الفهرس 
Chapter One: Introduction and literature SurveyOnly 14 pages are availabe for public view
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Abstract
Nosing is a process in which the tube is formed by forcing a punch (axial pressing) into the tube end with the die, and then retracting the punch back off after achieving the desired shape in industrial operations. A theoretical modeling is adopted to analyze relevant parameters for improving forming process.
In this work, Theoretical analysis, both mathematically and numerically using finite element method (FEM), is used to model the cold nosing process of aluminum tubes using conical and hemispherical dies. A mathematical model is proposed for predicting the forming load, tube wall thickness change and strain distribution. This model was based on the techniques of energy method for obtaining the nosing load and thickness and strain distributions. from this model, load-displacement curves, thickness distribution and strain distribution at different nosing process parameters were obtained. The influence of the nosing process parameters, namely tube wall thickness (t), conical semi-die angle (α), coefficient of friction (μ) and die shape studied on the deformation mode, critical nosing ratios of formed tubes, thickness, strain distributions and mode of failure. All of these were checked using the finite element analysis.
The experimental work was carried out on commercial - purity aluminum tubes with outer diameter of 48 mm, length of 55 mm and various tube wall thickness 1, 1.5, 2, 2.5, 3, 3.5 mm. Two different dies were used. Conical die with semi-angles (15, 30, 45, 60˚) and hemispherical die with an inner diameter of 48.2 mm. Friction condition in the experimental work were dry and lubricated (grease and PTFE) conditions with coefficient of frictions 0.15, 0.05 and 0.04 respectively.
Design and modifying tool and punch design were introduced. The design included a front plunger to be inserted inside the original tube to enhance axially. Design and modifying an outer sleeve was also used constraining the tube to eliminate bulging. The experimental results presented in nosing load - punch displacement curves, thickness distribution and strain distribution. Modes of failure were examined. Experimental results verified the trends of the theoretical analysis. Comparison between theoretical and FE predictions to the experimental results showed a good agreement.