B B7068

b) A cantilever beam with span 3m and cross section 200x300mm is to carry a (8) UDL on the
entire span. If the tensile stress is limited to 3MPa, what is the maximum UDL that can
be applied on the beam?

6 93) Derive the classic bending equation. (9) b) A simply supported rectangular wooden beam of
span 2.5m has cross section (6) 150mmx250mm and carries a central point load of 10014. Find
the shear stressat 50mm below the top edge of the middle cross section.

PARTC
Answer any two full questions, each carries 20 marks.

7 93) Draw Mohr’s circlefor the two-dimensional state of stress shown in Fig. 2. Find (14) the

principal stresses and their planes.

ജ്‌ N/mm

60 Nom

120 N/mm. _ 120 Nut

60 Nom
80 N/mm Fig. 2

b) A solid circular shaft is to transmit 75 kW power at 200 rpm. If the shear stress (6) is
not to exceed 50 MPa, find the diameter of shaft. G = 100 GPa.

8 a) A 2m long thin cylindrical shell (both ends closed), internal diameter 90cm and (10)
thickness 12mm, is subjected to internal pressure 2N/mm?. Find 1) hoop and longitudinal
stresses, 2) changes in diameter and length shell. Take E = 2x10° N/mm? and Poisson’s ratio =
0.3.

b) Derive an expression for Euler’s buckling load for a column fixed at both ends.
(10)

9 a) Using moment-area method, find the deflection and slope at the free end of a (10) cantilever
applied with a couple at the free end.

b) Find the buckling load given by Rankine’s formula for a tubular strut hinged at
(10)

both ends, 6 m long having outer diameter 15 cm and thickness 2 cm. Given, E =
2x 10°N/mm?, ടേ 5671/1022 and Rankine’s constant, a= 1/1600. For what length

of the column does the Euler’s formula cease to apply? ****

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