GITAM University 2006 B.E Mechanical Engineering Machine Design - I - Question Paper

College of Engineering
Gandhi Institute of Technology and Management, Visakhapatnam
(Affiliated to Andhra University)

B.E. (Mechanical Engineering)
3rd Year 1st Semester exams 2005-2006
(Autonomous Stream)

Machine Design - I









1. Answer the subsequent (10x2=20)
a) Explain the term resilience.
b) What are the range of percentages of carbon and alloying elements in 15 Ni 13 Cr one Mo 12 Ge.
c) Give any 1 practical application of stress system represented by Mohr’s circle degenerates into a point on positive normal stress axis.
d) What is the relation ranging from the principal stresses and maximum shear stress in a component subjected to torsion.
e) Differentiate ranging from caulking and fullering.
f) What do you mean by bolt of uniform strength.
g) How the joint separation can be prevented in bolted joints.
h) What are the advantages of splined connections over keyed connections.
i) What are the advantages of laminated springs over springs of constant depth.
j) Define the coefficient of steadiness of fly wheel.


PART – B

ans any 4 of the subsequent. If you attempt more than 4 questions, only the 1st 4 in order will be valued.

2. What are the different steps involved in design synthesis? discuss in detail. (10)
3. A round steel bar having Sy= 800 MPa is subjected to loads producing computed stresses of and
a) Sketch Mohr’s circle showing the relative locations of
maximum normal stress and Max. Shear stress.
b) Determine the safety factor with respect to initial
yielding according to the Max. shear stress theory
and according to Max. distortion energy theory. (10)
4. An M24 course pitch (inside diameter is 20.3 mm) tie bolt is 380 mm long ranging from the bolted members. It is tightened to an initial load of 45 KN. presume a coefficient of friction for both the threads and collar of 0.15 and a collar radius of 15 mm, determine.
a) The necessary tightening torque applied to the nut
using the theoretical screw thread torque formula.
b) Determine the maximum shear stress in the bolt. (10)
5. Design a cast iron protective kind flange coupling to connect 2 shafts in order to transmit 12 KW at 500 rpm. The subsequent permissible stresses may be used.
Shear stress for shaft, bolt and key material: 40 MPa Crushing stress for bolt and key: 80 MPa
Shear stress for cast iron : 80 MPa.
(10)5. Design a cast iron protective kind flange coupling to connect 2 shafts in order to transmit 12 KW at 500 rpm. The subsequent permissible stresses may be used.
Shear stress for shaft, bolt and key material: 40 MPa Crushing stress for bolt and key: 80 MPa
Shear stress for cast iron : 80 MPa.
(10)
6. A simple band brake is operated by a lever 500 mm long. The brake drum is of 500 mm dia and the brake band embraces 5 – eighths of its circumference. 1 end of the band is attached to the full crown of the lever, while the other is attached to a pin on the lever, 100 mm from the fulcrum. If the coefficient of friction is 0.25 and the effort applied to the end of the brake lever is 500N. What is the maximum braking torque on the drum? (10)

7. What thickness of leaf is needed for a cantilever leaf spring designed to the subsequent specifications. (10)
Load on the spring = 2000 N
Design stress in tension = 350 MN/m2
Total number of leaves = 8
Length of spring = 500 mm
Width of every leaf = 50 mm
Number of extra full length leaves = 2

8. Design a sleeve and cotter joint to resist a tensile load of 100 KN. All parts of the joint are made of the identical material with the subsequent allowable stresses in tension, shear and crushing as 100 MPa, 60 MPa and 180 MPa respectively. (10)

Earning:   Approval pending.