| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程研究所 === 83 === The major object of this paper is to solve the three
dimensional steady-state deformation problems of the strip in
the symmetrical rolling process ,under the assumption that
the rolls are perfectly rigid. The rigid plastic finite element
method is used in developing the numerical analysis model. The
material is divided into 8-node hexahedral isoparametric
elements during the steady-state deformation in the rolling
analysis. The nodal velocities that minimize the functional
are obtained by assuming that the plate is composed of a rigid
plastic material and the thickness is uniform. The
distributions of the velocity and the equivalent strain rate in
the whole region are calaulated from the obtained nodal
velocities. From the velocity field and the boundary
conditions, the streamlines are constructed, and the thickness
distribution of the plate is estimated by integrating the
velocity of the surface along the streamlines. The distribution
of equivalent strain is given by integrating the equivalent
strain rate along the streamlines, and then,the distribution is
converted into that of flow stress by the use of the flow
curve. A new finite element mesh is generated by assuming the
streamlines to be element boundaries. The nodal velocities that
minimize the functional are calculated again for the so-
determined finite element mesh and flow stress distribution.
Repeat above procedures until the calculated result converges,
the analytical results of the steady-state deformation will be
obtained. According to the above mentioned concept, this paper
will develop a numerical analysis model to discuss the
deformation behavior,including the geometry of rolled product,
the distribution of strain rate and rolling force ,etc. In
order to verify the availability of the developed numerical
analysis model,the data of references and the results of
experiment are compared with the analytical answers.
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