undefined

DR. BABASAHEB AMBEDKAR TECHNOLOGICAL UNIVERSITY, LONERE

Semester Examination – MAY - 2019

------------------------------------------------------------------------------------------------------

-

Branch: SY Mechanical Engineering

Sem.: IV

Subject with Subject Code: SOM (BTMEC403)

Date: 20-05-2019

Marks: 60

Time: 3 Hr.

=

===========================================================

Instructions to the Students

1

2

3

4

. Each question carries 12 marks.

. Attempt any five questions of the following.

. Illustrate your answers with neat sketches, diagram etc., wherever necessary.

. If some part or parameter is noticed to be missing, you may appropriately

assume it and should mention it clearly

_

____________________________________________________________________

(Marks)

Q.1. a) Define the following terms

i) Young’s Modulus

ii) Modulus of Rigidity

iii) Poisson’s ratio

iv) Factor of safety

v) Hook’s law

(05)

b) Two brass rods and one steel rod together support a load as shown in Fig

2

below. If the stresses in brass and steel are not to exceed 60 N/mm and

2 5

20N/mm , find the safe load that can be supported .Take E for steel = 2 x 10

2 5 2

1

N/mm and for brass = 1 x 10 N/mm . The cross sectional area of steed rod is

1

2

500 mm and of each brass rod is 1000 mm .

(07)

OR

b) A steel rod of 3 cm diameter is enclosed centrally in a hollow copper tube of

external diameter 5 cm and internal diameter of 4 cm. The composite bar is then

subjected to an axial pull of 45000 N. If the length of each bar is equal to

1

5 cm. Determine:

A10D47D351C36413541E38D942438EA1

undefined

i) The stresses in the rod and tube.

ii) Load carried by each bar.

(07)

Q.2. a) Prove that stress induced in a body when the load is applied with the impact

is given by

where P = Load applied with impact, A = Cross-sectional area of the body,

h = height through which load falls, L= Length of the body, and

E = Modulus of elasticity.

(06)

OR

2

a) The maximum stress produced by a pull in a bar of length 1 m is 150 N/mm .

The area of cross-sections and length are shown in Fig. Calculate the strain

5

2

energy stored in the bar if E = 2 x 10 N/mm .

(06)

2

b) The stresses at a point in a bar are 200 N/mm (tensile) and 100 N/mm

compressive). Determine the resultant stress in magnitude and direction on a

plane inclined at 60° to the axis of the major stress. Also determine the

maximum intensity of shear stress in the material at the point. (06)

(

Q.3. a) A hollow rectangular section is having external size 500 mm x 450 mm

internal size 400 mm x 350 mm. It carries a vertical load of 100 kN at outer

edge of the column on X-axis. Calculate maximum and minimum intensities of

stresses in the section. Assume 500 mm side horizontal.

(06)

b) Draw the shear force and bending moment (B.M.) diagram for a simply

supported beam of length 9 m and carrying a uniformly distributed load of

1

0 kN/m for a distance of 6 m from the left end. Also calculate the maximum

B.M. on the section.

(06)

A10D47D351C36413541E38D942438EA1

undefined

Q.4.

(12)

Q.5. a)

(

05)

OR

a)

b)

(

(07)

Q.6. a)

A10D47D351C36413541E38D942438EA1

undefined

J = Polar moment of inertia,

τ = Max. Shear stress,

R= Radius of the shaft,

C = Modulus rigidity,

θ = Angle of twist, and

L = Length of the shaft.

(06)

b) A hollow shaft, having an inside diameter 60% of its outer diameter, is to

replace a solid shaft transmitting the same power at the same speed. Calculate

the percentage saving in material, if the material to be used is also the same.

(06)

OR

b) A solid round bar 4 m long and 5 cm in diameter was found to extend

.6 mm under a tensile load of 50 kN. This bar is used as a strut with both ends

hinged. Determine the buckling load for the bar and also the safe load taking

factor of safety as 4. (06)

4

A10D47D351C36413541E38D942438EA1