Dr.A.P.J.Abdul Kalam University BE - ME III SEM Strength of Materials [ME-221] Dec - 2020 Question Paper

Dr.A.P.J.Abdul Kalam University

Bachelor of Engineering

Third Semester Main Examination, Dec-2020

Strength of Materials [ME-221]

Branch-ME

Time: 3:00 Hrs Max Marks 70

Note : Attempt any five questions.

All question carry equal marks.

Q.1 (a) Explain the terms strain, Shear strain, young’s modulusand modulus of rigidity.

(b) A tension bar taper from (d+a) diameter to (d-a) diameter Prove that the error

involved in using the mean diameter to calculate the young modulus is (10a/d)^2 percent.

Q.2 (a) A closed coiled helical spring has its free length as 120mmit absorbs 40 N-m of energy when fully

compressed and the coil are in contact. The mean coil diameter is 80mm. Determine the diameter of

steel wire required and number

of coil, if maximum shear stress is to be 120MPa, G=80GPa.

(b) A 280mm*120mm*10mm I beam in to be used as a cantilever of 3.6 m length. Find the uniformly

distributed load which can be carried safety if the permissible stress is 125 MPa.

Q.3 (a) What is the assumption made in the theory of torsion?

(b) Develop an expression for strain energy in a shaft subjected to torsion.

Q.4 (a) What do you mean by Theories of failure? What is their importance

(b) What is meant by equivalent length of columns? What are its values for different end conditions of

column?

Q.5 (a) Derive the equation for principal stress from a given two dimensional stress element

(b) Derive the relation.

Q.6 (a) Deduce an expression for allowable tungsten moment of a thin walled tube. Also find an

approximate Expression

for strength weight ratio of such tube.

(b) Derive the expression of stress and deflection of helical spring of circular wire.

Q.7 (a) Derive Euler’s formula for column with pinned ends.

(b) Briefly explain true stress and true strain.

Q.8 (a) Briefly describe the construction of leaf spring with neat sketch

(b) A shaft transmits 280 KW of power at 160 rpm. Determine The diameter of solid shaft to transmit

the power.

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