GATE ME Solved questions on Design of Brakes(Machine Design)

Question #1

The schematic of an external drum rotating clockwise engaging with a short shoe is shown in the figure. The shoe is mounted at point Y on a rigid lever XYZ hinged at point X. A force F = 100 N is applied at the free end of the lever as shown. Given that the coefficient of friction between the shoe and the drum is 0.3, the braking torque (in Nm) applied on the drum is ____ (correct to two decimal places).

[GATE 2018 Set1, 2 marks]

Question #2

The forces F1 and F2 in a brake band and the direction of rotation of the drum are as shown in the figure. The coefficient of friction is 0.25. The angle of wrap is $3\pi /2$ radians. It is given that R = 1 m and F2 = 1 N. The torque (in N-m) exerted on the drum is _________

[GATE 2016,Set 2, 1 mark]

Question #3

For the brake shown in the figure, which one of the following is TRUE?
(A) Self energizing for clockwise rotation of the drum
(B) Self energizing for anti-clockwise rotation of the drum
(C) Self energizing for rotation in either direction of the drum
(D) Not of the self energizing type

[GATE 2016,Set 2, 1 mark]

Question #4

A mass of 2000 kg is currently being lowered at a velocity of 2 m/s from the drum as shown in the figure. The mass moment of inertia of the drum is 150 kg-m2. On applying the brake, the mass is brought to rest in a distance of 0.5 m. The energy absorbed by the brake (in kJ) is __________

[GATE 2016 Set 2, 2 marks]

Question #5

A drum brake is shown in the figure. The drum is rotating in anticlockwise direction. The coefficient of friction between drum and shoe is 0.2. The dimensions shown in the figure are in mm. The braking torque (in N.m) for the brake shoe is _______

[GATE 2014 Set 3, 2 marks]

Question #6

A force of 400 N is applied to the brake drum of 0.5 m diameter in a band-brake system as shown in the figure, where the wrapping angle is 180°. If the coefficient of friction between the drum and the band is 0.25, the braking torque applied, in N.m is

(A) 100.6

(B) 54.4

(C) 22.1

(D) 15.7

[GATE 2012, 2 marks]

Question #7

A band brake having width of 80 m, drum diameter of 250 mm, coefficient of friction 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

(A) 1.88

(B) 3.56

(C) 6.12

(D) 11.56

[GATE 2010, 2 marks]

Question #8

A block brake shown below has a face width of 300 mm and a mean coefficient of friction of 0.25. For an activating force of 400 N, the braking torque in N-m is

(A) 30

(B) 40

(C) 45

(D) 60

[GATE 2007, 2 marks]