Appendix 2 Calculations of moment of inertia
- Appendix 2-3 -
2. Moment of inertia of circular cylinder
Approximate values of moment of
inertia of circular cylinder can be
calculated from the graph on the
right.
The top graph is applied to
aluminum (specific gravity 2.7) and
the bottom graph, to steel (specific
gravity 7.85).
(Example)
Material: Aluminum
Outside diameter: 100mm
Length: 7mm
Shape: Circular cylinder
Outside diameter: 100mm
Since the outside diameter is
100mm, the radius is 50mm.
Based on the top graph, moment of
inertia is about 1.9 x 10-4 kgm
2
.
(Calculated value: 0.000186kgm
2
)
Radius
Length
1000
100
10
1
0.1
0.01
0.001
10
-4
10
-5
10
-6
10
100
1000
20
30
50 70
200 300
500 700
Moment of inertia (Specific gravity 2.7)
Moment of inertia (kgm
2
)
Radius R(mm)
Length (mm)
1000
100
10
1
1000
100
10
1
0.1
0.01
0.001
10
-4
10
-5
10
-6
10
100
1000
20
30
50 70
200 300
500 700
Moment of inertia (Specific gravity 7.85)
Moment of inertia (kgm
2
)
Radius R (mm)
Length (mm)
1000
100
10
1
