No.

No. of Questions : 091

e : 03 Hours

B.Tech. (Sem. - 3'd)

STRENGTH OF MATERIALS - ISUBJECTCODE: ME-201

PaoerID: [A080llINote : Please fill subject code and paper tD on OMRI

[Total No. of Pages : 03

Maximum Marks : 60

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3)

to Candidates:

Section - A is Compulsory.Attempt any Four questions flrom Section - B.

Attempt any Two questions from Section - C.

Section - A

(t0x2=20)a) What shall be the longitudinal strain of a cylindrical vessel of diameter

'50mm' and thickness '5mm' if it is subjected to an intemal pressure

'p'? The Young's modulus of elasticity of the material is 200GPa andmodulus of rigidity is 80GPa.

b) A bar 40mm in diameter is subjected to an axial load of 40kN. Theextension of the bar over a gauge length of 200mm is 0.3mm. Find theYoung's modulus of elasticity of the material?

c) Write down the expressions relating the shear force, bending momentand unifonnly distributed loading on a beam.

What will happen to the deflection of a cantilever beam ifthe modulus ofelasticity the beam is doubled and the second moment of area is halved?

Briefly explain the theories of failure applicable to ductile materials.

A steel bar of2m length is fixed at both ends atl\oC.lfthe coefficientof thermal expansion is 1l x l0{/"C and the modulus of elasticity is

200GPa, find the stress experienced by the bar if the temperature isreduced to 18"C.

-q) Briefly explain the diff'erence betlveerl 'section modulus' and 'second

nlonlcnt of arel' of a section.

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A simply supported beam of span I carries a 'udl' of intensity 'w'throughout its span. Ifthe width 'b' ofthe beam is constant throughoutthe span, what will be the beam's depth at the mid-span if the perrnissiblebending stress is '/'?Plot the shear stress vs shear strain curves for brittle and ductile rnaterialssubjected to torsion?

Briefly explain the concept of the point of contra-flexure.

Section-B Gxs=20)

Q2) A cylinder is attached to a wall at point A by a fixed support as shown in the

diagram belou'. The half of the cylinder from point A to point B is made ofsteel (E : 200 GPa) and has a length of I m and a diameter of I cq the halfofthe cylinder from point B to point C is rnade of aluminum (E=70 GPa) and

has a length of I m and a diameter of 1cm. Before the cylinder is loaded, the

free end (point C) is separated frorn a second wall by a distance of 0.5rnm.

At what value of the load P does the cylinder first touch the second wall?

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Determine the prop-er diarneter D for a hollorv steel shatt (inner diarneter: 0.45 times the outer diameter) to transmit 200 HP at 3600 rpnr, if the

working stress in shear in the bar is 42lvlPa. Also find the angle of twist per

unit length of the slraft. Given that G : l0iMPa for the rnaterial of the shaft.

A compression meurber of 500 r.nrn etfective length consists of a solid2,1 mm diarneter aluminiuu.r rod. ln older to reduce the weight of tlle metnber

b1' ?5%. then solid rod is replaced by' a lrollow rod with D. = 24mm and

D,: ll rrrr.r.r. Detennine the per cent reduction in the critical load.

A timber heam 100 rtrrn u ide arrd I 50 rnnr tlecp carries a unilbrrull distribtrted

load or er a span oi2rn. I lthc perrtrissitrte stresses are 28MPa in bending ar-rd

l\lPu in shear. calculate thc maxirnrtrn t-JDl- rvhich can lrc carried [r)'thu'

bc:irr.

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