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C1107 Pages 3

PART ட்‌
Answer any two full questions, each carries20 marks.

At a point in a strained material a direct tensile stress of 70 N/mm? and a direct
compressive stress of 50 N/mm? are acting on planes at right angles to each
other. If the maximum principal stress is limited to 75 N/mm‘? tensile,
determine the shear stress that may be allowed on these planes. Also determine
the 1) minimum principal stress ii) maximum shear stress and 111) direction of
principal planes.

A solid shaft of 200 mm diameter has the same cross sectional area as that of a
hollow shaft of the same material with inside diameter of 150 mm. Find the
ratio of the power transmitted by the two shafts at the same speed.

A thin cylinder of internal diameter 2 m contains a fluid at an internal pressure
of 3 N/mm?. Determine the maximum thickness of the cylinder if i) the
longitudinal stress is not to exceed 30 N/mm? and ii) the hoop stress is not to
exceed 40 N/mm’.

Write down Mohr’s theorems for slope and deflection of beams.

A cantilever beam is 2 m long and has a flexural rigidity of 25MN-m‘. It carries
a point load of 3 kN at mid length and a 1.0.101 2 kKN/m along its entire length.
Calculate the deflection and slope at the free end by Macaulay’s method.

What is meant by kern of a section? Sketch the kern of i) circular and ii) square
sections.

A hollow rectangular cast iron column having outside width and depth 250x500
mm and thickness 20 mm is fixed at one end and hinged at the other end.
Length of the column is 8 m. Calculate the safe load that can be applied on the
column assuming a factor of safety of 4. Use Rankine’s theory. Take ൨ =1/1600
and ‏ےہ‎ =600 N/mm?.Compare the value by Euler’s theory. Take E= 95 kN/mm?

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