Andhra University 2008 B.E STRENGTH OF MATERIALS - exam paper

STRENGTH OF MATERIALS

Chemical Engineering

Time : 3 hours Maximum : 75 Marks

ques. one is compulsory

ans any 4 from ques. two to 8

All ques. carry marks

20

b) A 0.12 mm diameter steel rod AB is fitted to a round hole

near end C of the wooden member CD. For the loading

shown, determine the maximum avg. normal stress in tbe

wood (Figure 2) (8 Marks)

Q.3

The five kN load P is supported by 2 wooden members of

uniform cross part that are joined by the simple glue.

Determine the normal and shearing stresses in the glued surface

(Figure 3) (15 Marks)

Q.4

For the beam and loading shown, draw the Shear force and

Bending moment diagrams (Figure 4) (7 Marks)

b) Draw the Shear force Diagram and Bending moment

diagrams for the beam loaded as shown. (Figure 5)


(8 Marks)

(Figure 3)

21

Q.5

a) The assembly shown consists of an aluminium shell with

(Ea=70GPa,aa=23.6 ´ 10-6/ 0C) fully bonded to a steel

core (Es=200GPa,as=11.7 ´ 10-6/ 0C) and is unstress

-ed at temperature 200C. Considering only axial deformations,

determine the stress in the aluminium shell when the temperature

reaches 1800C. (Figure 6)


b) The 1.5 m concrete post is reinforced with 6 steel bars, every

with a 28-mm diameter. provided that ES = 200 GPa, and

EC = 25 GPa, determine the normal stresses in the steel and in

the concrete when a 1550 kN axial centric force P is applied to

the post (Figure 7)

(Figure 5)

22

Q.6

a) The torques shown are exerted on pulleys A,B,C. The shafts

are solid. Determine the maximum shearing stress in a) Shaft

AB and b) Shaft BC (Figure 8)

b) The allowable shearing stress is 100 MPa in the 36-mm diameter

part AB and 60 MPa in the 40-mm diameter part BC.

Neglecting the effect of stress concentrations, determine the

largest torque that can be applied at A.(Figure 9)


23

Q.7

At a point in a strained material the vertical shear stress is 15

MPa and the horizontal tensile stress is 25 MPa. Using Mohr’s

circle method obtain the principal stresses and direction of the

principal of the principal planes (15 Marks)

Q.8

a) A safety value of eight cm diameter is to blow off at a pressure of 1

N/mm2 gauge. It is held by a closed coil helical spring of circular

steel wire. The mean diameter is 15 cm and the initial compression

is 2cm. obtain the diameter of the steel wire and the number of

coils necessary if the shear stress allowed is 80 N/mm2.

(5 Marks)

b) A thin spherical shell 50 cm in diameter with a thickness three mm is

full of water at atmospheric pressure (0.1 MPa). obtain the intensity

of radial pressure exerted on the wall of the shell if 30 cc of

water at atmospheric pressure is pumped into the shell. compute


the resulting hoop stress and the change in quantity of sphere if E

= 210 GPa, m=0.33,Kwater=2.361GPa (10 Marks)

Earning:   Approval pending.