The Delft Sand, Clay & Rock Cutting Model, 2019a

The Delft Sand, Clay & Rock Cutting Model.
2
A x B x C
0
2
B B 4 A
C
a
h
hb,m
x with: rm
2
A c
h
b,m
i
a cos
sin
2
A
sin
(7-102)
1
a 2
c
B
sin
sin
h
i
1
c
cos
C hi
h
sin sin
The following criteria are valid for the use of this method.
i
if h
if h
h then use h
b,m b b,m
h then use h
b,m b b,m
(7-103)
To see which solution is valid, the terms of the equation have to be analyzed. For α+β0 and Cπ/2 the term A0 because of the minus sign. This will only result in a positive
solution if the – sign is applied. So at small blade angles the plus sign gives the correct solution, while large blade
angles require the minus sign solution.
Figure 7-35, Figure 7-36 and Figure 7-37 show the shear angle and the horizontal cutting force coefficient and the
vertical cutting force coefficient for the Curling Type. At large blade angles, both the horizontal and vertical
forces become very large. In cases of large blade angles the Curling Type will hardly occur because the Flow
Type results in smaller forces.
sin
sin
sin sin
rm
sin sin
F c h w c h w
h s i s i HC
cos cos
rm
sin sin
F
c h w c h w
s i s i VC
(7-104)
(7-105)
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