Volume: 5
Number: 1
January-June 2006

To see an article directly, click its Title. To see abstract, click its [Abstract] link.

• SIMULATION OF THE PLASTIC FIELD IN THE DEFORMATION ZONE OF SURFACE ROLLING TOOLS UNDER VARIABLE WORK HARDENING CONDITIONS
  Md. Nurul Absar Chowdhury, Md. Anayet Ullah Patwari
  Abstract PDF
  SIMULATION OF THE PLASTIC FIELD IN THE DEFORMATION ZONE OF SURFACE ROLLING TOOLS UNDER VARIABLE WORK HARDENING CONDITIONS
  Md. Nurul Absar Chowdhury, Md. Anayet Ullah Patwari

  Abstract

  Longevity of the machine or machine parts depends on the quality of surface layer formed during mechanical working, on the other hand the quality of the surface layer depends on the mechanisms of formation of surface layer. In order to control the quality of the surface layer it is needed to study the formation of surface layer during the mechanical working process. The stresses developed during the work hardening by surface rolling could be studied by slip-line theory or by finite element method. This project employs the slip-line theory in understanding the formation of surface layer.
  Development of computer technology and its application in modelling processes avoids costly experimental methods and extensive calculation. In this work, on the basis of theoretical model, computer programming has been developed for the simulation of the plastic field in the deformation zone. Profile of deformation zone has been taken as input of the program. Simulations were done for different profiles. The results were compared with the experimental data. Comparison shows that the proposed simulation method can be used for analyzing the plastic field with sufficient accuracy. Developed computer software could be used in order to accelerate the procedure for stress analysis.
• AN EXPERIMENTAL STUDY OF CRYOGENiCCOOLING EFFECTS IN MACHINING AISI-4140 STEEL
  N. R. Dhar, M. M. A. Khan
  Abstract PDF
  AN EXPERIMENTAL STUDY OF CRYOGENiCCOOLING EFFECTS IN MACHINING AISI-4140 STEEL
  N. R. Dhar, M. M. A. Khan

  Abstract

  Application of conventional cutting fluids do not serve the purposes effectively particularly under high cutting velocity and feed. Besides, such cutting fluids pollute the environment in high production machining and grinding. Cryogenic cooling seemed to be quite effective in reducing the high cutting temperature, which impairs product quality and reduces tool life. Cryogenic cooling is an environment friendly clean technology for desirable control of cutting temperature. The present work investigates the role of cryogenic cooling by liquid nitrogen jet on chip formation, cutting forces and cutting temperature in turning AISI 4140 steel under industrial speed-feed conditions. The experimental results indicate significant reduction in cutting temperature on application of cryogen. Such reduced temperature along with reduction in chip-tool contact length and favorable chip-tool interaction also provide significant reduction in cutting forces.
• DESIGNING AN ATM NETWORK BASED ON DISTRIBUTED DATABASE SYSTEMS
  Md. Rahat Hossain, Abdullah Azfar,Golam Shagadul Amin Talukder, S M Faisal, Abdullah Al Hasib
  Abstract PDF
  DESIGNING AN ATM NETWORK BASED ON DISTRIBUTED DATABASE SYSTEMS
  Md. Rahat Hossain, Abdullah Azfar,Golam Shagadul Amin Talukder, S M Faisal, Abdullah Al Hasib

  Abstract

  Automated teller machines (ATM) have become a part and parcel of new generation banking. The ATM network is fully based on centralized database environment. Time of transaction varies according to the distance between the ATM and centralized database. A more convenient approach would be to make a distributed database environment for ATM networks. This will make life easier, tasks secured and efficient utilization of resources. In this paper we have proposed a design of an ATM network based on distributed database environment. We have also discussed the costs and benefits of our design by allocating fragments on different sites.
• DESIGN AND IMPLEMENTATION OF AN MTPA FUZZY CONTROLLER FOR IPMSM DRIVES
  M. J. Hossain, M. A. Hoque, M. M. Ali, K.K. Islam, M. A. Rahman
  Abstract PDF
  DESIGN AND IMPLEMENTATION OF AN MTPA FUZZY CONTROLLER FOR IPMSM DRIVES
  M. J. Hossain, M. A. Hoque, M. M. Ali, K.K. Islam, M. A. Rahman

  Abstract

  This paper presents design and implementation techniques of a maximum torque per ampere (MTPA) fuzzy controllers for an interior permanent magnet synchronous motor (IPMSM) drive. The complete drive system with Proportional-Integral (PI) controller and the fuzzy based MTPA controllers has been simulated and experimentally implemented in real time using a digital signal processor DS 1102 with a laboratory prototype 1 hp interior permanent synchronous motor. Contrary to the conventional control of IPMSM with d-axis current equals to zero, a non-linear expression of d-axis current has been derived and subsequently incorporated in the control algorithm for maximum torque operation of the fuzzy based IPMSM drive. In this work, it is observed that less stator current is required to produce the same amount of torque than that required for the zero d-axis current. This technique eventually overcomes the rating limitation of the inverter and motor in the drive system. Simulation and experimental results prove the efficacy of the MTPA fuzzy controller based IPMSM drive over the PI based IPMSM drive.