ARPN Journal of Engineering and Applied Sciences                         ISSN 1819-6608
   
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ARPN Journal of Engineering and Applied Sciences                    May 2010 | Vol. 5  No. 5
   
Title:

Implicity dynamic simulation of contact behaviour of the quasi_isotropic carbon fibrous composite panels

Author (s):

Umar Farooq and Karl Grehory

Abstract:

In this paper computational modeling and simulation of the contact response of the quasi- isotropic carbon fibrous composite panels against blunt nose tip indenters has been studied. Mathematical modeling of spatial contact interaction was developed and incorporated into the finite element analysis software ABAQUS using implicit dynamic integration routine. Effect of ply orientation, thickness, indenter size, and variable loads were studied. From the comparisons of stresses, strains and deflections for isotropic and quasi-isotropic materials, it was observed that laminate thickness, material properties, loads and indenter sizes have significant affect on individual plies. The approach significantly reduces complexity in modeling some of the similar problems. The obtained results could be useful in improving the simulation modeling for design parameters. The selected results are included in the forms of graphs, contour plots and legend Tables.

 
 
 
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Title:

Optimum geometry of MEMS heat exchanger for heat transfer enhancement

Author (s):

Nusrat J. Chhanda, Muhannad Mustafa and Maglub Al Nur

Abstract:

The study is based on an analysis of MEMS heat exchanger of three different geometries: wavy, triangular and rectangular using water as test fluid. The problem is solved using finite element method. The aim of this analysis is to evaluate the performance of MEMS heat exchanger for different geometry and to obtain an optimum design for better heat enhancement. It is apparent from this work that rectangular surface heat exchanger shows the best performance for heat enhancement technique in comparison to other geometry. Moreover, it is also easy to manufacture. Therefore, the rectangular surface may be used instead of other configurations of heat transfer surfaces. In this analysis, emphasis is given on enhancing heat transfer area of MEMS heat exchanger by reducing the pitch which shows that 0.475 mm is the optimum pitch as further decrease of pitch length does not have any significant effect on the effectiveness and heat transfer.

 
 
 
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Title:

Experimental investigation of forced convective heat transfer in rectangular micro-channels

Author (s):

R. Kalaivanan and R. Rathnasamy

Abstract:

This paper investigates the experimental program on the study of heat transfer characteristics in micro-channels.  The two test sections used are of 47 and 50 micro-channels in rectangular cross-section of equivalent diameters 387 and 327 m respectively. Each channel of length 192 mm is fabricated on a 304 stainless steel substrate (230 mm x 160 mm x 1.6 mm) by photo chemical etching process. Covering the top with another plate of 0.5 mm thickness forms the channels by vacuum brazing. Experiments cover laminar region using the fluids ethanol, methanol and an ethanol-methanol mixture. The heat transfer coefficient is evaluated based on the heat carried away by the coolant and an average wall to mean fluid temperature difference. The Nusselt number is correlated through empirical correlations involving Reynolds number and Prandtl number with length parameter, the hydraulic diameter.

 
 
 
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Title:

Effects of tool setting on tool cutting angle on turning operation

Author (s):

K. V. Santha Kumari and Dipak Ranjan Jana

Abstract:

Accuracy of machined component is one of the most critical considerations for any manufacturer. Many key factors like cutting tool and its setting angle, machining conditions, resolution of the machine tool and the type of work place etc., play an important role. However, once these are decided upon, the consistent performance of the machine tool depends upon its ability to accurately position the tool tip vis--vis the required work piece dimension. Hence in this study the effect on Tool setting on cutting angle has been mathematically demonstrated. Lastly solution has been given that Why we align the centre and for what height, deviation of tool when set, then what change in tool angle should be done so as to get the result in such a way that there will be no effect on tool and work piece and we can get the greater accuracy of job in turning operation.

 
 
 
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Title:

Multicarrier trapezoidal PWM strategies based on control freedom degree for MSMI

Author (s):

R. Bensraj, S. P. Natarajan and V. Padmathilagam

Abstract:

This work proposes an additional clew for the carrier based PWM methods on control of multilevel inverters which is based on the combination of the Control Freedom Degree (CFD) and novel carrier/reference signals for multilevel cascaded inverter. The significance of the proposed CFD clew on multilevel PWM techniques are verified and well demonstrated by simulation for chosen five level inverter. This paper presents a novel approach for controlling the harmonics of output voltage of chosen Cascaded MultiLevel Inverter (CMLI) employing trapezoidal PWM switching strategies. Sub Harmonic PWM (SHPWM), Phase Shift PWM (PSPWM), Variable Frequency PWM (VFPWM) and Carrier Overlapping PWM (COPWM) techniques employed are evaluated for various modulation indices using spectrum of the output voltage and other performance measures such as crest factor, form factor etc and the use of inverter state redundancies to perform additional application specific control tasks. This paper focusses on MultiCarrier Trapezoidal PWM (MCTPWM) techniques with Phase Disposition (PD), Phase Shift (PS), Variable Frequency (VF) and Carrier Overlapping (CO) of carrier for the chosen CMLI. Simulations are performed using MATLAB/SIMULINK. It is observed that PD and CO methods provide output with relatively low distortion. It is also observed that CO is found to perform better since it provides relatively higher fundamental RMS output voltage and relatively lower stress on the devices.

 
 
 
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Title:

Experimental study of the effect of fuel injection pressure on diesel engine performance and emission

Author (s):

K. Kannan and M. Udayakumar

Abstract:

Diesel engines are the primary source of power for the heavy duty vehicles. The advantages of diesel engines are high fuel efficiency, reliability and durability. The performance and emission characteristics of diesel engine depend on many parameters. One of the important factors which influence the performance and emission of diesel engine is fuel injection pressure.  An experimental study was performed on a light duty direct injection diesel engine at 150 bar, 200 bar and 250 bar injection pressure to study its effect on performance and emission. The injection pressure was changed by adjusting the fuel injector spring tension. The performance and emission characteristics were presented graphically and concluded that they were found better at the fuel injection pressure 200 bar for the light duty engine.  

 
 
 
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Title:

Dual band MSA designs for GPS and GSM applications

Author (s):

Haider A. Sabti and Jabir S. Aziz

Abstract:

New designs of obtaining a dual frequency bands antenna operate on the dual frequency bands of Global Positioning System (GPS) and Global System for Mobile Communications (GSM) with a single-feed square micro-strip antenna are proposed and experimentally studied. The proposed designs are based on the different patch dimensions loaded with four rectangular slots in the form of cut from the sides of the square patch. The result of this work shows that the slots loaded into the square patch antennas offers further size reduction with multiband properties that can be used in GPS and GSM applications. Details of the design considerations of the proposed antennas are described, and experimental results of the obtained dual-band performances are presented and discussed.

 
 
 
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Title:

Numerical solution of longitudinal and torsional oscillations of cylinder with suction in a couple stress fluid

Author (s):

J. V. Ramana Murthy, G. Nagaraju and P. Muthu

Abstract:

The flow of a couple stress fluid generated by performing longitudinal and torsional oscillations of a porous circular cylinder subjected to constant suction at the surface of the cylinder is studied. A finite difference method is proposed to analyse the velocity components, in an infinite expanse of an incompressible couple stress fluid under vanishing couple stresses of type A condition or super adherence condition of type B on the boundary. The effects of couple stress parameter, Reynolds number and the ratio of couple stress viscosities parameter on transverse and axial velocity components are studied. The drag force acting on the wall of the cylinder is derived and effects of Couple stress parameters on drag are shown graphically.

 
 
 
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Title:

Strength of concrete incorporating aggregates recycled from demolition waste

Author (s):

R. Kumutha and K.  Vijai

Abstract:

The properties of concrete containing recycled aggregates were investigated.  Recycled aggregates consists of either crushed concrete (CC) or crushed bricks (CB) from the demolition wastes available locally. Laboratory trials were conducted to investigate the possibility of using recycled aggregates as the replacement of natural coarse aggregates or fine aggregates in concrete. A series of tests were carried out to determine the density, compressive strength, split tensile strength, flexural strength and modulus of elasticity of concrete with and without recycled aggregates. Natural coarse aggregates in concrete was replaced with 0%, 20%, 40%, 60%, 80% and 100% of crushed concrete aggregates. Natural fine aggregate in concrete was replaced with 0%, 20%, 40%, 60%, 80% and 100% of crushed brick aggregates.. For strength characteristics, the results showed a gradual decrease in compressive strength, split tensile strength, flexural strength and modulus of elasticity as the percentage of recycled aggregate used in the specimens increased.

 
 
 
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Title:

Hybrid modeling and optimization of hardness of surface produced by electric discharge machining using artificial neural networks and genetic algorithm

Author (s):

G. Krishna Mohana Rao, D. Hanumantha Rao and Anjaneya Prasad

Abstract:

The present work is aimed at optimizing the hardness of surface produced in die sinking electric discharge machining (EDM) by considering the simultaneous affect of various input parameters. The experiments are carried out on Ti6Al4V, HE15, 15CDV6 and M-250 by varying the peak current and voltage and the corresponding values of hardness were measured. Multiperceptron neural network models were developed using Neuro solutions package. Genetic algorithm concept is used to optimize the weighting factors of the network. It is observed that the developed model is within the limits of the agreeable error when experimental and network model results are compared. It is further observed that the error when the network is optimized by genetic algorithm has come down to less than 2% from more than 5%. Sensitivity analysis is also done to find the relative influence of factors on the performance measures. It is observed that type of material effectively influences the performance measures.

 
 
 
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Title:

Study on piezo-damping cyanate modified epoxy matrix glass fibre composite with lead zirconate titanate

Author (s):

Vijaya kumar K. R. and Sundareswaran V.

Abstract:

Mechanical properties of piezo-damping cyanate modified epoxy matrix glass fibre composite are investigated under 60% cyanate ester with varied lead zirconate titanate. The mechanical properties like tensile strength, flexural strength and fracture toughness are measured as per ASTM D3039, D790 and D5528 respectively. Epoxy/glass fibre with 60% cyanate loading (60EPCY) with good mechanical properties is the system chosen for varying load of PZT material (0%, 10%, 20% and 30%). Finite element method is used to measure frequency response, damping factor were obtained for piezo-damping cyanate modified epoxy matrix glass fibre composite.

 
 
 
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Title:

Simulation and measurement of very fast transient over voltages in a 245kv GIS and research on suppressing method using ferrite rings

Author (s):

J.V.G. Rama Rao, J. Amarnath and S. Kamakshaiah

Abstract:

Very fast transient over voltages are generated during the switching of disconnections in gas insulated substation. Such over voltages can cause mal functioning of protection circuits and control circuits and also initiates faults and influence on other components such as transformers. The suppression of VFTO (Very fast transient over voltage) is very important in GIS systems. There are some deficiencies in the existing suppressing methods. In this paper new idea for the suppressing VFTO by ferrite is put forward and the computer simulations were conducted on 245KV GIS models with and without ferrite rings and the results are verified with the experimental results. The simulation test results are closely matched with the experimental results so the use of magnetic rings to suppress VFTO is distinctly efficient. 

 
 
 
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