B3B032 Total Pages:2

(b) A 300 mm x 160 mm rolled steel joist of I section has flanges 11 mm thick and web

8 mm thick. Find the safe uniformly distributed load that the section will carry over a

span of 5 m if the permissible stress is limited to 120 N/mm/?. (7.5)
. Derive the expression for shearing stress in a beam section stating the assumptions
made (15)
PART ^

(Answer any two questions)

. (a) Explain principal planes and principal stresses (5)
(b) A point is subjected to a tensile stress of 60 N/mm? and a compressive stress of 40

N/mm’, acting on two mutually perpendicular planes. A shear stress of 10 N/mm 21६
also acting on these planes. Determine the principal stresses and the maximum shear
stress. (15)

. Select a suitable diameter of a solid shaft of circular section to transmit 112.5 kW of
power at 200 r.p.m., if the allowable shear stress is 75 N/mm 2 and the allowable twist
is 1° in a length of 3 m. Take © as 0.82 x 10° N/mm’. (20)

. (a) What are the assumptions in Euler’s column theory. (5)

(b) Write the equations for Euler’s crippling load for columns with both ends hinged,

both ends fixed, one end fixed and the other hinged, one end fixed and the other free.

(5)

(c) A hollow alloy tube 5 m long with diameters 40 mm and 25 mm was found to
extent 6.4 mm under a tensile load of 60 KN. Find the buckling load for the tube when

used as a strut with both ends pinned. (10)

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