Project ForgeMachine Design
Design Against Static Load
GATE 2010
Hard
A band brake having band-width of 80 mm, drum diameter of 250 mm, coefficient of friction of 0.25 and angle of wrap of 270 degrees is required to exert a friction torque of 1000 N·m. The maximum tension (in kN) developed in the band is
- A1.88
- B3.56
- C6.12
- 11.56
Explanation
θ=270°=4.712 rad. T1/T2=e^(μθ)=e^(0.25×4.712)=e^1.178≈3.248. Torque=(T1-T2)R=1000 N·m, R=0.125m ⟹ T1-T2=8000N. With T1=3.248T2: 2.248T2=8000 ⟹ T2≈3558N, T1≈11556N≈11.56kN.
Source: GATE ME 2010 (2010)
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