Civil Engineering Reference
In-Depth Information
The maximum forging force is a more interesting objective function (or constraint). Actually, the press
capacity is limited and the reduction of the required force can make it possible to forge the part using a
lower capacity press. This can also help to decide whether the number of forging operations can be
reduced or not.
m
1
˙
h
MAX
t
q
1
K
(
3
)
d
K
v
t
ds
max
(5.42)
t
c
t
-------------------------------------------------------------------------------------------------------
V
die ,
t
where
V
die,
t
is the generalized tool velocity at time
t
.
To o l We a r
For mass production, the tool wear can be a critical criterion, because the tool life has a direct influence
on the production costs. For abrasive wear, the following objective function can be suggested [Fel89]:
t
t
end
wear
K
wear
v
t
n
d
td
(5.43)
t
t
0
die
where
K
wear
is a wear coefficient, and
n
is the normal stress.
Folding Defects
During the first stages of the design process, avoiding folding defects are probably the main concern of
the designer. The corresponding objective function (or design constraint) can be derived from the distance
I
fold
x
des
x
()
d
(5.44)
where
des
(
x
) is the projection of any point
x
on
∂
des
.
FIGURE 5.25
At the end of the simulation, as a result of a folding defect, a part of the boundary is not in contact
with the desired shape.
