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0000020201121902
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY

Third Semester B.Tech Degree (S,FE) Examination December 2020

Course Code: CE201
Course Name: MECHANICS OF SOLIDS

PART A
Answer any two full questions, each carries 15 marks

Define Poisson's ratio and prove that the limiting value of Poisson's ratio is 0.5
A circular rod of 100 mm diameter and 500 mm long is subjected to a tensile
force of 900 kN. Determine the change in volume if Poisson's ratio is 0.3 and
Young's modulus is 2x10° N/mm.

A compound steel tube consists of a steel tube of 120 mm internal diameter and
140 mm external diameter and an outer brass tube whose external diameter is
160 mm and internal diameter is 140 mm. The composite bar is then subjected
to an axial compression of 500 KN. If 'E' for steel is 200 kN/mm? and for brass
100 kN/mm?. Find the stresses in and the amount of deformation. Both the tubes
are of length 180 mm.

Draw the stress-strain diagram for mild steel and explain all salient points.

A bar of cross section 30 x 30 mm and 250 mm long is subjected to a pull of
100 KN in the direction of its length. The extension of the bar was found to be
0.125 mm, while the decrease in each lateral dimension was found to be 0.0038
mm. Find (i) Poisson's ratio, (ii) Young's modulus of elasticity, (iii) Modulus of
rigidity and (iv) Bulk modulus.

Derive an expression to find strain energy due to axial load.

A steel rail is 13 m long and is laid at a temperature of 25°C. The maximum
temperature expected is 45°C. Take E=2 x10° MN/m? and « = 12:10 /°C

(i) Estimate the minimum gap to be left between the two rails so that the
temperature stresses do not develop in the rail.

(ii) Calculate the thermal stresses developed in the rails if a 2 mm gap is
provided for expansion.

(iii) If the stress developed is 20 MN/m/?, what is the gap between the rails?

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Duration: 3 Hours

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