PTU Punjab Technical University B-Tech May 2019 Question Papers 3rd Semester May Marine Engineering
Total No. of Pages : 03
Total No. of Questions : 09
B.Tech.(Marine Engg.) (2013 Onwards)/
B.Tech.(ME) (2011 Onwards)
(Sem.?3)
STRENGTH OF MATERIALS ? I
Subject Code : BTME-301
M.Code : 59111
Time : 3 Hrs. Max. Marks : 60
INSTRUCTIONS TO CANDIDATES :
1.
SECTION-A is COMPULSORY consisting of TEN questions carrying T WO marks
each.
2.
SECTION-B contains FIVE questions carrying FIVE marks each and students
have to attempt any FOUR questions.
3.
SECTION-C contains T HREE questions carrying T EN marks each and students
have to attempt any T WO questions.
SECTION-A
1.
Answer briefly :
a. Define yield stress.
b. Explain the significance of modulus of rigidity.
c. What are principal planes?
d. What do you mean by point of contraflexure?
e. What is a flitched beam?
f. Discuss the factors affecting flexural rigidity of a beam.
g. Why a hollow shaft is preferred over a solid shaft?
h. What is the equivalent length of a column?
i. Differentiate between a column and a strut.
j. A cantilever beam carries a load `W', which is distributed uniformly over its entire
length. If the same load is placed at the free end of the same cantilever, then what will
be the ratio of maximum deflection in the first case to that in the second case?
1 | M-59111
(S2)-39
SECTION-B
2.
Explain :
(a) Factor of safety and its significance.
(b) Slenderness ratio and its significance.
3.
A square bar of 25 mm side is held between two rigid plates and loaded by an axial pull `P'
equals to 300 kN, as shown in Fig. 1. Determine the reactions offered by supports A. Take
E = 200 GPa.
A
B
C
P
400 mm
250 mm
Fig.1
4.
Determine the diameters of a hollow shaft transmitting 300 kW at 250 rpm. The maximum
shear stress in the shaft should not exceed 30 MPa. Assume the ratio of inner to outer
diameter (di/do) = 0.75and modulus of rigidity (C) = 100 GPa.
5.
Find the Euler's crippling load for a hollow cylindrical cast iron (E = 80GPa) column
having 150mm external diameter and 20 mm thickness. The column is 6 m long and hinged
at both ends.
6.
The mid span deflection of a simply supported beam (span = 5m) loaded with a
concentrated load 20kN at the centre, is 2.5 mm. Determine the maximum deflection if the
concentrated load is replaced by a UDL of intensity 4 kN/m acting over the whole span of
the beam.
SECTION-C
7.
The state of stress on an element is shown in Fig. 2. Determine the magnitudes and
directions of principal stresses and also the greatest shear stress. Show all the results on
properly oriented planes.
2 | M-59111
(S2)-39
10 MPa
30 MPa
10 MPa
Fig. 2
Fig. 2
8.
Draw shear force and bending moment diagrams for the beam loaded in Fig. 3. Label the
salient points.
30 kN
20 kN/m
20 kN
A
B
C
D
E
F
2m
2m
4m
2m
2m
Fig. 3
M
E
9.
Stating the assumptions made, derive the complete flexural formula :
.
I
y
r
NA
The symbols have their usual meaning.
NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
3 | M-59111
(S2)-39
This post was last modified on 04 November 2019