Page 70 - E-modul_Mekanika Teknik 2_SMK_Kelas X

3
MOMEN KELEMBAMAN/INERSIA

Jarak Z1 dan Z2 terhadap sumbu x dan y adalah:
b1 = 5 cm – 1 cm = 4 cm
b2 = 0 cm
b3 = 5 cm – 1 cm = 4 cm
a1 = 5 cm – 3 cm = 2 cm
a2 = 0 cm
a3 = 5 cm – 3 cm = 2 cm
Momen kelembaman/Inersia terhadap sumbu x:
Rumus : Ix = I2x + Fb 2
4
2
4
2
3
Ix1 = 1/12 . 6 cm . (2 cm) + 12 cm . (4 cm) = 4 cm + 192 cm = 196 cm 4
2
3
4
Ix2 = 1/12 . 2 cm . (6 cm) + 12 cm . (0 cm) = 36 cm + 0 cm = 36 cm 4
2
4
4
3
Ix3 = 1/12 . 6 cm . (2 cm) + 12 cm . (4 cm) = 4 cm + 192 cm = 196 cm 4
2
2
4
4
Jadi Ix = 428 cm
Momen kelembaman/Inersia terhadap sumbu y:
Rumus : Iy = I2y + F.a 2
2
3
4
Iy1 = 1/12 . 2 cm . (6 cm) + 12 cm . (2 cm) = 36 cm + 48 cm = 84 cm 4
2
4
4
4
4
2
3
Iy2 = 1/12 . 6 cm . (2 cm) + 12 cm . (0 cm) = 4 cm + 0 cm = 4 cm
2
Iy3 = 1/12 . 2 cm . (6 cm) + 12 cm . (2 cm) = 36 cm + 48 cm = 84 cm 4
4
3
2
2
4
Jadi Iy = 172 cm 4

58