MU Civil Engineering (Semester 3)
Strength of Materials
December 2016
Total marks: --
Total time: --
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

1(A) A new fiber-optic cable was laid under the Pacific ocean from Califormia to Japan, a distance of 13,300 km. The cable was unreeled (unwound) from shipboard at a mean tempreature of 22°C & dropped in to the ocean. Ocean had a mean tempreature of 5°C. The coefficient of linear expansion of the cable is 75×10-6C. Determine the length of the cable that must be carried on the ship to span the 13,300 km.
4 M
1(B) A Tensile Test on a Mild Steel specimen 44 mm in diameter & 200 mm long was conducted & it was observed that: Elongation with 55 kN load (within imit of proportionalty) was 0.04 mm; Yield load= 180 k.N, Calcuate Young's Modulus & Yield Point Stress.
4 M
1(C) Choose & write the correct option.
i) When both the ends of a column are fixed, the Eluer's crippling load is F. If one end of the column is made free, then the value of crippling load will change to:
a) F/4
b) F/2
c) F/6
d) 4F
ii) Two people, each weighing (W), are sitting on a plank of length (L) flaoting on water, at (L/4) from other end. The water exerts an upward UDL of (2W/L) on the plank. Neglecting the self weight of the plank, the bending moment at the centre of the plank is:
a) WL/8
b) WL/16
c) WL/32
d) Zero
iii) The ratio of final length of initial length of a member is called:
a) Linear strain
b) Stress
c) Young's modulus
d) None of these
iv) A soild circular shaft is to transmit a power (P) kW, at (N) revolutions per minute. For a given maximum shear stress, the shaft diameter will be proportional to:
a) (P/N)fraction1and3
b) P/N
c) (P/N) fraction2and3
d) (P/N) 3
4 M
1(D) Calculate & locate the Core or Kernel of a T-Section of flange dimensions (20mm×100mm) & web dimensions(120mm×25mm).
4 M
1(F) State the assumptions of Pure Bending Theory.
4 M

2(A) A hollow shaft of diameter ratio(3/8) is required to transmit 635 kW at 120 RPM, the maximum torque being 21% greater than the mean. The shear stress is not to exceed 66 MN/m2 & the twist in a length of 3 m not to exceed 1.5 degrees. Calculate the maximum external diameter which would satisfy both the conditions. Take modulus of rigidity=87GN/m2.
8 M
2(B) The principal stresses at a point across two prependicular planes are shown in fig.1. Find the normal stress, tangential stress & the resultant stress & its obliquity on a plane at 23° with major pricncipal plane. Use analytical as well as graphical method.
8 M
2(C) An object of 140 N weight falls by gravity, a vertical distance of 5m,when it is suddenly stopped by a collar at the end of a vertical road of length 10 m & diameter 20 mm. The bar top rigidly fixed. Calculate the maximum stress & strain induced in the bar due to impact. Take E = 200 GN/m2 for the rod material.
4 M

3(A) A load of 120kN is carried by a hollow column made of cast-iron. The external diameter is 240 mm & the internal diameter is 200 mm. If the eccentricity of the load is 45mm, find:
i) The maximum & minimum stress intensities.
ii) Up to what eccentricity, there is no tensile stress in the column?
8 M
3(B) When is the shell called as thin shell? A cylindrical shell 1 m long & 225 mm internal diameter having 8 mm metal thickness is filled with fluid at atmospheric pressure. If an additional 24 cm3 of fluid is pumped in to the cylinder find the pressure exerted by the fluid on the cylinder & the hoop stress induced.
8 M
3(C) The chair is supported by an arm that is hinged so that it rotates about the vertical axis at A. If the load on the chair is 800 N & the arm is the hollow tube section having the dimensions shown in fig.2, determine the maximum bending stress at section a-a.
4 M

4(A) The Beam (fig.3) is subjected to the loading shown. Draw the Shear Force & Bending Moment Diagrams for the beam.
8 M
4(B) A hollow cast iron column has both the ends fixed . Column length is 6 m, external diameter is 200 mm. It carries a safe axial load of 510kN. The factor of safety is 6. Take ultimate compressive stress as 575 MN/m2 & Rankine's constant as (1/1600). Determine the thickness of the column.
8 M
4(C) For a given material, Young's modulus is 138 GN/m2 & shear modulus is 46 GN/m2. Find the bulk modulus.
4 M

5(A) A simply supported beam carries a UDL of 6 kN/m over the entire span of 6m. The cross-section of the beam is a T-section having a flange of (150mm×20mm) & a web of (30mm×180mm). The overall depth is 200 mm. Calculate the maximum shear stress & draw the Shear Stress Distribution Diagram.
8 M
5(B) A simply supported I-section steel beam (Fig.4) has cross-sectional area shown. If w = 9kN/m, determine the absolute maximum bending stress in the beam.
8 M

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