الفهرس 
LITERATURE SURVEYOnly 14 pages are availabe for public view
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Abstract
The stress distribution in punching dies has not been investigated either
experimentally or theoretically. As a result, the die design has -so far- been
based upon experience. The present work is devoted to study the stress
distributions in punching dies by the application of the finite element
teclmique. For this sake, a finite element software capable to handle linear
elastostatic problems was established. In addition, some supplementary
programs were prepared for pre-processing, and post-processing finite
element solution. The program was tested by comparing the results
computed for some fundamental problems with the corresponding results
obtained from closed forrn solutions. A model was then established to
simulate a punching die block having a circular opening, taking into
consideration the frictional forces, and the thrust forces, as well as the main
cutting forces. The model was verified experimentally. Experiments were
performed to determine the strain distribution on the surface of a punching
die, by using electrical strain gauges. Comparing the experimental results
with the results obtained through the finite element analysis established the
val idity and usefulness of the proposed model. Consequently, the model was
employed to study the stress distributions in punching dies, and the effects
of the die geometry on these distributions. The main results showed that, the
stresses are at its maximum near to the cutting edge, and tend to reduce
sharply beyond the loading zone. The width of the loading zone, as well as
the stock thickness and its shearing strength are the major factors affecting
the values and the distribution of the stresses, while the geometry of the die
affects the value and direction of the radial displacement of the cutting edge.
Increasing the diameter of the opening beneath the die results in increasing
the tangential stress, but it seems that it does not influence both the axial and
the radial stress significantly .