Indian Journal of Engineering & Materials Science


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VOLUME 13
CODEN : IEMSEW

NUMBER 3

JUNE 2006
ISSN : 0971-4588

  

CONTENTS

 

Engineering

 

 

Design of LQR controller for active suspension system

173

        M Senthil Kumar & S Vijayarangan

 

        [IPC Code: F16]

 

 

A survey of selected literature on important flow properties and computational fluid dynamics treatments of incompressible turbulent plane and roundjets in quiescent ambient

 

 

180

        Anupam Dewan, Manabendra Pathak & Anoop K Dass

 

        [IPC Code: F15D]

 

 

A combined CFD and network approach for a simulated turbine blade cooling system

195

        B V N Rama Kumar & B V S S S Prasad

 

        [IPC Code: F15D; F25B]

 

 

Comparison of barreling in unlubricated truncated cone billets during cold upset forging of various metals

 

202

        R Narayanasamy, A Syed Abu Thaheer & K Baskaran

 

        [IPC Code: B21J17/00]

 

 

Performance parameters optimization (multi-characteristics) of powder mixed electric discharge machining (PMEDM) through Taguchi’s method and utility concept

 

209

        H K Kansal, Sehijpal Singh & Pradeep Kumar

 

        [IPC Code: B05C; B23H1/00]

 

 

Optimization of micro welds in leaf springs used in automotive vehicles

217

        M L Aggarwal  R A Khan & V P Agrawal

 

        [IPC Code: G01N3/00]

 

 

A finite element based backcalculation program for flexible pavements

221

        Mehmet Saltan & Mustafa Karaşahin

 

        [IPC Code: E01C3/06]

 

 

Materials Science

 

 

Growth kinetic model for liquid phase electro epitaxial growth of GaSb

231

        D Mouleeswaran & R Dhanasekaran

 

        [IPC Code: C09K19/00]

 

Synthesis and characterisation of aluminium-silicon-silicon carbide composite

238

        J P Pathak, J K Singh & S Mohan

 

        [IPC Code: C22C47/00; C22C49/00]

 

 

Effects of expanded perlite aggregate and different curing conditions on the drying shrinkage of self-compacting concretes

 

247

        İbrahim Türkmen & Abdulhamit Kantarci

 

        [IPC Code: E04G21/08]

 

 

Studies on poly(vinyl chloride)/fatty acid blends as shape-stabilized phase change material for latent heat thermal energy storage

 

253

        Ahmet Sarı & Kamil Kaygusuz

 

        [IPC Code: C09K5/00]

 

 

 

Predicting adiabatic exponent as one of the important factors in evaluating detonation performance

 

259

        M H Keshavarz & H R Pouretedal

 

        [IPC Code: C06B]

 

 

__________

 

IPC: International Patent Classification

 

Int. Cl.8: International Classification 8th edition, 2006

 

 

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2006, pp. 173-179

 

 

 

Design of LQR controller for active suspension system

M Senthil Kumar & S Vijayarangan

 

The present paper aims at developing an active suspension for a passenger car by designing a controller using linear quadratic optimal control theory. In this work, two different control approaches are proposed, viz., conventional method (CM) and acceleration dependent method (ADM). A quarter car model with 3 degrees-of-freedom has been considered for the analysis. The performance of the active suspension system with two control approaches has been compared with that of passive one. It is concluded that active suspension system has a better potential to improve both the ride comfort and road holding, since the RMS (Root Mean Square) passenger acceleration has been reduced by 54.23% for active CM system and by 93.88% for active ADM system compared to passive one, and suspension travel has also reduced to about 37.5%.

IPC Code: F16

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2005, pp. 180-194

 

 

A survey of selected literature on important flow properties and computational fluid dynamics treatments of incompressible turbulent plane and round jets in quiescent ambient

Anupam Dewan, Manabendra Pathak & Anoop K. Dass

 

 

Turbulent jets are encountered in several practical applications in a large number of fields of engineering. Selected literature on incompressible turbulent plane and round jets in quiescent ambient has been reported in the present paper. These are classified as experimental and numerical works. One objective of the present survey is to report important flow features of incompressible turbulent jets observed by several researchers over a period of four decades. Experimental investigations of important flow properties of both types of jets, such as time-averaged velocity profiles, turbulent stresses, intermittency, growth rates, entrainment and role of coherent structures, transport of heat and passive scalar, higher order moments under a wide range of flow conditions have been reported. Performance and other issues of different turbulence models (both standard versions and modified versions to account for different effects) have also been discussed. Some important literature on large eddy simulations and direct numerical simulations of these flows has also been reported. Important observations from the literature survey have been summarized.

IPC Code:F15D

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2006, pp. 195-201

 

 

A combined CFD and network approach for a simulated turbine blade cooling system

B V N Rama Kumar & B V S S S Prasad

 

 

A combined computational fluid dynamics (CFD) and network analysis is proposed as an approach to solve complex flow and heat transfer problems. Perforated cylindrical passages with impingement and film cooling arrangement in a circular cylinder are considered as an example for demonstrating the methodology and simulated a cooled turbine blade geometry. Two networks namely, flow and thermal networks are developed. CFD calculations are performed to estimate loss factors and thermal resistances, which are used as input to the flow and thermal networks. Iterative procedures are adopted for solving the networks. Results of the pressure and temperature at different nodes, flow rates through the elements and film hole effectiveness in the span-wise.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2006, pp. 202-208

 

 

Comparison of barreling in unlubricated truncated cone billets
during cold upset forging of various metals

 

R Narayanasamy, A Syed Abu Thaheer  & K Baskaran

 

Experiments have been carried out to generate data on cold upset forging of unlubricated annealed commercially pure aluminium, copper and zinc solids of truncated cone billets. The measured curvatures of the barreled truncated cone billets of all the three metals are found to closely conform to the calculated values on the assumptions that the shape of the barrels is in the form of a circular arc. It is further found that the measured radius of curvature of barrels exhibited a linear relationship with a geometrical shape factor irrespective of the aspect ratios of the truncated cone billets. Further, an empirical relationship has been established between the measured radius of curvature of the barrels and stress ratio parameter. A comparative study of barreling behaviour of aluminium, copper and zinc, during upset forging operation in unlubricated condition is presented in this paper.

IPC Code: B21J17/00

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2006, pp. 209-216

 

 

Performance parameters optimization (multi-characteristics) of powder
mixed electric discharge machining (PMEDM) through Taguchi’s
method and utility concept

H K Kansal, Sehijpal Singh & Pradeep Kumar

 

Electrical discharge machining (EDM) is widely used in the production of dies. This paper describes an investigation into the optimization of the EDM process when silicon powder is suspended into the dielectric fluid of EDM. Taguchi’s method with multiple performance characteristics has been adopted to obtain an overall utility value that represents the overall performance of powder mixed EDM (PMEDM). The four input process parameters, viz., concentration of silicon powder added into the dielectric fluid, peak current, pulse duration and duty cycle, are optimized with consideration of multiple performance characteristics including machining rate (MR), surface roughness (SR) and tool wear rate (TWR). A modified powder mixed dielectric circulation system has been developed. Experiments have been performed on the newly designed experimental set-up developed in the laboratory. The obtained experimental results indicate that the peak current and concentration of the silicon powder suspended into dielectric fluid are most significant parameters. Moreover, the performance of PMEDM has improved over EDM. The predicted optimal values for MR, SR and TWR obtained for PMEDM are 1.22 mm3/min, 0.51 μm and 0.005 mm3/min respectively. The results are further verified by conducting confirmation experiments.

IPC Code:  B05C, B23H1/00

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2006, pp. 217-220

 

 

Optimization of micro welds in leaf springs used in automotive vehicles

 

M L Aggarwal, R A Khan  & V P Agrawal

 

 

Leaf springs withstand varying stresses and vibrations due to road conditions. Influence of high contact pressures and temperatures results in micro welds between two mating leaf surfaces. The work presented in this paper relates to improvement in fatigue and fretting fatigue performance of leaf springs used in automotive vehicles. The fatigue strength of 65Si7 spring steel has been evaluated experimentally as a function of shot peening parameters for application in automotive vehicles. Effects of shot peening and coating on fatigue life of leaf springs are discussed.

IPC Code: G01N3/00

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2006, pp. 221-230

 

 

A finite element based backcalculation program for flexible pavements

 

Mehmet Saltan  & Mustafa Karaşahin

 

In recent years pavement maintenance planning has become a main task among highway agencies. In order to determine the structural capacity of a flexible pavement, non-destructive testing equipment is used. Many countries use the falling weight deflectometer (FWD). It is possible to obtain deflection data and backcalculate the pavements’ mechanical properties. However, the method used affects the backcalculated values. A user-friendly finite element code has been developed in order to backcalculate pavement properties. The problem in using any finite element program is to prepare mesh data. In order to facilitate the mesh preparation, a mesh generator have been developed. The constitutive equations for the bituminous mixture are visco-elastic, linear elastic, visco-elasto-plastic; for granular layers non-linear elastic (K-q Model, Boyce Model, Pappin Model, Elhannani Model) and linear elastic, while for the subgrade non-linear elastic and linear elastic are used. Considerable deflection data are analyzed during the study using different models. The results indicate that the back-calculated properties depend upon the model which has been used. Therefore, using simple models can cause either over-design or under-design problems. The program is then tested against other back-calculation programs. The results indicate that the proposed program is better than other existing programs.

IPC Code: E01C3/06

 

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2006, pp. 231-237

 

Growth kinetic model for liquid phase electro epitaxial growth of GaSb

D Mouleeswaran & R Dhanasekaran

 

A two-dimensional growth kinetic model has been proposed to calculate the growth velocity and thickness of GaSb epitaxial layers grown by liquid phase electro epitaxy (LPEE) with a polycrystalline GaSb source material, which can be used to supply the solute species to the depleted growth solution during growth. The solute species (Sb) are continuously supplied from the source material to the growth solution by diffusion and electromigration. In the proposed theoretical model, numerical simulation has been followed to calculate the growth rate and thickness of the GaSb epitaxial layer from a Ga-rich solution. The theoretical findings indicate that the growth rate depends on the growth parameters such as growth temperature, growth time, diffusion of solute species, mobility of solute species, thickness of the substrate and source, thermoelectric effects and applied current density in the solution. The proposed model is based on the assumption that there is no nucleation in the solution. The growth rate, thickness of GaSb epitaxial layer and amount of dissolution of source material for different experimental growth conditions have been determined.

IPC Code: C09K 19/00

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June; 2006, pp. 238-246

 

 

Synthesis and characterisation of aluminium-silicon-silicon carbide composite

J P Pathak, J K Singh & S Mohan

 

Aluminium-silicon-silicon carbide composite was prepared by mechanical mixing (300 rpm) of silicon carbide powder (-300 mesh) in solidifying solid-liquid slurry of hypoeutectic, eutectic and hypereutectic compositions of aluminium-silicon alloy. Requisite amount of hot (300°C) silicon carbide powder was charged into agitating metallic melt of aluminium-silicon matrix alloy and mixing continued while dropping the temperature of the system. The mixing period was 3-4 min during which temperature of the system dropped to 15±5°C below the liquidus. On completion of mixing, plumbago crucible containing the composite slurry was taken out from the furnace and finally solidified composite was removed from the crucible for the further study. X-ray diffraction analysis indicated the presence of silicon carbide in the composite. Silicon carbide occurred in the grain boundry regions associated with silicon and fragmented dendrites together with eutectic mixture. Strength, hardness and wear resistance of composite increased with increase of silicon carbide content. Coefficient of friction of composite having higher amount of silicon carbide was always lower than the composite with lower amount of silicon carbide, whether the tests were conducted in lubrication, semi-dry and dry sliding conditions.

IPC Code: C22C47/00, C22C49/00

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2006, pp. 247-252

 

 

Effects of expanded perlite aggregate and different curing conditions on the drying shrinkage of self-compacting concrete

 

İbrahim Türkmen & Abdulhamit Kantarci

 

Fresh self-compacting concrete (SCC) flows into place and around obstructions under its own weight to fill the formwork completely and self-compact, without any segregation. The present study investigates drying shrinkage of SCC including mixtures of expanded perlite (EPA) and natural aggregates (NA) at six different curing conditions. The binder dosage is kept constant at 450 kg/m3 throughout the study. A superplasticizer is used as 2% (by weight) of Portland cement (PC) to reduce water/cement+mineral (w/cm) ratios and self-compacting. Specimens have been exposed to conditions of lime-saturated water (B1), dry in air (B2), coated with paraffin (B3), three times wetted in a day (B4), under wet-sack (B5) and 100% relative humidity (B6). It has been found that drying shrinkage of concrete is reduced by using EPA. The drying shrinkage of EPA concrete decreases with an increasing moisture content. It is also found that concrete exhibits a lower drying shrinkage in all time periods under the B1 curing conditions.

IPC Code: E04G21/08

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2006, pp. 253-258

 

 

Studies on poly(vinyl chloride)/fatty acid blends as shape-stabilized phase change material for latent heat thermal energy storage

Ahmet Sarı & Kamil Kaygusuz

 

The present study aims to prepare novel shape-stabilized phase change materials (PCMs) by using fatty acids [(lauric acid (LA), myristic acid (MA), palmitic acid (PA) and stearic acid (SA)] as PCM and poly(vinyl chloride) (PVC) as supporting material, and to determine their thermal properties such as melting temperature and the latent heat storage capacity. The maximum composition ratio of all fatty acids in the shape-stabilized PCMs has been found as 50 wt% in which no leakage of fatty acid is observed over their melting temperatures for several heating cycles. The miscibility of fatty acids with the PVC and the interaction between the blend components which is responsible for the miscibility has been proved by microscopic investigation and Infrared (IR) spectroscopy. The melting temperature and the latent heat of fusion of the shape-stabilized PCMs are measured by differential scanning calorimetry (DSC) analysis method. The melting temperatures and latent heats of the shape-stabilized PVC/LA, PVC/MA, PVC/PA and PVC/SA (50/50 wt%) PCMs are determined as 38.8, 49.2, 54.4 and 64.7oC and 97.8, 103.2, 120.3 and 129.3 J/g, respectively. The results indicate that the PVC/fatty acids blends as shape-stabilized PCMs have great potential for passive solar thermal energy applications in terms of their satisfactory thermal properties and advantages of easy preparation with desirable dimensions and direct utility in LHTES applications.

IPC Code: C09K 5/00

Indian Journal of Engineering & Materials Sciences

Vol. 13, June 2006, pp. 259-263

 

 

Predicting adiabatic exponent as one of the important factors in evaluating detonation performance

 

M H Keshavarz & H R Pouretedal

 

A new correlation is given to estimate the Chapman-Jouguet adiabatic (gamma) exponent, gCJ, as a criterion for choice among conflicting detonation pressure measurements at any loading densities, greater as well as less than 1 g/cc. The gCJ value obtained by new correlation is relatively insensitive to elemental composition and is primarily a function of loading density. Calculated gCJ by this procedure shows good agreement with respect to corresponding measured values as compared to complicated computer code BKW-EOS as well as reported empirical methods.

IPC Code: C06B