Strength of Material

June-2006
SOM

Q.1 (a) Draw the engineering curve for mild steel on stress Vs strain graph and answer
the following: 4
(1) Ultimate stress is higher than breaking stress on the curve. 3
(2) Elastic limit is higher than proportional limit. 3

(b) A vertical bar of uniform section fixed at both its ends is axially loaded at
intermediate sections by 5000N and 3000N as shown in fig. Find the reactions at
both ends. 10

Q.2 Draw shear force and bending moment diagrams for simply supported beam at
ends shown in fig. 2. 20

Q.3 (a) Write assumptions made in the theory of pure bending. 8

(b) Three beams have the same length, same allowable bending stress and are
Subjected to same maximum bending moment. The cross-sections of the beams
are a circle , a square and a rectangle with depth twice the width . Find the ratio of
the circular and rectangular beams with respect to the square beam. 12

Q.4 (a) A cantilever of length 6 meters carries a point load of 100 N at the free end.
Determine the slope and deflection at the free end.
(Take 1xx =8.4x107mm4 and E = 200kN/mm2) 14

(b) What do you understand by roller, hinged & fixed end supports. 6

Q.5 (a) Differentiates between buckling load and crushing load. 6

(b)A hollow alloy tube of 4 meters long with external and internal diameter equal to
40 mm and 25 mm respectively was found to extend by 5mm under a tensile load
of 50 kN. Find the buckling load for the tube, when used as a column with both
ends pinned. Also find the safe compressive load for the tube, with factor of safety
of 2. 14

Q.6 (a) Explain torsional rigidity of shaft. 5

(b) A shaft has to transmit 120 KW at 160 rpm. If the shear stress is not to exceed 70 N/mm2 and twist in a length of 3.5 m must not exceed 1°, find a suitable diameter. Take C= 8x104 N/mm2. 15

Q.7 (a) Define spring constant for open helical spring. 5
(b) Find the expression for the stiffness of spring (open helical spring). 15

Q.8 Write short notes on any four of the following: (5x4)
(a) The values of poison’s ratio.
(b) Bulk modulus
(c) Circumferential stresses in seamless thin walled cylinder
(d) Long column
(e) Eccentric loading on vertical column.

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