Third year, Department of Mechanical Engineering
First and second Units Questions.
Answer ALL
Questions PART A – (10 x 2 = 20 Marks)
1)What
are the various phases of design process.
2) Write down different factors influencing machine
design
3) Define torsional stress
4)
Differentiate between impact and shock loading
5) What is mean by eccentric loading
6) Describe material properties hardness,
stiffness and resilience.
7) Define stress concentration factor
8)
Compare straight beam and curved beam.
9.Define
bending stress.
10.Define
fit and its types.
PART – B(
5×13=65 Marks) Answer all questions
1.A
mild steel bracket as shown in the figure.It is subjected to a pull of 6000N
acting at 45 to its horizontal axis.The bracket has a rectangular section whose
depth is twice the thickness.Find the cross sectional dimensions of the
bracket,if the permissible stress in the material of the bracket is limited to
60 MPa. (16)
2)
A Cantilever of span 500
mm carries a vertical downward load of 6 KN at free end. Assume yield value of
350 Mpa and factor of safety of 3. Find the economical section for the
cantilever among a) Circular cross section of diameter “d”b) Rectangular section of depth “h” and
width “t” with h/t =2. c) I section of
depth 7t and flange width 5t where t is thickness. Specify the dimension and
cross sectional area . (16)
3.C-clamp is to bear the force F applied onto it. It has T-section
shown in figure .If the maximum tensile stress in the clamp is limited to 130
Mpa.Find ‘ F’ (16)
4) A crane hook has a
section shown in figure which for the purpose of analysis is considered
tapezoidal shown in figure.It is made of the plain carbon steel with an yield
strength of 380Mpa in Tension.Determine the load capacity of thehook for a
factor of safety of 3
5) i) A simply supported shaft 30 mm diameter and 200mm long
is acted upon by a sudden load of 1000 N at its mid span.this load falls freely
from a height of 2mm. find the impact strees produced in the shaft.Assume
young’s modulus of the shaft material as 2´105Mpa. (8)
ii)A cantilever of a span 250 mm and 50mm diameter carries a
vertical downward load of 3 kN at free end along with a torque of 1000N-m and an
axial pull of 15kN.calculate the maximum normal stress at the top and bottom
face of the fixed end.(8)
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