Dear list members,
I am looking for help in explaining a strange results
during a FE simulation.
I performed a FE simulation of a punch and bulge test,
which involves all three nonlinearities: elastic-plastic
behaviour(pure plasticity),contact modelling with friction,
large strain analysis. The FE solver I used is
ABAQUS/STANDARD V5.7-6
Brief description of the simulation:
The FE model consists of a rigid punch, a support round
rigid die with a hole of a suitable diameter and a piece of
thin circular plate. The plate is placed on the die and is
pressed down by the punch at the centre,by a distance,
i.e a few millimeters. For simulation of this test,
axisymmetric solid elements, CAX4R were used. There were
two contact areas: the contact between the punch and the
plate and the contact between the die and the plate.
The simulation was successfully completed. However the
results looks strange in two points:
1. The Mises stresses reach the yield stress over almost
all area of the plate (on the cross section along the
radial direction) even in the area of free curl-up
end of the plate, except a very small area around the
contact area with the die;
2. The contour plot of the Mises is inconsistent with that
of equivalent plastic strain (PEEQ)in that in the PEEQ
plot, there were a relative small plastic deformation area
around the contact point with the punch (about one fifth of
the radius of the plate)with zero or very small plastic
deformation over other area (this looks realistic), though
in the Mises plot, Mises stresses over most area reached
the yield stress.
I would appreciate greatly if you could explain these
results or the cause for these results. I am also wondering
if it is possible for these results to result from the
simulation itself, i.e inappropriate definition of
the input deck.
Many thanks in advance.
Wei
---------------------
Wei LI, Room 207
Dept. of Mech. Eng.
Liverpool University
Liverpool, L69 3BX
Tel:0151-794 4931
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