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(O

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2A balance rnaas of value - III is placed3diametrically opposite to the crank at crankradius r. What IS the expression for theunbalanced for-ce along the line of stroke of areciprocating engine for angular position e of'thecrank with respect to the line of stroke ?

(ii) State the phenomenon of hunting In aspring controlled governor.Explain briefly vibration isolation andtra rrarn is sibility.The natural frequency of a system. put on 'afoundation is wn. The operating frequencyis 00. What is the ~.ini=u:m value of (: n Jbeyond which the vibration isolation ISpossible or .meaningful?

(d, The Mohr's circle for a p1ane stress IS a circle ofradrua R with its origin at +2R on o axis. Sk~tchthe Mohr~s circle and determine O"lTIax' O"min' (jav'(Txy)max for this situation.

(e) Briefly explain the role of idle gears in a aimplcgear train, with the }:lelpof neat sketches.

(D List two tem.porary fasteners and explairi theworking of one of these.

-1. (a)

(b) (i)

(c) (i)

(ii)

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. I .. . . . ,

SECTION A

What is an isochronous governor ?

2 (Contd.J

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(g) The state of stress at a point in a loaded tnachinerriornber is given by theprincipal stresses. -rr1= 600 MPa, 0'2 = 0 and 0'3= - 600 MPa.(i) What is the magnitude of the rnaxjrrnarnshear stress?

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(ii) What is the inclination of the plane onwhich the rnaxirrrurn shear stress acts withrespect to the plane -on which therrrax'imurn 'principa~ stress 0'1 acts?

(h) Two long columns are made .of identical lengths 'l'and flexural rigidities 'EI'. Column 1 is hinged atboth ends whereas for colu:mn 2 one end is fixedand the other end is free.(i) Write the expression for Euler's buckling

load for cnlurrrri 1.(ii) What is the ratio of Euler's buckling load of

colrrrnrr 1 to that of colurnn 2 ?(i) A close coiled helical spring rrtade of wrr-e

djarneter d has mean coil radius R, rrurrrber ofturns nand rnodulua of rigidity G. The spring issubjected to an axial compression W.(1) Write the expression for the stiffness of the

sp.rrrrg;(2) What is the magnitude of the rrra.xrrrrurn

shear stress induced in the spring WIreneglecting the curvature effect?

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55- C - 36 - D - 9 - S - 28

(j) List the conditions under which a rope drive ISpreferred to a belt drive.

(k) What is achieved by using a metallic singlecrystal casting? Give one application of a s'irig'lecrystal casting :made of wasp alloy.

(1) In investment casting process two types ofceramic slurries are used. Why do we use themand in what sequence are they applied?

(rn) What is the shape of a runner for making asand mould ? On what considerations is thisshape selected?

(ri) What does the following marking on a grindingwheel denote ?

(p) COITIpare the drilling and boring oper-e.t.ion.s inrelation to cutting actrion, accuracy andapplications .

(0) Show crater wear arrd flank wear on a singlepoint cutting tool. State the factors responsiblefor wear on a turning tool.

. (q) What is the effect on order quantity when thedornarrd increases by four-fold in basic orderpoint inventory system and other fact.or-sremainunchanged ? Explain.

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A-FTF-J-NFB 5 [Contd.]

,

(r-) A cornpa.ny 1S faced with a situation where itcan either produce aorrre It.ern by adding.additional infrastructure which will cost t.bernRs. 15,007000/- but unit cost of production will beRs. 5/- each. Alternatively itcan buy the sameiteIll from a vendor at a rate of Rs. 20/- each.When should the company add to its capacity interms of demand of items per arrrrurn? Draw thediagralTI to show the BEP.

(s) Define the term. ~standard Lirne"and list the_common allowances given in work standard.

(t) Pointers are commonly used in 'C' for creatinglinked lists. Write a FORTRAN code toirnplement pointers, that is, to traverse thelinked list. 2x20=40

. .

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OJ) Poi ssori's ratio. 10

SECTION B2. (a) A cantilever of circular solid cross-section .is

fixed at one end and carries a concentrated loadPat the free end. The djarnet.er-at the free end is200 lllm and increases uniformly to 400 nun atthe fixed end over a length of 2 m. At whatdistance from. the free end will the bendingstresses in the cantilever be maximum. ? Alsocalculate the value of the maximum bendingstress if the concentrated load P=30 kN. 15

(b) In a torsion test, the apecimeri is a hollow shaftwith 50 mrn external and 30 rnrn internald'iarrret.er. An applied torque of 16 kN-rn is foundto produce an angular twist ofO4 measured ona length of 02 rn of the shaft. The Young'smodulus of elasticity obtained from a tensile testhas been found to be 200 GPa. Find the values of(i) Modulus of rigidity,

(c) A cylindrical shell has the following dirn.eras'iorrsLength = 3 rnInside diameter = 1mThickness of metal = 10 'rrrrnInternal. pressure = 15MPa

Calculate the change in diInensions of the shelland the Illaxirnum intensity of shear stress

- induced. Take E = 200 GPa and Poisacrr's ratio ;;::v = 03. 15

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(a) (i) Explain the term

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Find the stroke of the upper piston when theprilnary force is balanced.

(a) The screw of a car lift has 150 rrrrn dia. withsquare threads of 50 TIlIn pitch and lead of100 rnm,Assume 1000 Nis required for lifting ofthe car and thread friction coefficient is 020.(i) Cornput.ethe torques required to rotate the

screw to raise the car and lower the car.Also COITlpute the overall efficiency of thescrew.

4..

(ii)

-Figure 3(b)

What is the flaw in the above design ?(b) A simple gear train consists of three gears with

18, 16 and 72 teeth. The 18 teeth pinion isconnected to a 4 kW electric rnotor running at2400 r'prn, Design the shaft for 72 teeth gear ifthe shearing stress is not to exceed 60 MPa intheshaft.

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(c) Find the equivalent spring constant if the belowshown spring systems are replaced by a singlespring. 5

(d) ~Mostof the times the rotating disc-shafts havekeys; under such conditions it cannot be aas'urnodthat the shaft has a uniforTIl. cross-section. Forsuch a disc-shaft syat.ern how will you detenninethe limits of speed for instability? 5

K

(i) (ii)

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K

(iii)

[Contd.]

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of these processes:(i) Direct Extrusion.(ii) Indirect Extrusion(iii) Hydrostatic Extrusion(iv) Itnpact Extrusion

20

SECTION C5. (a) Explain the three types of oxy-acetylene flames.

Indicate with the help of sketches the variouszones, respective. temperature ranges andapplications of each type of flame. 20

(b) Explain the processes of extrusion given below.Indicate one typical product filade through each

6. (a) Determine the opt.irrrurn cutting speed for anoperation on a lathe machine using the followingi.nfor-mat.iori :

Tool change timeTool regrind t.irrreMachine running costDepreciation of toolregrind

3 min3 rninRe. 050 per min :

Rs.50The constants in the tool life equation are 60 and02. 10

(b) (i) Why are the alignm.ent tests done onmachine tools?Give the list of C01l1.1TIOn testing equiprrtentneeded for aligrrmemt tests on a generalpurpose lathe.

(iii) Write steps to check straightness ofcarriage in a horizontal plane with the helpof sketches. 15

(ii)

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Calculate Tracking Signal for each rnorrt.h.Cornrnerrt on the forecast model. 10

(c) (i) What IS t.he principle of metal r-ernoval InEDM process ?

(ii) Describe the proceas with the help ofsketch.

(iii) List advantages - and. limitations of theayatorn. 15

. (a) (i) List cornrnon time-series forecastingmodels. Exp'la in airnp le exponentialsmoothing rnet.hod of forecasting demand.What are its limitations?

(ji) The rnontb ly forecast and demand values ofa firm are given below:Month Forecast units Demand units

Jan 100 97Feb 100 . 93Mar 100 110Apr 100 98May 102 130Jun 104 133Jul 106 129

-Aug 108 138Sep 110 136Oct 112 124Nov 114 139Dec 116 125

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Technician Hours to Complete JobJob 1 Job 2 Job3 Job 4.

A 20 36 31 27-B 24 34 45 22C 22 . . 45 38 18D 37 40 35 28- ,

(b) Four technicians ,are required to do four differentjobs. Estimates of time to complete every job asprovided by the technicians are as below:

Assign the jobs to technicians to rrrirrirniz.e thetotal work-time. State the steps taken Inthealgorithm used.

(c) Prepare a flow chart and write a progralll 1TIFORTRAN for the follo"\.vingproblemThe cutting tool life (T) for Illachining operationis given by Taylor's equation vTn = C where v isthe cutting speed and C, n are constants. An MSworkpiece of 50 rr1111 dia. is turned With a carbidetool with n = 010 and C = 150. It is proposed tostudy the variation of tool life with the rpm of theworkpiece at which turning is perforrn_ed. AssuTIlethat the speed of spindle of lathe can bevaried fr-orn100 r-prnto 2000 r'prn in the steps of100 rprrr.

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