DESIGN OF JOINTOBJECTIVE QUESTIONS (FOR GATE, IES & IAS) PREVIO...

1. Design of Joint

Objective Questions (For GATE, IES & IAS)

Previous 20-Years GATE Questions

GATE-1.

Square key of side "d/4" each and length

l

is used to transmit torque "T"

from the shaft of diameter "d" to the hub of a pulley. Assuming the length

of the key to be equal to the thickness of the pulley, the average shear

stress developed in the key is given by

[GATE-2003]

4T

16T

8T

16T

(a)

(b)

(c)

(d)

2

2

3

ld

ld

ld

π

d

GATE-1. Ans. (c) If a square key of sides d/4 is used then. In that case, for shear failure we

⎛

× τ

⎞

=

have

d

l

_x

d

T

⎜

⎟

4

2

⎝

⎠

or

8T

x

2

τ =

ld

[Where

τ

_x

is the yield stress in shear and

l

is the key length.]

GATE-2.

A key connecting a flange coupling to a shaft is likely to fail in[GATE-1995]

(a) Shear

(b) tension

(c) torsion

(d) bending

GATE-2. Ans. (a) Shear is the dominant stress on the key

Welded joints

GATE-3.

A 60 mm long and 6 mm thick fillet weld carries a steady load of 15 kN

along the weld. The shear strength of the weld material is equal to 200

MPa. The factor of safety is

[GATE-2006]

(a) 2.4

(b) 3.4

(c) 4.8

(d) 6.8

GATE-3. Ans. (b)

Strength of material

=

Factorofsafety

Actual load or strength on material

Design of Joint

S K Mondal’s

Chapter 1

200(in MPa)

200(in MPa)

3.4

=

=

₃