluate the transverse deflection, in-plane stresses and interlaminar stresses. The results obtained by varying the skew angle, size of the cutout and the effect of elliptical cutout orientation are discussed. The magnitudes of the transverse deflection and in-plane stresses for pressure loading are observed to be less at higher skew angles and for larger size of the cutout. It is also observed that the configuration 3 of the ellipse (major axis of the ellipse parallel to inclined sides of the skew plate) is found to be better with respect to the major stresses point of view. The solutions of skew structures considered in the present analysis may be useful for the construction of safe and efficient structures like skew bridges and swept wings of aircraft structures.

†††††††††† Keywords: FEM, Skew laminate, Cutout, Interlaminar stresses

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, February 2009, pp. 44-50

 

 

Optimization of high speed turning parameters of superalloy Inconel
718 material using Taguchi technique

 

Dinesh Thakur, B Ramamoorthy & L Vijayaraghavan

 

Superalloy, Inconel 718 is widely used in sophisticated applications due to its unique properties desired for the engineering applications. Due to its peculiar characteristics machining of Superalloy Inconel 718 is difficult and costly. The present work is an attempt to make use of Taguchi optimization technique to optimize cutting parameters during high speed turning of Inconel 718 using tungsten carbide cutting tool. Taguchi method is a powerful design of experiments (DOE) tool for engineering optimization of a process. It is an important tool to identify the critical parameters and predict optimal settings for each process parameter. Analysis of variance (ANOVA) is used to study the effect of process parameters and establish correlation among the cutting speed, feed and depth of cut with respect to the major machinability factor, cutting forces such as cutting force and feed force. Validations of the modeled equations are proved to be well within the agreement with the experimental data.

†††††††††† Keywords: Cutting force, Feed force, Chip analysis, Taguchi method

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, February 2009, pp. 51-55

 

 

Process and die design for square tube extrusion

 

K K Pathak, S Lomash & A K Jha

 

In this study, die profile of the square tube extrusion process is optimized to produce microstructuarlly sound product at maximum production speed and minimum left out material in the die. The design problem is formulated as a nonlinear programming model, which is solved using genetic algorithms (GA). Selection of the processing parameters is carried out using dynamic material modeling (DMM). Using this approach a square tube extrusion process is successfully designed.

†††††††††† Keywords: Microstructure; Die profile; Simulation, Processing parameters; Extrusion; Genetic algorithms

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, February 2009, pp. 56-60

 

 

Tailoring of density in carbon foams

S C Sharma, N K Ramakrishna Naidu, T S Lakshmanan, M C Mittal, P P Sinha & V K Vaidyan

 

Cell-size of the sacrificial polymeric scaffolding and concentration of the impregnating phenolic resin are taken as two variables for tailoring density in the carbon foam. Effects of cell-size and resin-concentration on density of carbon foam are studied under three categories: (i) individual effect of varying cell-size with fixed resin-concentration, (ii) individual effect of varying resin-concentration with fixed cell-size, and (iii) synergistic effect of varying cell-size and resin-concentration. For a fixed resin-concentration and particularly for lower concentration of 10%, density marks a small incremental effect with the reduction in cell-size. It increases from 0.041 to 0.055 g/cc for a cell-size of 30 PPI (pores per inch) and 80 PPI respectively. For a fixed cell-size and particularly for lower cell-size of 80 PPI, density shows a large incremental effect with increase in resin-concentration. Density increases from 0.055 to 0.210 g/cc for a resin-concentration of 10% and 90% respectively. Under the combined effect of decreasing cell-size and increasing resin-concentration, density records a massive increase of 412.2% from initial combination of 30 PPI cell-size and 10% resin-concentration to last combination of 80 PPI cell-size and 90% resin-concentration.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, February 2009, pp. 61-64

 

 

Relationship between thermal stability and molecular structure of polynitro arenes

M H Keshavarz, H R Pouretedal & A Semnani

 

A simple relationship has been derived to predict thermal stability of CHNO polynitro arenes on the basis of onsets of thermal decomposition, which can be obtained by means of non-isothermal differential thermal analysis (DTA). The model is optimized using a set of 12 polynitro arenes so that R-squared value or the coefficient of determination of the new correlation is 0.95. The new correlation has also been applied to 6 polynitro arenes explosives from a variety of chemical families in order to assess the predictive capability of new method. Predicted results are close to the measured values for all of tested polynitro arenes on the basis DTA.