## GATE ME solved Questions on Design of clutch and spring (Machine Design)

**Question #1**

A single – plate clutch has a friction disc with inner and outer radii of 20mm and 40 mm, respectively. The friction lining in the disc is made in such a way that the coefficient of friction μ varies radially as μ=0.01r, where r is in mm. The clutch needs to transmit a friction torque of 18.85kN.mm. As per uniform pressure theory, the pressure (in MPa) on the disc is _________

**[GATE 2017 Set 2, 2 marks]**

**Question #2**

A disc clutch with a single friction surface has coefficient of friction equal to 0.3. The maximum pressure which can be imposed on the friction material is 1.5 MPa. The outer diameter of the clutch plate is 200 mm and its internal diameter is 100 mm. Assuming uniform wear theory for the clutch plate, the maximum torque (in N.m) that can be transmitted is _________

**[GATE ME 2014 Set 2, 2 marks]**

**Question #3**

A clutch has outer and inner diameters 100 mm and 40 mm respectively. Assuming a uniform pressure of 2 MPa and coefficient of friction of liner material is 0.4, the torque carrying capacity of the clutch is

**[GATE 2008, 2 marks]**

(A) 148 Nm

(B) 196 Nm

(C) 372 Nm

(D) 490 Nm

**Question #4**

A disk clutch is required to transmit 5 kW at 2000 rpm. The disk has a friction lining with coefficient of friction equal to 0.25. bore radius of friction lining is equal to 25 mm. assume uniform contact pressure of 1 MPa. The value of outside radius of the friction lining is:

(A) 39.4 mm

(B) 49.5 mm

(C) 97.9 mm

(D) 142.9 mm

**[GATE 2006,2 marks]**

## GATE ME solve Questions on Design of Springs (Machine Design)

**Question #1**

If the wire diameter of a compressive helical spring is increased by 2%, the change in spring stiffness (in %) is _____ (correct to two decimal places).

**[GATE 2018 Set 1, 1 mark]**

**Question #2**

A helical compression spring made of wire of circular cross-section is subjected to a compressive load. The maximum shear stress induced in the cross-section of the wire is 24 MPa. For the same compressive load, if both the wire diameter and the mean coil diameter are doubled, the maximum shear stress (in MPa) induced in the cross-section of the wire is _____.

**[GATE 2017 Set 2, 2 marks]**

**Question #3**

The spring constant of a helical compression spring DOES NOT depend on

(A) coil diameter

(B) material strength

(C) number of active turns

(D) wire diameter

**[GATE 2016 Set 1, 1 mark ]**

**Question #4**

A compression spring is made of music wire of 20 mm diameter having a shear strength and shear modulus of 800 Mpa and 80 GPa respectively. The mean coil diameter is 20 mm, free length is 400 mm and the number of active coils is 10. If the mean coul diameter is reduced to 10 mm , the stiffness of the spring is approximately

(A) Decreased by8 times

(B) Decreased by 2 times

(C)Increased by 2 times

(D) Increased by 8 times

**[GATE 2008, 2 marks]**

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