Contents of Journal of Mechanical Engineering 56, 6 (2005) 





MUCHA, Z.: Temperature conditions for laser thermal forming process     319

AL-ATABI, M. T.: A subsonic jet thrust vector control
using fluidic means                                                     332

GROS, P.:  An advanced plasma cutting unit for both-side bevelling
on metal parts                                                          339

BÓNIŠOVÁ, M.: On the influence of superfinishing tools on the surface                                          353
roughness achieved (in Slovak)                                          353

Letter to the Editor
MD SAAD, M. H., NOR, M. J. M., KIAT, K. W.: Design and development
of an economical driving simulator                                      364

Abstracts



Temperature conditions for laser thermal forming process

ZYGMUNT MUCHA

Studies on touchless bending of metal plates by use of laser beam are presented. Laser beam is modelled as a heat source of finite dimensions moving over the plate surface. The analytical approximation of Ashby and Easterling of the temperature field in material is adopted, so continuous temperature distribution in the material yield region is considered. The bend angle is investigated as a function of processing parameters, material parameters and initial material temperature. The derived solutions for bend angle are used to analyse the dependence of the bend angle on initial material temperature. The theoretical results are compared with the experimental value of the bend angle for different materials. The optimum value of initial temperature is found when the bend angle is maximum. This dependence helps to derive the critical temperature at which the material yield stress limit can be assumed zero. It is an important material parameter for optimization and control of initial and surface temperatures of the thermal bending process.

A subsonic jet thrust vector control using fluidic means

MUSHTAK TALIB AL-ATABI

Fluidic thrust vectoring of a subsonic jet is examined by the asymmetric application of coflow to the jet shear layers. When coflow is applied to one side of a two-dimensional jet, the entrainment of the flow due to the Coanda effect gives a rise to the cross-stream pressure gradient resulting in an asymmetric alteration of the direction of the exhaust jet, which represents a thrust vectoring effect. This study reports a computational fluid dynamics (CFD) investigation of the concept. As the mass flow rate of the secondary flow increases the vectoring angle of the main stream increases.

An advanced plasma cutting unit for both-side bevelling on metal parts

PETER GROS

For successful welding, the edges of the parts to be joined often require a bevelled edge. For many applications, the most productive way to create a bevelled edge on a metal part is to use a CNC oxy-fuel or plasma torch system. However both-side chamfer on the grained edge using the single-torch plasma machines requires triple machining time. That was a question: "How to reduce machining time for both-side plasma bevelling?" The paper introduces a new advanced prototype of the 3-torch plasma cutting unit for both-side bevelling. This machine has been developed in cooperation of the Faculty of Mechanical Engineering, STU in Bratislava and Microstep-Group.

On the influence of superfinishing tools on the surface roughness achieved

MONIKA BÓNIŠOVÁ

This contribution deals with problem of cutting efficiency by superfinishing. Some selected parameters which influence the process of superfinishing are revealed. Actually, there are surface roughness and material loading ratio of the profile after superfinishing considered. In the tests, measured out quantities of surface roughness Ra, Rz, Rmrc of the etalon machined material were compared. Those were acquired by different specified superfinishing tools from various suppliers and consequently their optimal combination was proposed – proposition of a tool etalon. The cutting tool etalon was proposed for steel as a machined material.

Design and development of an economical driving simulator

MOHD HANIF MD SAAD, MOHD JAILANI MOHD NOR, KOH WEI KIAT

Driving simulator provides a safe and cost-effective means of testing driver's driving performance. This paper presents the design and development of an economical computer based driving simulator. The simulator developed consists of an online vehicle simulation, actuating systems and visual systems reproducing driving environment scenes. The systems regenerate simulated vehicle dynamics based on computed displacement output value of selectable road profile input. It was used by the automotive research group at Universiti Kebangsaan Malaysia (UKM) to study rider's comfort in cars with selected system parameters.