1
s
b
2
3
1
NJ
50B
2
4.1
45
45
M
M
4.1
1
M −ϕ
M
ϕ
4.2
,
4.3 a
4.3 b
4.3
c
τs =
Wp =
3M s
4W p
(4.1)
π d3
16
M
M
o
o
4.2
4.3
2
Mb
τb =
3M b
4W p
(4.2)
τb =
Mb
Wp
(4.3)
1
WP
2
3
4
5
Ms
ϕs
Mb
6
7
3
ϕb
ϕb
1
τs =
3M s
4W p
2
τb =
3M b
4W p
τb =
3
Wp =
π d3
16
Mb
Wp
mm3
N m
4
1
2
3
4
45
4
MPa