الفهرس 
ABSTRACT
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Abstract
Previous research has shown that deep drawing of sheet metals through conical or tractrix dies resulted in significant improvement in the limiting drawing ratio together with a significant decrease in drawing load. Moreover, blank-holder is eliminated meaning simplification of equipment.
In this study a novel deep drawing process is introduced for producing elliptic cups using a conical die without blank holder or draw beads. In this technique an elliptical-cup is produced by pushing a circular blank using a flat-headed elliptic punch through a conical die with an elliptic aperture in a single stroke. The introduced process parameters have been theoretically simulated and experimentally varified. As a first step toward optimazation, finite element analysis using ANSYS APDL has been applied to optimize setup and tooling design. Setup parameters such as die half-cone angle, die fillet radius, die aperture length, and punch fillet radius have been optimized. Moreover process parameters such as clearance ratio, blank thickness and friction on punch-blank and die-blank interfaces have been investigated. Optimization showed that, a die with a half cone angle of 18° has shown the best drawability for the new technique. Numerical investigations for brass (CuZn33) and commercially pure hard aluminum blanks were performed using ANSYS APDL and Deform-3D softwares respectively.
A single die with a major diameter of 60 mm and an aspect ratio of 2 has been designed and manufactured together with seven punches having aspect ratios ranging from 2 to 2.25. Tensile tests were carried out to obtain the stress-strain behavior for the used materials. Brass sheets (CuZn33) with initial thicknesses of 1.5, 1.9, 2.4, 3 and 3.2 mm and commercially pure hard aluminum sheet metal blanks with initial thicknesses of 1.5, 1.75, 1.9, 2.75 and 3 mm at different clearance ratios have been used in experimentation. The effects of blank thickness and clearance ratio on limiting drawing ratio, drawing load, thickness strain, produced cup height and modes of failure were experimentally investigated. Brass elliptic cups with a limiting drawing ratio (LDR) of 2.26 have been successfully achieved. Hard aluminum elliptic cups with a limiting drawing ratio, LDR of 2.57 have been successfully achieved. These LDRs are significantly higher than those obtained by conventional techniques and very close to those obtained with complicated non- conventional techniques.
Finite element model results showed good agreement with experimental results for punch load, cup thickness and uniformity and modes of failure. This agreement proves the validity of the proposed model for simulating the proposed technique.
Experimentation showed that blank thicknesses between 1.9 and 3 mm for brass and between 2.75 and 3 mm for hard aluminum are most suitable for the present technique.