Contents of Journal of Mechanical Engineering 57, 5 (2006)

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ŠTIGLER, J.: Tee junction as a pipeline net element. Part 1.
A new mathematical model                                                249

ŠTIGLER, J.: Tee junction as a pipeline net element. Part 2.
Coefficients determination                                              263

SINGH, S., MAHESHWARI, S., DEY, A.: Electrical Discharge
Machining (EDM) of aluminium metal matrix composites using
powder-suspended dielectric fluid                                       271

KADRY, S.: Generalization of probabilistic transformation
method for solving random differential equations                        291

MOCHNACKI, B., PAWLAK, E.: Micro/macro models of crystallization
process - comparison of the results of numerical simulations            300

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Abstracts

Tee junction as a pipeline net element. Part 1. A new mathematical model

JAROSLAV ŠTIGLER

The problem of mathematical model of the tee junction is divided into two parts. The first part is theoretical. It is focused on the derivation of a new mathematical model of the tee junction as a pipeline net element. New loss coefficients, which describe fluid flow in the tee junction, are introduced. The mathematical model is derived for the unsteady incompressible fluid flow.

Tee junction as a pipeline net element. Part 2. Coefficients determination

JAROSLAV ŠTIGLER

A new mathematical model of the tee junction has been established in Part 1. In Part 2, the attention is focused on the numerical experiment of turbulent fluid flow in the tee junction. Domain size and loss coefficients of the tee junction are determined on the basis of numerical experiment.

Electrical Discharge Machining (EDM) of aluminium metal matrix composites using powder-suspended dielectric fluid

SHANKAR SINGH, SACHIN MAHESHWARI, ALOKE DEY

Aluminium Metal Matrix Composites (AMMCs), owing to their better multiple functional characteristics, find a vast range of applications in the aerospace, automobiles, defence, sports and tools industries. These materials pose a greater challenge to manufacturing engineers due to the constraints in traditional machining to form complex shapes and achieve fine surface finish because of their abrasive reinforcements, high hardness and brittleness.

This paper reports experimental investigations of the effect of process parameters on the performance measures, namely Material Removal Rate (MRR) and surface roughness, via a hybrid manufacturing process Abrasive Electrical Discharge Machining (AEDM) involving the interaction of mechanical abrasion and thermal process, on stir-casted 6061Al/Al2O3p/20p work specimens with copper electrode and SiC abrasive powder-suspended dielectric fluid. A mixed orthogonal array L18 (21´ 37) experimental design was chosen to identify the effect of seven control factors viz. pulse current (Ip), pulse ON time (T ON), duty cycle (t), gap voltage (Vg), tool electrode lift time (TL), Abrasive Powder Concentration (APC) and Abrasive Particle Size (APS) with three levels each, and a noise factor, aspect ratio having two levels.

An attempt has been made to develop models for optimizing AEDM characteristics, and the significance of the models was checked using the Analysis of Variance (ANOVA) technique and F-tests. The experimental results have shown that MRR and the surface roughness increased with an increase in the addition of abrasives into the dielectric fluid.