Indian Journal of

Engineering & Materials Sciences

        

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VOLUME 16

NUMBER 4

                     AUGUST 2009

CODEN : IEMSEW

ISSN : 0971-4588

 

CONTENTS

 

Engineering

 

 

 

Mathematical model and rule extraction for tool wear monitoring problem

 

        using nature inspired techniques

205

        S N Omkar, J Senthilnath & S Suresh

 

 

 

Mean flow field measurements in an axisymmetric conical diffuser with and

 

        without inlet flow distortion

211

        E Karunakaran & V Ganesan

 

 

 

Seismic performance evaluation methodologies for civil engineering         structures

 

220

        C Antony Jeyasehar, K Sathish Kumar, K Muthumani & N Lakshmanan

 

 

 

CFD approach for design optimization and validation for axial flow

 

        hydraulic turbine

229

        Vishnu Prasad, V K Gahlot & P Krishnamachar

 

 

 

Artificial neural networks for predicting low temperature performances of

 

        modified asphalt mixtures

237

        Yuksel Tasdemir

 

 

 

Bridge truss optimization under moving load using continuous and

 

        discrete design variables in optimization methods

245

        Vedat Toğan & Ayşe T Daloğlu

 

 

 

Discrete singular convolution algorithm for non-linear transient response of

 

        circular plates resting on Winkler-Pasternak elastic foundations

 

        with different types of dynamic loading

259

        Ömer Civalek & Baki Öztürk

 

 

 

Use of lime cement stabilized pavement construction

269

        M Anjan Kumar & G V R Prasada Raju

 

 

 

Materials Science

 

 

 

Simple fabrication of Mg2Si thermoelectric generator by spark plasma         sintering

 

277

        M J Yang, L M Zhang, L Q Han, Q Shen & C B Wang

 

 

 

Nanostructured silver-graphite electrical contact materials processed

 

        by mechanical milling

281

        Bharati R Rehani, P B Joshi & V K Kaushik

 

 

 

Preparation and characterization of nickel doped, A and B Site LaCoO3         perovskite

 

288

        Chandrakant Singh & Meeta Rakesh

 

 

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol.16, August 2009, pp. 205-210

 

 

Mathematical model and rule extraction for tool wear monitoring problem using nature inspired techniques

S N Omkar, J Senthilnath & S Suresh

 

In this paper, pattern classification problem in tool wear monitoring is solved using nature inspired techniques such as Genetic Programming (GP) and Ant-Miner (AM). The main advantage of GP and AM is their ability to learn the underlying data relationships and express them in the form of mathematical equation or simple rules. The extraction of knowledge from the training data set using GP and AM are in the form of Genetic Programming Classifier Expression (GPCE) and rules respectively. The GPCE and AM extracted rules are then applied to set of data in the testing/validation set to obtain the classification accuracy. A major attraction in GP evolved GPCE and AM based classification is the possibility of obtaining an expert system like rules that can be directly applied subsequently by the user in his/her application. The performance of the data classification using GP and AM is as good as the classification accuracy obtained in the earlier study (i.e. using ANN approach).

Keywords: Tool wear monitoring; Genetic Programming; Ant-Miner

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, August 2009, pp. 211-219

 

Mean flow field measurements in an axisymmetric conical diffuser with and without inlet flow distortion

E Karunakaran & V Ganesan

 

The prime objective of this paper is to present the details of the experimental investigation and measurements made in an axisymmetric 5° conical diffuser model. The flow through a diffuser is studied with and without the inlet flow distortion. A simple cylindrical bluff body placed at the inlet of the diffuser creates the inlet flow distortion. A 5 mm diameter five-hole pitot sphere of cobra type has been used along with electronic digital manometers for the measurements. The velocity at the near wall regions and wake regions are well captured with the five-hole probe. The 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 flows. Performance and flow characteristics along the centerline of diffuser are presented.

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, August 2009, pp. 220-228

 

 

Seismic performance evaluation methodologies for civil engineering structures

C Antony Jeyasehar, K Sathish Kumar, K Muthumani & N Lakshmanan

 

There is a strong need for evaluating the adequacy of seismic performance of civil engineering structures following the damage and collapse of numerous structures during recent earthquakes. In addition, the adequacy of seismic performance of the older structures in regions of high seismicity, which are designed prior to the advent of revised seismic deign codes, is also a matter of growing concern. Seismic performance evaluation of civil engineering structures is an iterative process involving alternate stages of experimentation and computation. Several experimental methodologies including quasi-static testing, effective force testing, shake table testing, pseudo dynamic testing and real time dynamic hybrid testing and computational methodologies based on different numerical time stepping procedures are used to simulate and evaluate the seismic performance of civil engineering structures.  In this paper a broad overview on the existing computational and experimental seismic performance evaluation methodologies is reported. The paper also presents the genesis, development and mathematical formulation of the pseudo dynamic testing method in detail and highlights the merits and demerits of the method over the other experimental seismic performance evaluation methods.

Keywords: Seismic performance, performance evaluation, earthquake engineering, shake table testing, effective force testing, pseudo dynamic testing, real time dynamic hybrid testing.

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, August 2009, pp. 229-236

 

 

CFD approach for design optimization and validation for
axial flow hydraulic turbine

Vishnu Prasad, V K Gahlot & P Krishnamachar

 

The conventional method to assess turbine performance is its model testing which becomes costly and time consuming for several design alternatives in design optimization. Computational fluid dynamics (CFD) has become a cost effective tool for predicting detailed flow information in turbine space to enable the selection of best design. In the present paper, 3D real flow analysis in an experimentally tested axial flow turbine has been carried out and different flow parameters are computed at three operating regimes to find the best operating regime. The computed efficiencies are critically compared with experimental values and found to bear close comparison.

Keywords : Computational fluid dynamics, Efficiency, Lift, Blade circulation, Degree of reaction

 

 

Indian Journal of Engineering & Materials Sciences

Vol.16, August 2009, pp. 237-244

 

 

Artificial neural networks for predicting low temperature performances of modified asphalt mixtures

Yuksel Tasdemir

 

In this study, the estimation of the low temperature performance of modified asphalt mixtures is investigated by using multi-layer perceptrons (MLP) which is one of the artificial neural networks (ANNs) techniques and general linear model (GLM). The fastest MLP training algorithm, that is the Levenberg-Marquardt algorithm, is used for optimization of the network weights. The ANN test results are compared to GLM results. GLM has, historically, been used to model the low temperature performance (fracture temperature and fracture strength) of asphalt pavements. The data used in the ANN model and GLM are arranged in a format of four input parameters that cover additive type, asphalt binder content, aging level and air void content, and output parameters which are the fracture temperature and the fracture strength. Based on the comparisons, it is found that the ANN generally gives better fracture temperature and fracture strength estimates than the GLM technique.

Keywords: Artificial neural network; General linear model; Thermal stress restrained specimen test; Fracture temperature; Fracture strength

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, August 2009, pp. 245-258

 

 

Bridge truss optimization under moving load using continuous and discrete design variables in optimization methods

Vedat Toğan & Ayşe T Daloğlu

 

The aim of this work is to minimize the weight of steel bridge trusses under the limitations imposed on its behaviour by the design codes when it is subjected to moving load (HS20-truck). Adaptive manner operators are included to enhance the capability of GA. Design examples are solved to illustrate the applicability of proposed algorithm. Results are compared with those evaluated by various optimization methods with continuous design variables such as sequential convex programming (SCP), sequential quadratic programming (SQP) and evolution strategy (EVOL). It can be concluded that the results obtained by GA is meaningful, more suitable for practice and GA performs well to find minimum weight of the bridge trusses under moving load.

Keywords: Bridge truss; Optimization methods; Evolutionary computation; Genetic algorithm

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, August 2009, pp 259-268

 

 

Discrete singular convolution algorithm for non-linear transient response of circular plates resting on Winkler-Pasternak elastic foundations with different types of dynamic loading

Ömer Civalek & Baki Öztürk

 

Nonlinear dynamic analysis of circular plates on two parameter elastic foundations is studied. Winkler and Pasternak models of elastic foundation are used. The nonlinear partial differential equations obtained from von Karman’s large deflection plate theory have been solved by using the discrete singular convolution (DSC) in the space domain and the harmonic differential quadrature (HDQ) method in the time domain. The influence of stiffness of Winkler (K) and Pasternak (G) foundation on geometrically nonlinear dynamic response of plates is investigated. The influence of damping on the nonlinear dynamic response has also been studied. Numerical results obtained by the application of present technique compare well with the results available in literature.

Keywords:  Discrete singular convolution, Circular plates, Harmonic differential quadrature, Nonlinear transient analysis, Winkler-Pasternak elastic foundation

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, August 2009, pp. 269-276

 

 

Use of lime cement stabilized pavement construction

M Anjan Kumar & G V R Prasada Raju

 

Expansive clay is a major source of heave induced structural distress. Swelling of expansive soils causes serious problems and produce damages to many structures. Many research organizations are doing extensive work on waste materials concerning the feasibility and environmental suitability. Fly ash, a waste by product from coal burning in thermal power stations is abundant in India causing severe health, environmental and disposal problems. Attempts are made to investigate the stabilization process with model test tracks over expansive subgrade in flexible pavements. Cyclic plate load tests are carried out on the tracks with chemicals like lime and cement introduced in fly ash subbase laid on sand and expansive subgrades. Test results show that maximum load carrying capacity is obtained for stabilized fly ash subbase compared to untreated fly ash subbase.

Keywords: Expansive soil, Fly ash, Lime, Cement, Flexible pavement

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, August 2009, pp. 277-280

 

 

Simple fabrication of Mg2Si thermoelectric generator by
spark plasma sintering

M J Yang, L M Zhang, L Q Han, Q Shen & C B Wang

 

Raw Mg and Si powders have been used to fabricate Mg2Si bulk thermoelectric generator by spark plasma sintering (SPS). The optimum parameters to synthesize pure Mg2Si are found to be 823 K-0 MPa-10 min with excessive content of 10wt% Mg from the stoichiometric Mg2Si. Mg2Si bulk has been firstly synthesized and densified simultaneously at low temperature (823 K) and high pressure (higher than 100 MPa) from the raw powder, but Mg and Si not react completely, and the sample is not very dense with some microcracks on the surface. Then, Mg and Si powders firstly reacted at 823 K-0 MPa-10 min in SPS chamber to form Mg2Si green compact, again sintered by SPS at 1023 K-20 MPa-5 min. The fabricated sample only contained Mg2Si phase with high relative density (nearly 100%).

Keywords: Mg2Si, Spark Plasma Sintering

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 16, August 2009, pp. 281-287

 

 

Nanostructured silver-graphite electrical contact materials processed
by mechanical milling

Bharati R Rehani, P B Joshi & V K Kaushik

 

In last few decades there has been a growing interest in nanostructured materials in view of their improved mechanical, physical and chemical properties. A wide variety of techniques have been developed to synthesize nanopowders including high-energy milling or mechanical alloying (MA) for producing bulk nanostructures. High-energy milling is used for preparation of elemental and composite powders of different metals and non-metals. Literature reports the synthesis of ductile-ductile composites such as aluminium-graphite and copper-graphite by MA owing to its potential benefits in terms of improved mechanical properties. Reports are also there on the application of this technology for processing of silver-graphite contact materials offering improved switching properties.

 

 

Indian Journal of Engineering & Materials Sciences

Vol.16, August 2009, pp. 288-290

 

Preparation and characterization of nickel doped, A and B Site LaCoO3 perovskite

Chandrakant Singh & Meeta Rakesh

 

This paper presents an approach to the preparation of LaCoO3 perovskite and nickel doped LaCoO3 in A and B site both, to see the effect of nickel doping in both the site catalyst synthesized by co-precipitation method. The novelty of the experiment is nickel doped in A-site of LaCoO3 perovskite to see effect of nickel doping into their physical properties (i.e. crystalline phase and microstructure). Samples have been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Branauer–Emmett-Teller (BET) nitrogen adsorption technique.

Keywords: Perovskite; LaCoO3, La1-x Ni xCoO3 , LaCo1-y NiyO3; Co-precipitation method