6 MACHINE DESIGN-I - Gate · PDF file6 MACHINE DESIGN-I SUBJECT CODE : 337551 ... Q.3 Design a cotter joint to carry a maximum load of ... The bolt is made of plain carbon steel 30C8

6MACHINE DESIGN-I

SUBJECT CODE : 337551 (37)

CSVTU PREVIOUS YEARS’ QUESTION PAPERS

Nov-Dec 2007 6-1

Apr-May 2008 6-3

Nov-Dec 2008 6-5

Apr-May 2009 6-7

Nov-Dec 2009 6-9

Apr-May 2010 6-12

Nov-Dec 2010 6-14

Apr-May 2011 6-17

Nov-Dec 2011 6-19

Apr-May 2012 6-21

Nov-Dec 2012 6-23

Apr-May 2013 6-25

Nov-Dec 2013 6-27

Apr-May 2014 6-30

Nov-Dec 2014 6-32

Apr-May 2015 6-33

Nov-Dec 2015 6-37

: SARASWATI SHIKSHA MANDIR, NEAR TIKARAPARA POLICE STATION, SANTOSHI NAGAR, RAIPURRAIPUR

SCHOLARSHIP TESTFOR GATE 2018 ASPIRANTS

Test PatternTest Date

th18 Sep. 201630 Questions 50 Marks 90 Minutes

9630520016RAIPUR

BHILAI : PLOT NO. A-213, STREET NO.-27,NEAR CANARA BANK, SMRITI NAGAR, BHILAI

MECHANICAL CIVILNEW BATCHES FOR

GATE 2018

0788-6499334BHILAI

9630520016RAIPUR

BHILAI

: SARASWATI SHIKSHA MANDIR, NEAR TIKARAPARA POLICE STATION, SANTOSHI NAGAR, RAIPURRAIPUR

: PLOT NO. A-213, STREET NO.-27,NEAR CANARA BANK, SMRITI NAGAR, BHILAI

STARTING ON

MECHANICAL ENGINEERING

TH29 AUG. 2016 - BHILAI TH15 SEP. 2016 - RAIPUR

CSVTU PREVIOUS YEARS’ QUESTIONPAPERS|6-1

FOR DESCRIPTIVE SOLUTION REFER GATEMENTOR PUBLICATION (MACHINE DESIGN - I) BOOK FOR CSVTU

Nov-Dec 2007

UNIT-1

Q.1 Explain the following terms:(i) Design stress (ii) Factor of safetyAns. Refer Q. No.1.3 in Unit 1.Q.2 (i) A steel shaft is subjected to a constantbending moment of 10 kN-m and a constanttorque of 35 kN-m. Using a factor of safetyequal to 2.0 determine the diameter of shaftapplying Distortion energy theory of failureand a maximum shear stress theory of failure.Yield point stress = 700 MN/m2.(ii) What steady load P can be applied on acylindrical bar shown in below figure withoutexceeding yields strength of material at notchroot. The value of ultimate stress=600N/mm2.Taking notch sensitivity into action, find the value ofP which can be applie without exceeding endurancelimit of material. Steel-annealed & normalized.

65

If the value of in fluctuates between 2 F and 4 F, findthe value of F. Apply soderberg equation with factorof safety = 2.0 surface of bar is matchedAns. Refer Q. No.1.30 in Unit 1.Q.3 Design a roller chain drive to connect a 15 kW 1500rpm electric motor to a centrifugal pump running at750 rpm. The service conditions involve moderateshocks.(i) Select a proper roller chain and give a list ofits dimensions.(ii) Determine the pitch circle diameters ofdriving and driven sprockets(iii) Determine the number of chain links(iv) Recommend the correct centre distancebetween the axes of sprockets.The conditions of operations are: Constant load,fixed centre distance, continuous lubricationcontinuous running.Ans. Not in Syllabus.

UNIT-2

Q.1 Prove that a square key is equally strong in shearand compression.Ans. Refer Q. No.2.19 in Unit 2.Q.2 Design a knuckle joint (with fork and eye) towithstand a load of 10000 N. The material used forall components have the following properties:Ultimate tensile strength = ultimate compressivestrength = 480 N/mm2; shear strength = 360N/mm2, FOS = 6.

Ans. Refer Q. No.2.18 in Unit 2.

Q.3 Design a cotter joint to carry a maximum load of50000 N. All the components are made of the samematerial having the following stress:Tensile stress = 20 MN/m2, Compressive stress = 50MN/m2Shear stress = 15 MN/m2.Ans. Refer Q. No. 2.12 in Unit 2..

.

6-2|MACHINE DESIGN- I

MECHANICALeryc GATEMENTOR

UNIT-3

Q.1 Differentiate between a bolt and tap bolt.Ans. A bolt is a threaded fastener mated with a nut. Oneend mates with a tapped component and the otherwith a standard nutA tap bolt is a bolt with a head on one end and athread on the other end, to be screwed into somefixed part, instead of passing through the part andreceiving a nut.Q.2 A screw jack is to lift a load of 80 KN through ahigher of 400 mm. The elastic strength of screwmaterial in tension and compression is 200 MPa andin shear 120 MPa. The material for the nut isphosphor-bronze for which the elastic limit may betaken as 100 MPa in tension, 90 MPa incompression and 80 MPa in shear. The bearingpressure between the nut and the screw is not toexceed 18 N/mm2. Design and draw the screw jack.The design should include the design of:(i) Screw (ii) Nut(iii) Handle and cup (iv) BodyAns. Refer Q. No. 4.45 in Unit 4.Q.3 The structural connection shown in figure issubjected to an eccentric force P of 10 kN with aneccentricity of 500 mm. The centre – distance

between bolts 1 and 2 is 200 mm, and the centre –distance between bolts 1 and 3 is 150 mm. All thebolts are identical. The bolts are made from plaincarbon steel 30C8 (Syt = 400 N/mm2) and factor ofsafety is 2.5. Determine the size of the bolts

Ans. Refer Q. No. 4.12 in Unit 4.Q.4 A bolted joint is used to connect two components.The combined stiffness of the two components istwice the stiffness of bolt. The initial tightening ofnut results in a pre-load of 5 kN in the bolt. Theexternal force of 10 kN creates further tension inbolt. The bolt is made of plain carbon steel 30C8with yield point stress in tension = 400 N/mm2 andfactor of safety is 3. There are coarse threads on thebolt. Determine the size of bolt.Ans. Refer Q. No. 4.17 in Unit 4

UNIT-4

Q.1 Define the efficiency of riveted joint.Ans. Refer Q. No. 5.4 in Unit 5.Q.2 A rectangular cross-section bar is welded to asupport by means of fillet weld as shown in figure.Determine the size of the welds if the permissibleshear stress in the weld is limited to 75 MPa.

Ans. Refer Q. No. 5.27 in Unit 5.Q.3 Design a double riveted butt joint with two coverplates for the longitudinal seam of a boiler shell 1.5m in diameter subjected to a steam pressure of 0.95N/mm2. Assume joint efficiency as 75%, allowabletensile stress in the plate 90 MPa, compressivestress 140 MPa and shear stress in the rivet 56 MPa.Ans. Refer Q. No. 5.14 in Unit 5.



UNIT-5

Q.1 Explain the difference between design of shaftbased on:Ans. Refer Q. No. 3.2 in Unit 3.Q.2 A machined surface shaft carries a completelyreversed bending moment of 3 kN-m and a torqueof 10.8 kN-m. The stress concentration factor forbending and torsion is 1.35. Take factor of safety =2.0. The ultimate strength of material

2825 /u N mm ; yield strength 2610 /yt N mm .Calculate the diameter of shaft based on maximumshear stress theory of failure. Neglect notchsensitivity.

Ans. Refer Q. No. 3.16 in Unit 3.Q.3 Design a clamp muff coupling to transmit 30 kW at100 rpm. The shaft and key are made of 40C8 steelhaving tensile yield strength = 320 N/mm2. Thereare six bolts connecting the two halves of thecoupling. The bolts are made of 45C8 steel havingtensile yield stress of 350 N/mm2. Take factor ofsafety = 4 and coefficient of friction between muffand surface = 0.3.

Ans. Refer Q. No. 2.29 in Unit 2.

Apr-May 2008

UNIT-1

Q.1 A plate made of steel 20 C8 2440 /ut N mm inhot-rolled and normalized condition is shown inbelow figure. It is subjected to a completelyreversed axial load of 30 kN. The notch sensitivityfactor q can be taken as 0.8 and the expectedreliability is 90% the factor of safety is 2. Determinethe plate thickness for infinite life.50

10

30kN 30kV

.Ans. Refer Q. No.1.31 in Unit 1.

Q.2 It is required to design a chain drive with a duplexchain to connect 15 kW, 1400 rpm electric motor toa transmission shaft running at 350 rpm. THeoperation involves moderate shocks.(i) Specify the number of teeth on the driving anddriven sprockets.(ii) Select a proper roller chain(iii) Calculate the pitch circle diameters of drivingand driven sprockets(iv) Determine the number of chain links(v) Specify the correct centre distance.Ans. Not in syllabus.

UNIT-2

Q.1 Design a knuckle joint for a tie rod of a circularsection to sustain a maximum pull of 70 kN. Theultimate strength of the material of the rod againsttearing is 420 MPa. The ultimate tensile andshearing strength of the pin material are 510 MPaan 396 MPa respectively. Determine the tie rodsection and pin section. The factor of safety = 6??Ans. Refer Q. No.2.16 in Unit 2.

Q.2 Design an draw (sketch) a cotter joint to support aload varying from 30 kN in compression to 30 kN intension. The material used is carbon steel for whichthe following allowable stresses may be used. Theload is applied statically.Tensile stress = Compressive stresses = 50 MPa;Shear stress = 35 MPa and Crushing stress = 90MPa.Ans. Refer Q. No. 2.8 in Unit 2.



UNIT-3

Q.1 A steel plate subjected to a force of 3 KN and fixedto a vertical channel by means of four identical boltsas shown. The bolts are made of plain carbon steel45C8 with 2380 /yt N mm If FOS = 2. Determinethe diameter of bolts.

Ans. Refer question 4.13 in unit 4Q.2 A steel plate subjected to a force of 8 kN is fixed to achannel by means of these identical bolts as shown.The bolts are made of 45C8 (Syt = 380 N/mm2). IFthe required FOS=2.5 Determine the size of the bots.

Ans. Refer question 4.11 in unit 4Q.3 A sluice valve used in water-pipelines, consist of agate raised by the spindle, which is rotated by thehand wheel. The spindle has single-start squarethreads. The nominal diameter is 36 mm, and thepitch is 6 mm. The inner and outer diameters of thefriction collar are 30 mm and 50 mm respectively.The coefficients of friction at the threads and thecollar are CI. 15 and 0.20 respectively. The weight ofthe gate is 7.5 kN, and the frictional resistance toopen the valve due to water pressure is 2.5 kN.Using the uniform wear theory for collar friction,calculate:(i) The torque required to raise the gate and(ii) The overall efficiency of the mechanismAns. Refer question 4.42 in unit 4

UNIT-4

Q.1 A steam boiler is to be designed for a workingpressure of 2.5 N/mm2 with its inside diameter 1.6m. Give the design calculations for the longitudinaland circumferential joints for the following workingstresses for steel plates and rivets:In tension = 75 MPa, In shear = 60 MPa, In crushing= 125 MPa.Ans. Refer Q. No.5.15 in Unit 5.Q.2 A welded connection of steel plates, as shown infigure… is subjected to an eccentric force of 10 kN.Determine the throat dimension of the weld if thepermissible shear stress is limited to 95 N/mm2.Assume static condition.

Ans. Refer Q. No.5.30 in Unit 5.



UNIT-5

Q.1 An intermediate shaft of a gear box, supporting twospur gears A and B and mounted between twobearings C1 and C2 shown in below figure. The pitchcircle diameters of gears A and B are 500 and 250mm respectively. The shaft is made of alloy steel 20MnCr5 2 2620 / / andut ytN mm N mm . Thefactors Kb and Kt of the ASME code are 2 and 1.5respectively. The gears keyed to the shaft.Determine the shaft diameter.Ans. Refer Q. No.3.14 in Unit 3.Q.2 Design a protective type of cast iron flange couplingfor steel shaft transmitting 15 kW at 200 rpm andhaving an allowable shear stress of 40 MPa. Theworking stress in the bolt should not exceed 30MPa. Assume that the crushing stress is twice thevalue of its shear stress. The maximum torque is25% greater than the full load torque. The shearstress for cast iron is 14 MPa. Same material is usedfor shaft and key


Nov-Dec 2008

UNIT-1

Q.1 Define stress concentration factor.Ans. Refer question 1.17 in Unit 1.Q.2 A cantilever beam made of cold drawn steel

2 240 8 600 / 380 /andut ytC S N mm S N mm as

shown below. the force P acting at the free endvaries from 50 150 .N to N The expected

reliability is 90% and the FOS = 2. The notchsensitivity factor at the fillet is 0.9. Determine thediameter "d" of the beam at the fillet cross-section.

50 150P N N

.

Ans. Refer question 1.44 in Unit 1.

Q.3 It is required to design a chain drive connect a 5 kW,100 rpm electric motor to drilling machine. THespeed reduction is 3:1. The centre distance shouldbe approximately 500 mm.(i) Select a proper roller chain for the drive(ii) Determine the number of chain links(iii) Specify the correct centre distance between theaxes of sprockets.Ans. Not in syllabus

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UNIT-2

Q.1 What are the functions of key?Ans. Refer Q. No.2.19 in Unit 2.Q.2 It is required to design a knuckle joint to connecttwo circular rods subjected to an axial tensile forceof 50 KN. The rods are co-axial and a small amountof angular movement between their axes ispermissible. Design the joint and specify thedimensions of its components. Select a suitablematerial for the parts.

Ans. Refer Q. No.2.17 in Unit 2.Q.3 It is required to design a cotter joint to connect twosteel rods of equal diameter. Each rod is subjectedto an axial tensile force of 50 KN. Design the jointand specify its main dimensionsAns. Refer Q. No.2.10 in Unit 2.

UNIT-3

Q.1 What are the types of threads for power screws?.Ans. Refer Q. No. 4.22 in Unit 4.Q.2 Design a screw jack to lift a load of 100 kN through aheight of 300 mm. Assume

400 , 200 , 300 ,u u yMPa MPa MPa

10b MPa The outer diameter of the bearingsurface is 1.6 d1 and inner diameter of bearingsurface is 0.8 d1, coefficient of friction between thecollar on screw and C.I. cup is 0.2. The co-efficient offriction between the steel screw and bronze nut is0.15. Take factor of safety of 5 of screw and nut buta factor of safety for the operating lever as 2.5.Ans. Refer Q. No. 4.45 in Unit 4.Q.3 A wall bracket is attached to a wall by means of fouridentical bolts, two at A and two at B as shown infigure. Assuming that the bracket is held against thewall and prevented from tipping about point C by allfour bolts and using an allowable tensile stress inthe bolts as 35 N/mm2, determine the size of thebolts on the basis of maximum principal stresstheory.

Ans. Refer Q. No. 4.8 in Unit 4..

UNIT-4

Q.1 What are the different types of welding methodsused in fabrication work?Ans. Refer Q. No.5.21 in Unit 5.Q.2 A rectangular cross-section bar is welded to asupport by means of fillet weld as shown in figure.Determine the size of the welds if the permissibleshear stress in the weld is limited to 75 MPa.



Ans. Refer Q. No. 5.27 in Unit 5.Q.3 Design a double riveted butt joint with two coverplates for a longitudinal seam of a boiler shellhaving 0.75 m internal diameter the maximumsteam pressure inside the boiler is 1.55 N/mm2.

Use the following dataPermissible tensile stress for the boiler shell = 90N/mm2Permissible shear stress for rivet / shell = 56N/mm2Permissible compressive stress for the rivets /holes = 140 N/mm2Efficiency of double riveted longitudinal butt joint =75%Ans. Refer Q. No. 5.14 in Unit 5.

UNIT-5

Q.1 What is the function of transmission shaft?Ans. Refer Q. No.3.1 in Unit 3.Q.2 A transmission shaft with a uniformly distributedload of 10 N/mm is shown in figure (a). Themaximum permissible deflection of the shaft is(0.003L), where L is the span length. The modulusof elasticity of the shaft material is 207000 N/mm2.Determine the shaft diameter by Castigliano’stheorem.

.

Ans. Refer Q. No.3.13 in Unit 3.Q.3 A rigid coupling is used to transmit 50 KW power at300 rpm. There are 6 bolts. The outer diameter ofthe flange is 200 mm. The coefficient of frictionbetween the flanges is 0.15. The bolts are made ofsteel 45 C8(Syt=380 N/mm2) & FOS = 3. Determinethe diameter of the bolts. Assume that the bolts areset in large clearance holes. The recess diameter is150 mm..Ans. Refer Q. No. 2.36 in Unit 2.

Apr-May 2009

UNIT-1

Q1. What are the advantages and disadvantages of chaindrive?.Ans. Not in Syllabus.

Q.2 A 12 KW electric motor running at 1200 rpm. Thecompressor speed is around 350 rpm. The centredistance is around 450 mm. The compressoroperates for 16 hours per day.

Ans. Not in Syllabus.

Q.3 What are the steps to be followed while designing achain drive?Ans. Not in Syllabus.



Q.4 A chain drive has some features of belt drive andsome of the gear drive. Explain Ans. Not in Syllabus.

UNIT-2

Q1. What is the purpose of using a gib along with acotter in a cotter joint?Ans. Refer Q. No. 2.2 in Unit 2.Q.2 Two steel rods are to be connected by means of asteel sleeve and two steel cotters. The rods aresubjected to a tensile load of 40 KN. Design the joint.The permissible stress in tension,

50 , 60 , 90t cMPa MPa MPa may beassumed.Ans. Refer question 2.14 in Unit 2..Q.3 Define critical resolved shear stress. How is itcalculated? Explain

Ans. Refer Q. No. 2.20 in Unit 2.Q.4 An automobile engine has a capacity of 250 N-m.The clutch is attached to its driven shaft by meansof six splines that is to slide when not under load.Determine the dimensions of the shaft and spline.The material of the shaft and splines is steel and theload is applied with a moderate shock. Themaximum pressure on the spline is 8.5 N/mm2.Assume length of the spline 1.5 times the shaftdiameterAns. Refer question 2.35 in Unit 2..

UNIT-3

Q.1 What is meant by screwed fastener and what arethe applications of screwed fasteners?.Ans. Refer Q. No. 4.1 in Unit 4.Q.2. A steam engine cylinder of 300 mm effectivediameter is subjected a steam pressure of 1.5N/mm2. The cylinder head is connected by means of8 bolts having yield strength of 320 MPa andendurance limit of 240 MPa. The bolts are tightenedwith an initial preload of 1.5 times that of steamload. A soft copper gasket is used to make the jointleak proof. Assuming a fatigue stress concentrationfactor of 1.4 and factor of safety of 2; determine thesize of the bolts required..Ans. Refer Q. No.4.18 in Unit 4.Q.3 Figure shows a screw clamp and nut, calculate : (a)The diameter of the screw, (b) The height of the nutand (c) The dimensions of the handle, for maximumclamping force 20cF KN force at the end of thelevel arm = 200 N=W, allowable compressive stressfor screw = 80 MPa c , Bearing pressure of screwand nut 20 ,bP MPa coefficient of friction betweenscrew and nut threads 0.15 Friction torque ofpad 2 40T N m , allowable bending stress forhandle 90b MPa .

dC




UNIT-4

Q.1 Which type of joint used for longitudinal joint of aboiler and why?Ans. Refer Q. No. 5.5 in Unit 5.Q.2 A boiler is made by welding the plateslongitudinally and circumferentially as shown infigure. The diameter of the boiler is 1m. Themaximum pressure is 1.5 N/mm2. Design both thejoints, using single-V butt weld for both the joints.The permissible tensile stress in the plate materialis 70 MPa. Also assume the strength of the plate andweld is the same.

1000

t


UNIT-5

Q.1 What are the purposes in machinery for whichcouplings are used?Ans. Refer Q. No.2.23 in Unit 2.Q.2 It is required to design a bushed pin type of flexiblecoupling for connecting the motor and centrifugalpump shaft. The details of the duty required fromthe pump are:Power to be transmitted = 18.5 kWSpeed of revolution/minute = 1000The diameter and pump shafts are 50 mm and 45mm respectively. Take the bearing pressure on therubber bush as 0.35 N/mm2 and the work shearingstress in the materials of the pins as 20 N/mm2.

Ans. Refer Q. No. 2.32 in Unit 2.Q.3 Enumerate the cases of shaft failure anddifferentiate between a shaft and an axle?A transmission shaft with keyways is subjected to amaximum torsional moment of 750 N-m, andmaximum bending moment of 1200 N-m. The leadsare suddenly applied, minor shocks areencountered and the allowable shear stress is 42MPa. Find the shaft diameterl.Ans. Refer Q. No. 3.1,3.3 & 3.15 in Unit 3.

Nov-Dec 2009

UNIT-1

Q.1 Explain factor of safety, notch sensitivity.Ans. Refer question 1.3 & 1.17 in Unit 1.Q.2 A flat plate subjected to a tensile force of 5 KN isshown. The plate material is grey cast iron 200FGand 2.5FOS . Determine the thickness of theplate. .

Ans. Refer question 1.35 in Unit 1.Q.3 A cantilever beam made of cold drawn steel

2 240 8 600 / 380 /andut ytC S N mm S N mm asshown below. the force P acting at the free end



varies from 50 150 .N to N The expectedreliability is 90% and the FOS = 2. The notchsensitivity factor at the fillet is 0.9. Determine thediameter "d" of the beam at the fillet cross-section.50 150P N N

Ans. Refer question 1.44 in Unit 1.Q.4 A compressor is to be actuated from a 10 KWelectric motor. The speed of the motor shaft is 1000rpm and the compressor speed being 350 rpm. Theminimum centre distance is 500 mm. The

compressor operates 16 hrs/day. Design a suitablechainAns. Not in syllabus.

Q.4 How do you accommodate the effect of keyway on ashaft?A standard spline connection 8 52 60 mm is usedfor the gear and the shaft assembly of a gear box in20 KW power at 300 rpm is transmitted by thesplines. The dimension of the splines are,60 ,D mm d 52mm and 2P 6.5 / ,b N mm0.06. Find:(i) The length of the hub of the gear(ii) The force required to shift the gear

Ans. Refer question 2.34 in Unit 2.UNIT-2

Q.1 Differentiate the temporary joint and permanentjoint give examples.Ans. Refer Q. No.2.1 in Unit 2.Q.2 Design a cotter joint to support a load of 80 KN intension. The material used is carbon steel for whichthe allowable stresses may be taken as

60 , 40 ,t MPa MPa 100c MPa respectively.Go for socket and spigot cotter joint.Ans. Refer Q. No.2.11 in Unit 2.Q.3 Design a knuckle joint to transmit 150 KN, thedesign stress may be taken as 75 MPa in tension, 60MPa in shear and 150 MPa in compression.Ans. Refer Q. No.2.15 in Unit 2.Q.4 How do you accommodate the effect of keyway on ashaft?

A standard spline connection 8 52 60 mm is usedfor the gear and the shaft assembly of a gear box in20 KW power at 300 rpm is transmitted by thesplines. The dimension of the splines are,60 ,D mm d 52mm and 2P 6.5 / ,b N mm

0.06. Find:(i) The length of the hub of the gear(ii) The force required to shift the gear.Ans. Refer question 2.34 in Unit 2 .

UNIT-3

Q.1 What are different types of stresses set up in boltsdue to initial tightening?Ans. Refer Q. No. 4.6 in Unit 4.Q.2 A steel bracket shown is secured to a wall by meansof four steel bolts. The load on the bracket is 15 KNwhich acts at a distance of 175 mm from the wall.Determine the size of the bolt.



Ans. Refer Q. No. 4.8 in Unit 4.Q.3 A screw jack is to lift a load of 80 KN through ahigher of 400 mm. The elastic strength of screwmaterial in tension and compression is 200 MPa andin shear 120 MPa. The material for the nut isphosphor-bronze for which the elastic limit may betaken as 100 MPa in tension, 90 MPa incompression and 80 MPa in shear. The bearingpressure between the nut and the screw is not toexceed 18 N/mm2. Design and draw the screw jack.The design should include the design of:(i) Screw (ii) Nut (iii) Handle and cup(iv) BodyAns. Refer Q. No. 4.45 in Unit 4.

UNIT-4

Q.1 Classify the rivets. What is throat of weld?Ans. Refer Q. No.5.21 & 5.2 in Unit 5.Q.2 Design a double riveted butt joint with two coverplates for the longitudinal seam of a boiler shell 1.5m in diameter subjected to a steam pressure of 0.95N/mm2. Assume joint efficiency as 75%, allowabletensile stress in the plate 90 MPa, compressivestress 140 MPa and shear stress in the rivet 56 MPa.Ans. Refer Q. No. 5.12 in Unit 5.Q.3 A bracket is riveted to a column by 6 rivets of equalsize. It carries a load of 100 KN at a distance of 250mm from the column if, 63MPa , find thediameter of the rivet.

Ans. Refer Q. No.5.18 in Unit 5.Q.4 A bracket carrying a load of 15 kN is to be welded asshown in figure. Find the size of the weld required ifthe allowable shear stress is not to exceed 80 MPa.

.


UNIT-5

Q.1 What are the materials for the shaft?Ans. Refer Q. No.3.1 in Unit 3.Q.2 A shaft supported on bearings 900 mm apart,receives power through a pulley of 450 mm

diameter, which over hangs the right bearing by200 mm. A shaft transmits power through a pulleyof 250 mm diameter, which is located mid – waybetween the bearings. The belt drives are at rightangle to each other. The ratio of tension in both the



belts is 3:1 and maximum tension in both the beltsis limited to 200 N. If the permissible tensile andshear stresses are 100 N/mm2 and 60 N/mm2respectively. Determine the diameter of shaft.

250 450

2BF

1BF

1AF2AF

Ans. Refer Q. No. 3.12 in Unit 3.Q.2 Design a cast iron protective type flange coupling totransmit 15 KW at 900 rpm from an electric motorto a compressor. The service factor may be assumedis 1.35. The following permissible stress may beused:

Shear stress for shaft, bolt and key material = 40MPaCrushing stress for bolt and key = 80 MPaShear stress for cast iron = 8 MPa:Ans. Refer Q. No. 2.37 in Unit 2

Apr-May 2010

UNIT-1

Q.1 Define factor of safety and notch sensitivity.Ans. Refer question 1.3 & 1.17 in Unit 1.Q.2 A cantilever beam made of cold drawn steel 20C8 issubjected to a completely reversed load of 10000 Nas shown. The notch sensitivity factor at the filletcan be taken as 0.85 and the expected reliability is90%. Determine the diameter d for the beam for alife of 10000 cycles in figure.

1000P N

.

Ans. Refer similar question 1.44 in Unit 1Q.3 A transmitting shaft of cold drawn steel C 30 issubjected to a fluctuating torque which varies from -100 Nm to +400 Nm. The factor of safety is 2 andthe expected reliability is 90%. Neglecting the effectof stress concentration, determine the diameter ofthe shaft. assume distortion energy theory of failure.Ans. Refer question 1.43 in Unit 1.Q.4 A blower is to run at 600 rpm. Power the blower isavailable from a motor rated at 8 kW at 1500 rpm.Design a chain drive for the system approximatecenter distance is 800 mm..Ans. Not in Syllabus.



UNIT-2

Q.1 What is the difference between key and splines.Ans. Refer Q. No.2.22 in Unit 2.Q.2 How do you accommodate the effect of keyway on ashaft?A standard spline connection 8 52 60 mm is usedfor the gear and the shaft assembly of a gear box in20 KW power at 300 rpm is transmitted by thesplines. The dimension of the splines are,

60 ,D mm d 52mm and 2P 6.5 / ,b N mm

0.06. Find:(i) The length of the hub of the gear(ii) The force required to shift the gear.Ans. Refer Q. No. 2. 3 & 2.4 in Unit 2.Q.3 Design a knuckle joint to transmit 150 KN, thedesign stress may be taken as 75 MPa in tension, 60MPa in shear and 150 MPa in compression.Ans. Refer Q. No.2.15,in Unit 2.

UNIT-3

Q.1 What is initial tension in a bolt, what I forcedeformation diagram for bolted joint?Ans. Refer Q. No.4.6 in Unit 4.Q.2 A casting weighing 30 KN is lifted by means of aneye bolt of 30 mm nominal diameter. The boltextends 40 mm into the casting. Determine thedirect tensile and shear stresses in the threadedportion of bolt.Ans. Refer Q. No. 4.19 in Unit 4.Q.3 A wall bracket is attached to a wall by means of fouridentical bolts, two at A and two at B as shown infigure. Assuming that the bracket is held against thewall and prevented from tipping about point C by allfour bolts and using an allowable tensile stress inthe bolts as 35 N/mm2, determine the size of thebolts on the basis of maximum principal stresstheory.

Ans. Refer Q. No.4.8 in Unit 4..Q.4 A screw jack is to lift a load of 80 KN through ahigher of 400 mm. The elastic strength of screwmaterial in tension and compression is 200 MPa andin shear 120 MPa. The material for the nut isphosphor-bronze for which the elastic limit may betaken as 100 MPa in tension, 90 MPa incompression and 80 MPa in shear. The bearingpressure between the nut and the screw is not toexceed 18 N/mm2. Design and draw the screw jack.The design should include the design of:(i) Screw (ii) Nut (iii) Handle and cup(iv) Body.Ans. Refer Q. No. 4.45 in Unit 4.

UNIT-4

Q.1 What are the modes of failure of a riveted joint?Ans. Refer Q. No. 5.4 in Unit 5.Q.2 A double riveted double cover butt joint in plates 20mm thick is made with 25 mm diameter rivets at100 mm pitch. The permissible stresses are:

120 , 100 , 150t cs MPa MPa MPa Find the efficiency of joint, taking the strength of therivet in the double strength of the rivet in thedouble shear as twice than that of the single shear.:Ans. Refer Q. No. 5.10 in Unit 5.



Q.3 Design a double riveted butt joint with two coverplates for the longitudinal seam of a boiler shell 1.5m in diameter subjected to a steam pressure of 0.95N/mm2. Assume joint efficiency as 75%, allowabletensile stress in the plate 90 MPa, compressivestress 140 MPa and shear stress in the rivet 56 MPa.Ans. Refer Q. No. 5.12 in Unit 5.Q.4 A rectangular steel plate is welded as a cantilever toa vertical column and supports single concentratedload P as shown in figure. Determine the weld size ifshear stress in the same is not to exceed 140 MPa. Ans. Refer Q. No. 5.29 in Unit 5.

UNIT-5

Q.1 How axles are different than shaft. What are therequirements for the shaft dewsign?Ans. Refer Q. No. 3.1 & 3.2 in Unit 3.Q.2 A transmission shaft supporting a spur gear B andthe pulley D. The shaft is mounted on two bearingsA and C. The diameter of the pulley an the pitchcircle diameters of the gear are 450 mm and 300mm respectively. The pulley transmits 20 KWpower at 500 rpm to gear P1 and P2 are belttensions in the tight and loose sides, while Pt and Prare tangential and radial components of gear toothforce. Assume, 0

1 23 tan 20 and r tP P P P The gearand pulley are keyed to the shaft. The material ofthe shaft is steel 50 C4 2 2700 / 460 / andut ytN mm N mm . Thefactors Kb and Kt of the ASME code are 1.5 each.Determine the shaft diameter using the ASME code.


Nov-Dec 2010

UNIT-1

Q.1 State distortion energy theorem of failure.Ans. Refer question 1.4 in Unit 1..Q.2 A non-rotating shaft supporting a load of 2.5KN asshown in figure 1.78. The shaft is made of brittlematerial with an ultimate tensile strength of

2300 /N mm . FOS 3FOS . Determine the diameterof shaft. .Ans. Refer question 1.38 in Unit 1..



Q.3 A cantilever beam made of cold drawn steel 2 240 8 600 / 380 /andut ytC S N mm S N mm asshown below. the force P acting at the free endvaries from 50 150 .N to N The expectedreliability is 90% and the FOS = 2. The notchsensitivity factor at the fillet is 0.9. Determine thediameter "d" of the beam at the fillet cross-section.

50 150P N N


Q.4 A blower is to run at 10 r.p.s, power to the blower isavailable from a motor rated at 8000 watts at 25r.p.s. Design a chain drive for the system of thecentre distance is to be 800 mm.Ans. Not in Syllabus

UNIT-2

Q.1 What are the different type of keys?Ans. Refer Q. No. 2.19 in Unit 2.Q.2 Design a cotter joint to withstand an axial loadvarying from 60LKN in tension to 60KN incompression. Allowable stresses fro the steel usedin the joint are 60 N/mm2 in tension, 75 N/mm2 incrushing & 48 N/mm2 in shearAns. Refer Q. No. 2.9 in Unit 2.Q.3 A knuckle joint is to transmit a force of 140,000 N.Allowable stresses in tension, shear andcompression are 75 N/mm2, 65 N/mm2, 64 N/mm2and 140 N/mm2 respectively. Design the joint.Ans. Refer Q. No. 2.15 in Unit 2.

Q.4 A standard splined connection mm is used for thegear and shaft assembly of a gearbox. The splinestransmit 20 kW power at 300 rpm. The dimensionsof splines are as follows:(i) Major diameter = 60 mm(ii) Minor diameter = 52 mm (iii) Number ofsplines = 8 permissible normal pressure onsplines is 6.5 N/mm2. The coef icient offriction is 0.06.Calculate:(i) Length of hub of the gear(ii) The force required for shifting the gear.Ans. Refer Q. No. 2.34. In Unit 2.

UNIT-3

Q.1 What are the types of threads of power screw?Ans. Refer question 4.22 in Unit 4.Q.2 An electric motor weighting 10 kN is lifted bymeans of an eye bolt. The eyebolt is screwed intothe frame of the motor. The eyebolt has coarsethreads. It is made up of plain carbon steel 30C8

2400 /ytS N mm and factor of safety is 6.Determine the size of bolt..Ans. Refer question 4.16 in Unit 4.Q.3 A steel plate subjected to a force of 5 kN and fixed toa channel by means of three identical bolts asshown in below figure. The bolts are made fromplain carbon steel 45C8 (Syt = 380 N/mm2)and thefactor of safety is 3. specify the size of bolt. Ans. Refer question 4.19 in Unit 4.



Q.4 A screw jack is to lift a load of 80 KN through ahigher of 400 mm. The elastic strength of screwmaterial in tension and compression is 200 MPa andin shear 120 MPa. The material for the nut isphosphor-bronze for which the elastic limit may betaken as 100 MPa in tension, 90 MPa incompression and 80 MPa in shear. The bearingpressure between the nut and the screw is not to

exceed 18 N/mm2. Design and draw the screw jack.The design should include the design of:(i) Screw (ii) Nut (iii) Handle and cup (iv)BodyAns. Refer question 4.45 in Unit 4.

UNIT-4

Q.1 What are the different types of riveted joints?Ans. Refer question 5.2 in Unit 5.Q.2 A double riveted double cover butt joint in plates 20mm thick is made with 25 mm diameter rivets at100 mm pitch. The permissible stresses are:

120 , 100 , 150t cs MPa MPa MPa Find the efficiency of joint, taking the strength of therivet in the double strength of the rivet in thedouble shear as twice than that of the single shear..Ans. Refer question 5.10 in Unit 5.Q.3 The bracket is to carry a load of 45 kN. Determinesize of the rivet, if the shear stress is not to exceed40 MPa. Assuming all rivets of the same size.

Ans. Refer question 4.17 in Unit 5.Q.4 Find the maximum shear stress induced in the weldof 6 mm size when a channel as shown in figure iswelded to a plate and loaded with 20 kN force at adistance 200 mm.

Ans. Refer question 5.33 in Unit 5..

UNIT-5

Q.1 What are the methods of design of shaft?Ans. Refer question 3.2 in Unit 3.Q.2 A solid shaft is supported on two bearings 1800 mmapart and rotates at 250 rpm. A 200 involute gear D,300 mm diameter is keyed to the shaft at a distanceof 150 mm to the left of the right hand bearing. Twopulleys B and C are located on the shaft at distances

of 600 mm and 1350 mm respectively to the right ofthe left hand bearing. The diameters of the pulleys Band C are 750 mm and 600 mm respectively. 40 H.P.is supplied to the gear, out of which 25 H.P. taken offin the pulley C and 15 H.P. from B. The drive from Bis vertically downward while from C the drive isdownward at an angle of 600 to the horizontal. Inboth cases tension ratio is 2 and the angle of lap is



1800. The combined fatigue and shock factors fortorsion an bending may be taken as 1.5 an 2.0respectively. Design a suitable shaft taking workingstress to be 42 N/mm2 in shear at 84 N/mm2 intension.Ans. Refer question 3.18 in Unit 3.Q.3 Design a C.I. flange coupling to transmit 150 H.P at250 rpm. The following permissible stresses may beusePermissible shear stress for shaft, bolt and keymaterial = 50 N/mm2 .

Permissible crushing stress for bolt and key = 150N/mm2Permissible shear stress for cast iron = 8 N/mm2.Ans. Refer Q. No. 2.37 in Unit 2..

.Apr-May 2011

UNIT-1

Q.1 Explain the following terms(i) Factor of safety(ii) Stress concentration factor.Ans. Refer question 1.3,1.17 in Unit 1.Q.2 A rectangular plate, 15 mm thick, made of a brittlematerial is shown in below figure 1.79. Calculate thestresses at each of three holes of 3, 5 and 10 mmdiameter.

3 5 10


Q.3 Design a roller chain to connect a 10 kW, 1500 rpmelectric motor to a centrifugal pump running at 750rpm.(i) Select a proper roller chain(ii) Calculate the pitch circle diameter of drivingand driven sprockets(iii) Determine the number of chain lnks.(iv) Specify the correct centre distance. Theconditions of operation are: Constant load,fixed centre distance, continuous lubrication,continuing running.During preliminary stages the centre distance canbe assumed to be 40 times the pitch of the chainAns. Not in Syllabus .

UNIT-2

Q.1 Explain the spline with neat sketch.Ans. Refer Q. No.2.1 in Unit 2.Q.2 Design a socket and spigot cotter joint to connecttwo steel rods of equal diameter. Each rod issubjected to an axial tensile force of 50 KN. Materialof two rods and cotter is steel 30C8 (Syt = 400 N/m2and Syc = 2Syt and Ssy = 0.5Syt) The factor of safety forrods, spigot end and socket end is assumed as 6while for cotter it is taken as 4.

Ans. Refer Q. No.2.13 &2.4 in Unit 2.Q.3 Design a knuckle joint to transmit 150 KN, thedesign stress may be taken as 75 MPa in tension, 60MPa in shear and 150 MPa in compression.Ans. Refer Q. No. 2.15 in Unit 2.



UNIT-3

Q.1 Explain the following:(i) Tap bolt (ii) StudSolve any one of the following [Either part (b) orpart (c)].Ans. Refer Q. No. 4.1 in Unit 4.Q.2 (i) A steel plate subjected to a force of 5 kN andfixed to a channel by means of three identicalbolts as shown in below figure. The bolts aremade from plain carbon steel 45C8 (Syt = 380N/mm2)and the factor of safety is 3. specifythe size of bolt.

(ii) A cast iron bracket, as shown in below figure.Support a load of 5 kN acting vertically at adistance of 250 mm from the face of column.THe bracket is fixed to steel column by meansof four identical bolts, two at A and two at B.The bolts are made of steel 40 C8 (Syt = 380N/m2) and factor of safety is 5. Determine themajor diameter of the bolts on the basis ofmaximum principal stress.

300mm

250mm 5 KNAB

C75mmAns. Refer Q. No. 4.8 in Unit 4.Q.3 Screw jack general purpose with a load carryingcapacity of 100 kN and maximum lifting height of350 mm. The screw jack is operated manually bytwo workers.

Assume factor safety = 5 Material for :(i) Screw and handle is plain carbon steel ofgrade 30C8 (Syt = 400 N/mm2,mm2, Syt = Syc, E= 2,07,000 N/mm2).(ii) Nut is cast variety of phosphor bronze ofgrade 1 (Sut = 190 N/mm2).Design the following component of screw jack:(1) Screw (2) Nut (3) HandleAns. Refer Q. No.4.45 in Unit 4.

UNIT-4

Q.1 Differentiate between permanent and temporaryjoint.Ans. Refer Q. No.5.1 in Unit 5.Q.2 What is martensite and Austenite and how it isformed?Ans. Refer Q. No. 5.14 in Unit 5.Q.3 A circular shaft, 50 mm in diameter, is welded to asupport by means of a fillet weld, as shown in belowfigure. Determine the size of the weld, if thepermissible shear stress in the weld is limited to100 N/mm2.

50

Ans. Refer Q. No. 5.32 in Unit 5..



UNIT-5

Q.1 Explain the difference between rigid and flexiblecouplingSolve any one of the following [Either part (b) orpart(c)].Ans. Refer Q. No. 2.28 in Unit 2.Q.2 Design a cast iron protective type flange coupling totransmit 15 KW at 900 rpm from an electric motorto a compressor. The service factor may be assumedis 1.35. The following permissible stress may beused:Shear stress for shaft, bolt and key material = 40MPaCrushing stress for bolt and key = 80 MPaShear stress for cast iron = 8 MPa..Ans. Refer Q. No. 2.37 in Unit 2.Q.3 The layout of an intermediate shaft of a gear boxsupporting two spur gears B and C. The shaft ismounted in two bearings A and D. The pitch circlediameters of gears B and C are 900 mm and 600 mmrespectively. The material of the shaft is steelFeE580 770 460 andut ytMPa MPa

1.5 2.0 andb tK K . Determine the shaft diameterusing the ASME code. Assume that the gears areconnected to the shaft by means of keys.

.


Nov-Dec 2011

UNIT-1

Q.1 Explain factor of safety and stress concentrationfactor.Ans. Refer question 1.3 & 1.17 in Unit 1.Q.2 Drawn S.N. curve for steel and explain:(i) Design for infinite life.(ii) Design for finite life..Ans. Refer question 1.22 & 1.23 in Unit 1.Q.3 A cantilever beam made of cold drawn steel

2 240 8 600 / 380 /andut ytC S N mm S N mm asshown below. the force P acting at the free endvaries from 50 150 .N to N The expected

reliability is 90% and the FOS = 2. The notchsensitivity factor at the fillet is 0.9. Determine thediameter "d" of the beam at the fillet cross-section.50 150P N N

.Ans. Refer question 1.44 in Unit 1.



Q.4 A compressor is to be actuated from a 10kW electricmotor. The speed of motor shaft is 970 rev/min andthat of the compressor is to be 330. The compressoroperates in two shift. The minimum centre distanceshould be 550 mm.(i) Specify the number of teeth on the driving anddriven sprockets.

(ii) Calculate the pitch circle diameter of drivingand driven sprockets.(iii) Select a proper roller chain.(iv) Determine the number of chain links.(v) Specify the correct centre distance.Ans. Not in Syllabus

UNIT-2

Q.1 What is the difference between key and splinesAns. Refer Q. No. 2.22 in Unit 2.Q.2 The standard cross-section for a flat key, which isfitted on a 50 mm diameter shaft, is 16 10mm . Thekey is transmitting 475 N-m torque from the shaftto the hub. The key is made of commercial steel

2230 /yt ycS S N mm Determine the length ofthe key. If the FOS = 3.Ans. Refer Q. No.2.33 in Unit 2.Q.3 Design an draw (sketch) a cotter joint to support aload varying from 30 kN in compression to 30 kN intension. The material used is carbon steel for whichthe following allowable stresses may be used. Theload is applied statically.Tensile stress = Compressive stresses = 50 MPa;

Shear stress = 35 MPa and Crushing stress = 90MPa.Ans. Refer Q. No. 2.8 in Unit 2..Q.4 It is required to design a knuckle joint to connecttwo circular rods subjected to an axial tensile forceof 50 KN. The rods are co-axial and a small amountof angular movement between their axes ispermissible. Design the joint and specify thedimensions of its components. Select a suitablematerial for the parts.Ans. Refer Q. No. 2.17 in Unit 2..

UNIT-3

Q.1 Differentiate between a bolt, tap bolt and stud.Ans. Refer Q. No. 4.1 in Unit 4.Q.2 A double threaded power screw with trapezoidalthread is used to raise a load of 300 kN. Thenominal diameter is 100 mm and the pitch is 12mm. The coefficient of friction and screw thread is0.15. Neglecting collar friction. Calculate:(i) Torque required to raise the load(ii) Torque required to lower the load(iii) Efficiency of the screw.

Ans. Refer Q. No. 4.36 in Unit 4.Q.3 A cast iron bracket, as shown in below figure.Support a load of 5 kN acting vertically at a distanceof 250 mm from the face of column. The bracket isfixed to steel column by means of four identicalbolts, two at A and two at B. The bolts are made ofsteel 40 C8 (Syt = 380 N/m2) and factor of safety is 5.Determine the major diameter of the bolts on thebasis of maximum principal stress.

300mm

250mm 5 KNAB

C75mmAns. Refer Q. No. 4.8 in Unit 4.Q.4 A screw jack suitable to lift a maximum load of 50kN through a height of 200 mm, is to be designedwith the following data:(i) Allowable stress for screw and handle, Tensilestress = 90 N/mm2, compressive stress = 110N/mm2, Shearing stress = 60 N/m2.



Allowable bearing pressure between nut and screw16N/mm2, coefficient of friction of threads andcollar may be taken as 0.14 Design: (i) Screw (ii) Nut (iii) Handle .

Ans. Refer Q. No. 4.45 in Unit 4UNIT-4

Q.1 List the types of welded joint.Ans. Refer Q. No. 5.21 in Unit 5.Q.2 Find the efficiency of single reveted lap joint of 6mm plate with 20 mm diameter rivets having apitch of 50 mm. The permissible stresses are:Tensile, stress in plate = 100 MPa,Shearing stress in rivets = 80 MPaCrushing stress in rivets = 160 MPa.Ans. Refer Q. No. 5.13 in Unit 5.Q.3 Design a double riveted butt joint with two coverplates for the longitudinal seam of a boiler shell 1.5m in diameter subjected to a steam pressure of 0.95N/mm2. Assume joint efficiency as 75%, allowabletensile stress in the plate 90 MPa, compressivestress 140 MPa and shear stress in the rivet 56 MPaAns. Refer Q. No. 5.12 in Unit 5..

Q.4 A circular shaft, 50 mm in diameter, is welded to asupport by means of a fillet weld, as shown in belowfigure. Determine the size of the weld, if thepermissible shear stress in the weld is limited to100 N/mm2.50

.

Ans. Refer Q. No. 5.32 in Unit 5.UNIT-5

Q.1 Differentiate between shaft and axle.Ans. Refer Q. No. 3.1 in Unit 3.Q.2 What is meant by term high carbon steel?Ans. Refer Q. No. 3.8 in Unit 3.Q.3 Two 35 mm shaft are connected by a flangedcoupling. The flanges are fitted with 6 bolts on 125mm pitch circle diameter of bolts. The shaft

transmit a torque of 800 N-m at 300 rpm. For thesafe stresses mentioned below calculate:(i) Diameter of bolts (ii) Thickness of flanges(iii) Key dimensions (iv) Hub length and(v) Power transmittedAns. Refer Q. No. 2.30 in Unit 2.

Apr-May 2012

UNIT-1

Q1. How will you designate the following varieties ofmaterials:(i) Grey cast iron with an ultimate tensilestrength of 300 N/mm2.(ii) Plain carbon steel with 0.4% carbon and 0.8% manganese.Ans. (i) GCI-25, (ii) C-40 or C-45.Q.2 State:(i) Maximum normal stress theory(ii) Maximum shear stress theory.Ans. Refer question 1.4 in Unit 1.

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6-22|MACHINEDESIGN- I


Q.3 A long straight tube, 76 mm internal diameter and2.5 mm thick is subjected to an internal pressure of5.6 N/mm2. Consider it as a thin cylinder. IF thetube is subjected to a twisting moment of 70 Nm,Elastic limit stress = 282 N/mm2, determine thefactors of safety on(i) Maximum principal stress theory(ii) Maximum shear stress theory(iii) Distortion energy theoryAns. Refer question 1.4 in Unit 1.Q.4 Design a chain drive to transmit 10 kW from anelectric motor running at 1440 rpm to a centrifugal

pump running at 720 rpm. The service conditioninvolve moderate shocks.(i) Select a proper roller chain and give a list ofits dimensions(ii) Determine the pitch circle diameters ofdriving and driven sprockets(iii) Determine the number of chain links(iv) Specify the correct centre distance betweenthe axes of sprockets.Ans. Not in Syllabus.

UNIT-2

Q1. Write the function of key and name them.Ans. Refer Q. No.2.19 in Unit 2.Q.2 Briefly write different types and applications of acotter joint. Differentiate between a cotter and akey.Ans. Refer Q. No. 2.2 in Unit 2.

Q.3 Design a cotter joint for carrying an axial load of 10kN..Ans. Refer Q. No.2.20 in Unit 2.Q.4 Design a knuckle joint to connect two tension rodssubjected to an axial load of 15 kN.Ans. Refer Q. No.2.18 in Unit 2.

UNIT-3

Q1. What is a power screw and state its applications.

Ans. Refer Q. No. 4.20 in Unit 4.Q.2 Write any four forms of threads and briefly explain.Ans. Refer Q. No.4.22 in Unit 4.Q.3 The lead screw of a lathe has trapezoidal threads.To drive the tool carriage the screw has to exert anaxial force of 20 kN. The thrust is carried by thecollar. The length of the lead screw is 1.5 m.Coefficient of friction at the collar and nut are 0.1and 0.15 respectively. Suggest suitable size of screwand height, of the nut if the permissible bearingpressure is 4 MPa. Check for maximum shear stressAns. Refer Q. No 4.50 in Unit 4.Q.4 A bracket is itted to a vertical channel with 5 bolts,three at the top and two at the bottom with all thebotls equally spaced. The value of P = 20 kN, e = 200mm. 1l = 50 mm and 2l = 250 mm.

1l

2l


UNIT-4

Q.1 What are the various modes in which a riveted jointmay fail?Ans. Refer Q. No. 5.4 in Unit 5. Q.2 A triple riveted lap joint is to be made between 6.5mm plates. The allowable stress

2 2 235 / , 29 / , 52.50 /t s cf N mm f N mm f N mm



Calculate the rivet diameter, rivet pitch and backpitch, zig-zag riveting is to be used. Indicate how thejoint will fail..Ans. Refer Q. No. 5.11 in Unit 5.Q.3 Determine the size, of the weld required for staticloading in the eccentrically loaded weld as shown inbelow figure… The effective length of the weld is12.5 mm shorter than the weld to allow for startingand stopping of the weld .


Q.1 Why is it essential to use coupling? What are theirdifferent types?.Ans. Refer Q. No. 2.23 in Unit 2.Q.2 Differentiate between shaft and axle. What are thecauses of failure of shaft?Ans. Refer Q. No.3.1 & 3.3 in Unit 3.Q.3 Design a muff coupling which is used to connect twosteel shafts transmitting 25 KW power at 360 rpm.The shaft and key are made of plain carbon steel30C8 2400 /yt ycS S N mm The sleeve is made

up of grey cast-iron FG200 2200 /utS N mm FOSfor shaft and key is 4. For sleeve, the FOS = 6 basedon ultimate strength.Ans. Refer Q. No. 2.29 in Unit 2.

Nov-Dec 2012

UNIT-1

Q1. Define stress concentration factor?.Ans. Refer question 1.17 in Unit 1.Q.2 A flat plate subjected to a tensile force of 5 KN isshown. The plate material is grey cast iron 200FGand 2.5FOS . Determine the thickness of theplate.

Ans. Refer question 1.35 in Unit 1.Q.3 It is required to design a chain drive with power 15HP, motor speed 97 r.p.m, compressor speed 350

rpm, center distance 550 mm, chain is adjustable,working condition 8 hr per day. Design a chain interms of:(i) Specify the number of teeth of the driving &driven sprockets(ii) Determine the number chain links(iii) Specify the correct center distance betweenaxis.(iv) Select a proper roller chain(v) Calculate the pitch circle diameter of driving &driven sprockets.Ans. Not in Syllabus.



UNIT-2

Q1. What is the difference between key & splines?.Ans. Refer Q. No.2.22 in Unit 2.Q.2 Design a cotter joint to support a load varying 30 kNin compression to 30 kN in tension. The materialused is carbon steel for which the followingallowable stress may be used. The load is appliedstatically. Tensile stress =Compressive stress = 50MPa, shear stress = 35 MPa and crushing stress = 90MPa

Ans. Refer Q. No.2.8 in Unit 2.Q.3 Design a knuckle joint to transmit 150 KN, thedesign stress may be taken as 75 MPa in tension, 60MPa in shear and 150 MPa in compressionAns. Refer Q. No. 2.15 in Unit 2.

UNIT-3

Q1. What are the types of threads for power screws?Ans. Refer Q. No.4.22 in Unit 4.Q.2 The lead screw of a lathe has has Acme threads of50 mm outside diameter and 8 mm pitch the screwmust exert an axial pressure of 2500 N in order todrive the total carrieage. The thrust is carried on acollar 110 mm outside diameter and 55mm insidediameter and the lead screw rotate at 30 rpm.Determine (a) The power required to drive thescrew and (b) The efficiency of the lead screw.Assume a coefficient of friction of 0.15 for the screwand 0.12 for collar.

Ans. Refer Q. No.4.35 in Unit 4.Q.3 A steel plate subjected to a force of 3 KN and fixedto a vertical channel by means of four identical boltsas shown. THe bolts are made of plain carbon steel45C8 with 2380 /yt N mm If FOS = 2. Determinethe diameter of bolts.


UNIT-4

Q.1 Define the efficiency of riveted joint.Ans. Refer Q. No. 5.4 in Unit 5.Q.2 A double riveted lap joint with zigzag riveting is tobe designed for 13 mm thick plates assume

80 ,t MPa 60 , 120cMPa MPa State howthe joint will fail and find the efficiency of the joint.Ans. Refer Q. No.5.34 in Unit 5.Q.3 A welded connection of steel plates, as shown infigure… is subjected to an eccentric force of 10 kN.Determine the throat dimension of the weld if thepermissible shear stress is limited to 95 N/mm2.Assume static condition.

.




UNIT-5

Q.1 Differentiate between shaft & axle.Ans. Refer Q. No.3.1 in Unit 3.Q.2 Design a shaft to transmit power from an electricmotor to a lathe head stock through a pulley bymeans of a belt drive. The pulley weighs 200N andis located at 300 mm from the center of bearing. Thediameter of the pulley is 200 mm and the maximumpower transmitted is 1 kW at 120 rpm. The angle oflap of the belt is 1800coefficent of friction betweenthe belt 7 the pulley is 0.3. The shock and fatiguefactors for bearing twisting are 0.5 and 2.0respectively. The allowable shear stress in the shaftmay be taken as 35 MPaAns. Refer Q. No. 3.17 in Unit 3.Q.3 Design a muff coupling which is used to connect twosteel shafts transmitting 40 KW at 350 r.p.m. Thematerial for the shaft and key is plain carbon steelfor which allowable shear and crushing stress may

be taken as 40 MPa and 80 MPa respectively. Thematerial for the muff is cast iron for which theallowable shear stress may be assumed as 15 MPa.Ans. Refer Q. No. 2.29 in Unit 2.

Apr-May 2013

UNIT-1

Q.1 Define:(i) Stress concentration(ii) Notch sensitivity .Ans. Refer Q. No. 1.3 & 1.17 in Unit 1.Q.2 A cantilever beam made of cold drawn steel

2 240 8 600 / 380 /andut ytC S N mm S N mm as

shown below. the force P acting at the free endvaries from 50 150 .N to N The expected

reliability is 90% and the FOS = 2. The notchsensitivity factor at the fillet is 0.9. Determine thediameter "d" of the beam at the fillet cross-section.

50 150P N N

Ans. Refer question 1.44 in Unit 1.Q.3 Design a roller chain drive to connect a 15 kW, 1500rpm electric motor to a centrifugal pump running at750 rpm. The conditions of operation are constantload, fixed center distance, continuous lubrication,continuous running.Ans. Not in syllabus

UNIT-2

Q.1 List the various function of keys.Ans. Refer Q. No.2.19 in Unit 2. Q.2 Design a joint to connect two rods of equal diameterto resist a tensile load of 60 kN. All parts of the jointare made of same material.



Allowable stresses60 , 70 , 125t cMPa MPa MPa .

Ans. Refer Q. No. 2.14 in Unit 2.Q.3 Design a cotter joint to support a load varying 30 kNin compression to 30 kN in tension. The materialused is carbon steel for which the followingallowable stress may be used. The load is applied

statically. Tensile stress =Compressive stress = 50MPa, shear stress = 35 MPa and crushing stress = 90MPa.Ans. Refer Q. No. 2.8 in Unit 2.

UNIT-3

Q.1 What is the difference between a rivet and a bolt.

Ans. Refer Q. No. 4.1 in Unit 4.Q.2 A wall bracket is attached to a wall by means of fouridentical bolts, two at A and two at B as shown infigure. Assuming that the bracket is held against thewall and prevented from tipping about point C by allfour bolts and using an allowable tensile stress inthe bolts as 35 N/mm2, determine the size of thebolts on the basis of maximum principal stresstheory.

Ans. Refer Q. No.4.8 in Unit 4.Q.3 A power screw having double start square thread of25 mm nominal diameter and 5 mm pitch is actedupon by an axial load of 10 kN. The outer and innerdiameters of screw collar are 50 mm and 20 mm.The coefficient of thread friction and collar frictionmay be 0.2 and 0.15. The screw rotates at 12 rpm,allowable thread bearing pressure is 5.8 MPa. Find:(i) Torque required (ii) Stress in screw (iii)Design the screw for ASME codeAns. Refer question 4.48 in Unit 4.

UNIT-4

Q.1 What is a throat and legt in case of weld? Weld?What is the relation between them?Ans. Refer Q. No. 5.21 in Unit 5.Q.2 A rectangular steel plate is welded as a cantilever toa vertical column and supports single concentratedload P as shown in figure. Determine the weld size ifshear stress in the same is not to exceed 140 MPa.

.

Ans. Refer Q. No. 5.29 in Unit 5.Q.3 Design a double riveted butt joint with two coverplates for the longitudinal seam of a boiler shell 1.5m in diameter subjected to a steam pressure of 0.95N/mm2. Assume joint efficiency as 75%, allowabletensile stress in the plate 90 MPa, compressivestress 140 MPa and shear stress in the rivet 56 MPaAns. Refer Q. No. 4.12 in Unit 4.Q.4 Sketch and explain TTT curve for a specificcomposition of steel.Ans. Refer Q. No.4.5 in Unit 4.



UNIT-5

Q.1 What is strength, rigidity & stiffnes in design ofshaft.Ans. Refer Q. No. 3.2 in Unit 3.Q.2 A transmission shaft supporting a spur gear B andthe pulley D. The shaft is mounted on two bearingsA and C. The diameter of the pulley an the pitchcircle diameters of the gear are 450 mm and 300mm respectively. The pulley transmits 20 KWpower at 500 rpm to gear P1 and P2 are belttensions in the tight and loose sides, while Pt and Prare tangential and radial components of gear toothforce. Assume, 0


Ans. Refer Q. No. 3.21 in Unit 3.Q.3 Design a muff coupling which is used to connect twosteel shafts transmitting 25 KW power at 360 rpm.The shaft and key are made of plain carbon steel30C8 2400 /yt ycS S N mm The sleeve is madeup of grey cast-iron FG200 2200 /utS N mm FOSfor shaft and key is 4. For sleeve, the FOS = 6 basedon ultimate strengthAns. Refer Q. No. 2.29 in Unit 2.

Nov-Dec 2013

UNIT-1

Q.1 State(i) Maximum normal stress theory(ii) Stress concentration factorAns. Refer question 1.4 & 1.17 in Unit 1.Q.2 A cantilever beam made of cold drawn steel

2 240 8 600 / 380 /andut ytC S N mm S N mm asshown below. the force P acting at the free endvaries from 50 150 .N to N The expectedreliability is 90% and the FOS = 2. The notchsensitivity factor at the fillet is 0.9. Determine thediameter "d" of the beam at the fillet cross-section.

50 150P N N

.Ans. Refer question 1.44 in Unit 1.Q.3 A rectangular plate, 15 mm thick, made of a brittlematerial is shown in below figure 1.79. Calculate thestresses at each of three holes of 3, 5 and 10 mmdiameter.



3 5 10

Or(ii) A rotating bar made of steel 245 8 630 /utC S N mm is subjected to acompletely reversed bending stress. Thecorrected endurance limit of the bar is

2315 /N mm . Calculate the figure strength ofthe bar for a life of 90000 cyclesAns. Refer question 1.36 & 39 in Unit 1.

Q.4 Design a roller chain drive to connect a 15 kW 1500rpm electric motor to a centrifugal pump running at750 rpm. THe service conditions involve moderateshocks.(i) Select a proper roller chain and give a list ofits dimensions.(ii) Determine the pitch circle diameter of drivingand driven sprockets(iii) Determine the number of chain links(iv) Recommend the correct centre distancebetween the axes of the sprocketsThe conditions of operations are: Constant load,Fixed centre distance, Continuous lubrication,Continuous running.Ans. Not in syllabus

UNIT-2

Q.1 What are the different types of key? Enumerate thefunctions of keysAns. Refer Q. No. 2.19 in Unit 2.Q.2 Design a knuckle joint for a tie rod of a circularsection to sustain maximum pull of 70 KN. THeultimate tensile strength and shearing strength ofthe pin material are 510 MPa and 396 MParespectively. Determine the tie rod section and thepin section. Take FOS=6. ut (for rod) = 420 MPa..Ans. Refer similar Q. No. 2.16 in Unit 2.

Q.3 Design a socket and spigot cotter joint to connecttwo steel rods of equal diameter. Each rod issubjected to an axial tensile force of 50 KN. Materialof two rods and cotter is steel 30C8 (Syt = 400 N/m2and Syc = 2Syt and Ssy = 0.5Syt) The factor of safety forrods, spigot end and socket end is assumed as 6while for cotter it is taken as 4...Ans. Refer Q. No.2.10 in Unit 2.

UNIT-3

Q.1 (i) What are the types of threads of powerscrew?(ii) What is initial tension in a bolt, what is forcedeformation diagram for bolted, joint?Ans. Refer Q. No. 4.4 & 4.6 in Unit 4.Q.2 A screw jack is to lift a load of 80 KN through ahigher of 400 mm. The elastic strength of screwmaterial in tension and compression is 200 MPa andin shear 120 MPa. The material for the nut isphosphor-bronze for which the elastic limit may betaken as 100 MPa in tension, 90 MPa incompression and 80 MPa in shear. The bearingpressure between the nut and the screw is not toexceed 18 N/mm2. Design and draw the screw jack.The design should include the design of:(i) Screw (ii) Nut (iii) Handle and cup

(iv) Body.Ans. Refer Q. No. 4.45 in Unit 4.Q.3 A steel plate subjected to a force of 3 KN and fixedto a vertical channel by means of four identical boltsas shown. The bolts are made of plain carbon steel45C8 with 2380 /yt N mm If FOS = 2. Determinethe diameter of bolts.



Ans. Refer similar Q. No. 4.4 in Unit 4.Q.4 A bolted joint is used to connect two components.The combined stiffness of the two components istwice the stiffness of bolt. The initial tightening ofnut results in a pre-load of 5 kN in the bolt. Theexternal force of 10 kN creates further tension inbolt. The bolt is made of plain carbon steel 30C8with yield point stress in tension = 400 N/mm2 andfactor of safety is 3. There are coarse threads on thebolt. Determine the size of boltAns. Refer Q. No. 4.17 in Unit 4.

UNIT-4

Q.1 Find the efficiency of single reveted lap joint of 6mm plate with 20 mm diameter rivets having apitch of 50 mm. The permissible stresses are:Tensile, stress in plate = 100 MPa,Shearing stress in rivets = 80 MPaCrushing stress in rivets = 160 MPaAns. Refer question 5.13 in Unit 5Q.2 Design a double riveted butt joint with two coverplates for the longitudinal seam of a boiler shell 1.5m in diameter subjected to a steam pressure of 0.95N/mm2. Assume joint efficiency as 75%, allowabletensile stress in the plate 90 MPa, compressivestress 140 MPa and shear stress in the rivet 56 MPaAns. Refer question 5.12 in Unit 5.Q.3 A welded connection of steel plates, as shown infigure… is subjected to an eccentric force of 10 kN.Determine the throat dimension of the weld if thepermissible shear stress is limited to 95 N/mm2.Assume static condition.

.Ans. Refer question 5.30 in Unit 5Q.4 A steam boiler is to be designed for a workingpressure of 2.5 N/mm2 with its inside diameter 1.6m. Give the design calculations for the longitudinaland circumferential joints for the following workingstresses for steel plates and rivets:In tension = 75 MPa, In shear = 60 MPa, In crushing= 125 MPa.Ans. Refer question 5.16 in Unit 5.

UNIT-5

Q.1 Differentiate between a shaft and an axle. What arethe causes of failure of shaft?Ans. Refer Q. No. 3.1 in Unit 3.Q.2 Design a rigid muff coupling. Use CI. material for themuff. The power transmitted is 25 kW at 300 rpm.Ultimate tensile strength = 200 MPa and factor ofsafety = 6. Use 30C8 steel for the shaft considered.Yield point stress = 330 MPa and factor of safety = 4.Ans. Refer similar Q. No.2.29 in Unit 2.Q.3 Design a cast iron protective type flange coupling totransmit 15 KW at 900 rpm from an electric motorto a compressor. The service factor may be assumed

is 1.35. The following permissible stress may beused:Shear stress for shaft, bolt and key material = 40MPaCrushing stress for bolt and key = 80 MPaShear stress for cast iron = 8 MPa.Ans. Refer Q. No. 3.37 in Unit 2.Q.4 A machined surface shaft carries a completelyreversed bending moment of 3 kN-m and a torqueof 10.8 kN-m. The stress concentration factor forbending and torsion is 1.35. Take factor of safety =2.0. The ultimate strength of material

2825 /u N mm ; yield strength 2610 /yt N mm .



Calculate the diameter of shaft based on maximumshear stress theory of failure. Neglect notchsensitivity.Ans. Refer Q. No. 3.16 in Unit 3.

Apr-May 2014

UNIT-1

Q.1. Explain the following terms:(i) Design stress (ii) Factor of safetyAns. Refer question 1.3 in Unit 1.Q.2 A transmission shaft made of steel 20C8 (Sut = 440N/mm2) is subjected to reversed torsional moment.The shaft diameter is 30 mm and the expectedreliability is 95%. There is a step in the shaft, atwhich the theoretical stress concentration factor is1.8 while the notch sensitivity factor is 0.86Determine the endurance limit for reversedtorsional moment, using the distortion energytheory.Ans. Refer question 1.40 in Unit 1.Q.3 A cantilever beam made of cold drawn steel

2 240 8 600 / 380 /andut ytC S N mm S N mm asshown below. the force P acting at the free endvaries from 50 150 .N to N The expectedreliability is 90% and the FOS = 2. The notchsensitivity factor at the fillet is 0.9. Determine thediameter "d" of the beam at the fillet cross-section.

50 150P N N

Ans. Refer question 1.44 in Unit 1.Q.4 It is required to design a chain drive with a douplexchain to connect a 15 kW, 1400 rpm electric motorto a transmission shaft running at 350 rpm. Theoperation involves moderate shocks.(i) Specify the number of teeth on the driving anddriven sprockets.(ii) Select a proper roller chain.(iii) Calculate the pitch circle diameters of thedriving and driven sprockets.(iv) Determine the number of chain links.(v) Specify the correct centre distance.During preliminary stages, the centre distance canbe assumed to be 40 times the pitch of the chain.Ans. Not in Syllabus

UNIT-2

Q.1 Prove that a square key is equally strong in shearand compression.Ans. Refer Q. No. 2.16 in Unit 2.Q.2 Design a knuckle joint for a tie rod of a circularsection to sustain maximum pull of 70 KN. Theultimate tensile strength and shearing strength ofthe pin material are 510 MPa and 396 MParespectively. Determine the tie rod section and thepin section. Take FOS=6. ut (for rod) = 420 MPa.

Ans. Refer Q. No. 2.16 in Unit 2.Q.3 Design a joint to connect two rods of equal diameterto resist a tensile load of 60 kN. All parts of the jointare made of same material.Allowable stresses

60 , 70 , 125t cMPa MPa MPa .Ans. Refer Q. No.2.14 in Unit 2.



UNIT-3

Q.1. Explain collar friction.Ans. Refer Q. No.4.23 in Unit 4.Q.2 A sluice valve used in water-pipelines, consist of agate raised by the spindle, which is rotated by thehand wheel. The spindle has single-start squarethreads. The nominal diameter is 36 mm, and thepitch is 6 mm. The inner and outer diameters of thefriction collar are 30 mm and 50 mm respectively.The coefficients of friction at the threads and thecollar are CI. 15 and 0.20 respectively. The weight ofthe gate is 7.5 kN, and the frictional resistance toopen the valve due to water pressure is 2.5 kN.Using the uniform wear theory for collar friction,calculate:(i) The torque required to raise the gate and(ii) The overall efficiency of the mechanismAns. Refer similar Q. No. 4.42 in Unit 4.Q.3 The structural connection shown in figure issubjected to an eccentric force P of 10 kN with aneccentricity of 500 mm. The centre – distancebetween bolts 1 and 2 is 200 mm, and the centre –

distance between bolts 1 and 3 is 150 mm. All thebolts are identical. The bolts are made from plaincarbon steel 30C8 (Syt = 400 N/mm2) and factor ofsafety is 2.5. Determine the size of the bolts

Ans. Refer similar Q. No. 4.12 in Unit 4UNIT-4

Q.1. Define the efficiency of riveted joint.Ans. Refer question 5.4 in Unit 5Q.2 Design a double riveted butt joint with two coverplates for the longitudinal seam of a boiler shell 1.5m in diameter subjected to a steam pressure of 0.95N/mm2. Assume joint efficiency as 75%, allowabletensile stress in the plate 90 MPa, compressivestress 140 MPa and shear stress in the rivet 56 MPa.Ans. Refer question 5.12 in Unit 5.Q.3 A rectangular cross-section bar is welded to asupport by means of fillet weld as shown in figure.Determine the size of the welds if the permissibleshear stress in the weld is limited to 75 MPa. 50 mm

Ans. Refer question 5.27 in Unit 5UNIT-5

Q.1 Define angle of twist.Ans. Refer Q. No. 3.2 in Unit 3. Q.2 A transmission shaft, supporting two pulleys A andB an mounted between two bearings C1& C2 asshown in figure. Power is transmitted from pulley A



to B, the shaft is made of plain carbon steel 45 C8( 2600 /uts N mm and 2380 /yt N mm ) Thepulleys are keyed to the shaft. Determine the shaftdiameter using the ASME code, if 1.5& 1.0b tK K .

200

300

Ans. Refer Q. No. 3.22 in Unit 3.Nov-Dec 2014

UNIT-1

Q.1 Define factor of safety. Give a guidelines forselection of factor of safety.Ans. Refer question 1.3 in Unit 1.Q.2 A plate, 10 mm thick subjected to a tensile load of20 kN shown in figure. The plate is made of cast iron

2350 /ut N mm and the factor of safety is 2.5.Determine the fillet Radius

Ans. Refer question 1.31 in Unit 1.Q.3 A component machined from a plate made of steel

45 8C 2630 /utS N mm is shown in figure. It is

subjected to a completely reversed axial force of50 KN . The expected reliability is 90% and

2FOS . The size factor is 0.85 . Determine theplate thickness "t" for infinite life, if notchsensitivity factor is 0.8.50P kN

5r

50P kN

Ans. Refer question 1.37 in Unit 1.Q.4 A cantilever beam of cold drawn steel 20C8

2540 /utS N mm is subjected to a completelyreversed load of 10000N. The notch sensitivityfactor 0.85q and expected reliability is 90%.Determine the diameter “d” for the beam for a life of1000 cycles..



1000P N

.


UNIT-2

Q.1 What are the different types of keys?Ans. Refer Q. No.2.19 in Unit 2.Q.2 Design and draw a socket and spigot cotter joint.Support a load varying from 10 kN in tension tocompression. The material used is steel permissiblestresses are:Tensile stress 250 / ,t N mm 235 / ,N mm

290 / isc N mm

Ans. Refer Q. No.2.10 in Unit 2.Q.3 A rigid coupling is used to transmit 20 kW power at720 rpm. There are four bolts and the pitch circledia of bolt is 125 mm. The bolts are made of

245 380 /utC N mm and F.O.S is 3. Design thecoupling.Ans. Refer Q. No.2.43, 2.36 in Unit 2.

UNIT-3

Q.1 Define shaft. What is the difference between shaftand axleAns. Refer Q. No.3.1 in Unit 3.Q.2 A line shaft supporting two pulleys A and B. Poweris supplied to the shaft by means of a vertical belt onthe pulley A, which is then transmitted to the pulleyB carrying a horizontal belt. The ratio of belt tensionon tight and loose sides is 3:1. The limiting value oftension in the belts is 2.7 KN. The shaft is made ofplain carbon steel 40C8, Sut = 650 N/mm2 and Syt =380 N/mm2. The pulleys are keyed to the shaft.Determine the diameter of the shaft according tothe ASME code, if

1.5& 1.0b tK K

450 450 2501 A 2 B250

450

P4

P3

P1 P2


Q.1 What are the different types of power threads.Ans. Refer question 4.22 in Unit 4.Q.2 A cast iron bracket fixed to the steel structure isshown in figure (a). It supports a load P of 25 kN.

There are two bolts at A and two bolts at B. Thedistances are as follows.1 250 , 200 , 400l mm l mm l mm Determine the rise of the bolts, if maximumpermissible tensile stress in the bolt is 50 N/mm2



1l

2l

.Ans. Refer question 4.14 in Unit 4.Q.3 A screw jack is to lift a load of 80 KN through ahigher of 400 mm. The elastic strength of screw

material in tension and compression is 200 MPa andin shear 120 MPa. The material for the nut isphosphor-bronze for which the elastic limit may betaken as 100 MPa in tension, 90 MPa incompression and 80 MPa in shear. The bearingpressure between the nut and the screw is not toexceed 18 N/mm2. Design and draw the screw jack.The design should include the design of:(i) Screw (ii) Nut (iii) Handle and cup(iv) Body.Ans. Refer similar question 4.45 in Unit 4.

UNIT-5

Q.1 What is the strength of a riveted joint.Ans. Refer Q. No. 5.4 in Unit 5Q.2 A steam boiler is to be designed for a workingpressure of 2.5 N/mm2 with its inside diameter 1.6m. Give the design calculations for the longitudinaland circumferential joints for the following workingstresses for steel plates and rivets:In tension = 75 MPa, In shear = 60 MPa, In crushing= 125 MPa..Ans. Refer Q. No. 5.16 in Unit 5Q.3 The bracket is to carry a load of 45 kN. Determinesize of the rivet, if the shear stress is not to exceed40 MPa. Assuming all rivets of the same size.DEC 2014, 10

Ans. Refer Q. No.5.17 in Unit 5.Q.4 A bracket carrying a load of 15 kN is to be welded asshown in figure. Find the size of the weld required ifthe allowable shear stress is not to exceed 80 MPa.




UNIT-3

Q.1 Define centrifugal clutch.Ans. Refer Q. No.3.37 Unit 3.Q.2 A single dry plate clutch is to be designed totransmit 7.5 kW at 900 rpm. Find :(i) Diameter of shaft.(ii) Mean radius and face width of the frictionlining assuming , the ratio of mean radius toface width as 4.(iii) Outer and inner radii of the clutch plate.(iv) Dimensions of spring, assuming that thenumber of springs are 6 and spring index 6.The allowable shear for the spring wire willmay be taken as 420 MPa.Ans. Refer Q. No.3.7 & 3.9 in Unit 3.Q.3 The layout of a two stage 20 kW V belt speedreduction is shown below. The first stage consists ofa 120 mm diameter engine-driven input pulleyrotating at 2400 rpm and driving a 400 mmdiameter pulley mounted on an intermediate shaft.The 200 mm diameter small pulley of the secondstage is also mounted on this intermediate shaft anddrives 360 mm diameter out pulley connected tothe load. Tensions are indicated on the sketch.Design the intermediate shaft abcd. Design stress betaken as 25 MPa.

16.60 3535 N547 N

990 N1820 N

17.10

125

400

630

Intermediate shaft preliminary layout

Ans. V belt is out of syllabus.UNIT-4

Q.1 What do you understand by sing start and doublestart threads?Ans. Refer question 4.2 in Unit 4.Q.2 A pillar crane having a circular base of 600 mmdiameter is fixed to the foundation of concrete baseby means of four bolts. The bolts are of size 30 mmand are equally spaced on a bolt circle diameter of500 mm. Determine : The distance of the load fromthe centre of the pillar along a line XX as shown infigure. The load lifted by the pillar crane is 60 kNand allowable tensile stress for bolt material is 60MPa.

1L

2L

Ans. Referquestion 4.15 in Unit 4.



Q.3 Write short notes on the following(i) Power threads(ii) Efficiency of thread(iii) Self-locking of threadsAns. Refer question 4.20 and 4.24 in Unit 4.Q.4 A power screw having double start square thread of25 mm nominal diameter and 5 mm pitch is actedupon by an axial load of 10 kN. The outer and inner

diameters of screw collar are 50 mm and 20 mm.The coefficient of thread friction and collar frictionmay be 0.2 and 0.15. The screw rotates at 12 rpm,allowable thread bearing pressure is 5.8 MPa. Find:(i) Torque required(ii) Stress in screw(iii) Design the screw for ASME codeAns. Refer question 4.46 in Unit 4.UNIT-5

Q.1 What are the different types of welded joints?Ans. Refer Q. No.5.21 in Unit 5.Q.2 Design a double riveted butt joint with two coverplates for the longitudinal seam of a boiler shell of0.75 m diameter. To carry a maximum steampressure of 1.05 kN/mm2. The allowable stresses intension crushing and shear are 35 N/mm2, 52.5N/mm2 and 28 N/ mm2. The efficiency of it isbetween 70% to 75%.Ans. Refer Q. No.5.14 in Unit 5.

Q.3 Derive an expression for a welded joint subjected toan eccentric loading, load is perpendicular to planeof weld.Ans. Refer Q. No. 5.24 in Unit 5.Q.4 A double riveted lap joint is to be made between 9.5m plates. IF the safe working stresses are

2 280 / , 60 /r sN mm N mm and 1.5 ,c t calculate the rivet pitch, the distance between rowsof rivets for the joint. State how the joint will fail.Ans. Refer Q. No. 5.34 in Unit 5.

Nov-Dec 2015

UNIT-1

Q.1 Define stress concentration and state how its effectis considered.Ans. Refer question 1.17 in Unit 1.Q.2 A rotating shaft, subjected to a non-rotating force of5 kN and simply supported between two bearings Aand E is shown in figure…. The shaft is machinedfrom plain carbon steel 30C8(Sut = 500 N/mm2) andthe expected reliability is 90%. When is the life ofthe shaft if notch sensitivity factor is 0.78?

3045

30

.

Ans. Refer question 1.46 in Unit 1.Q.3 A polished steel bar is subjected to axial tensileforce that varies from zero to Pmax It has groove 2mm deep and having a radius of 3 mm. Thetheoretical stress concentration factor and notchsensitivity factor at the groove are 1.8 and 0.95respectively. The outer diameter of the bar is 30mm. The ultimate tensile strength of the bar is 1250MPa. The endurance limit in reversed bending is600 MPa. Find the maximum force that the bar cancarry for 105 cycles with 90% reliability.Ans. Refer question 1.45 & 1.16 in Unit 1..



UNIT-2

Q.1 Differentiate between saddle key and sunk key.Ans. Refer Q. No. 2.19 in Unit 2.Q.2 Design a socket and spigot cotter joint to connecttwo steel rods of equal diameter. Each rod issubjected to an axial tensile force of 50 KN. Materialof two rods and cotter is steel 30C8 (Syt = 400 N/m2and Syc = 2Syt and Ssy = 0.5Syt) The factor of safety forrods, spigot end and socket end is assumed as 6while for cotter it is taken as 4.

Ans. Refer Q. No. 2.13 in Unit 2.Q.3 Design a rigid flange coupling transmitting 37.5 kWpower at 180 r.p.m. THe material for shafts andkeys is C 40 while that of flange is FG 200. AssumeSyc = 1.5 Syt and.Ans. Refer Q. No. 2.36 in Unit 2.

UNIT-3

Q.1 A single-clutch consists of one pair of contactingsurfaces. Because of space limitations, the outerdiameter of friction disk is fixed as D. Thepermissible intensity of pressure is P and coefficientof friction is . Assuming uniform wear theory,show that the torque transmiting capacity of theclutch is maximum when (d/D) is equal to 0.577.Ans. Refer similar Q. No.3.27 in Unit 3.Q.2 A transmission shaft supporting a spur gear B andthe pulley D. The shaft is mounted on two bearingsA and C. The diameter of the pulley an the pitchcircle diameters of the gear are 450 mm and 300mm respectively. The pulley transmits 20 KWpower at 500 rpm to gear P1 and P2 are belttensions in the tight and loose sides, while Pt and Prare tangential and radial components of gear toothforce. Assume, 0


.

Ans. Refer Q. No.3.21 in Unit 3.Q.3 A transmission shaft supporting a helical gear B andan over hauling bevel gear D as shown in figure…The shaft is mounted on two bearing A and C. THepitch circle diameter of the helical gear is 450 mmand the diameter of the bevel gear at the forces is450 mm. Power is transmitted from the helical gearto the bevel gear. The gears are keyed to the shaft.The material of the shaft is steel 45 C8

2 2600 / & 380 /ut ytN mm N mm .2.0 1.5 andb tK K Determine the shaft diameterusing the ASME code.




UNIT-4

Q.1 Part (a) is compulsory and attempt any two fromparts (b) , (c) and (d)(a) What are the basic types of threads used inpower screws?Ans. Refer Q. No. 4.20 in Unit 4..Q.2 A steel plate subjected to a force of 5 kN and fixed toa channel by means of three identical bolts is shownin figure . The bolts are made of plain carbon steel30C8 (Syt = 400 N/mm2) and the factor of safety is 3.Determine the diameter of the shank

.Ans. Refer question 4.11 in Unit 4.Q.3 A bracket for supporting the travelling crane isshown in figure. The bracket is fixed by means offour identical bolts, two at A and two at B. A load of5 kN is acting downwards at a distance of 250 mmfrom column. The bolts are made of steel 40C8 (Syt =380 N/mm2) and factor of safety is 5. Determine the

nominal diameter of the bolts on the basis ofmaximum principal stress Assume (dc= 0.8d):

:Ans. Refer question 4.8 in Unit 4.Q.4 A screw has single start square threads of 80 mmnominal diameter and 10 mm pitch. The screw isexerting a maximum axial force of 10 kN. The meanradius of friction coilar is 30 mm. The axial length ofthe nut is 40 mm. The coefficient of friction at thethreads and the collar is 0.12. The mean diameter ofthe rim of the handwheel is 500 mm. Calculate.(i) Force exerted at the rim to drive the screw(ii) The efficiency of the device,(iii) The bearing pressure on the threads in thenut.Ans. Refer question 4.35 in Unit 4.

UNIT-5

Q.1 What are the different types of joints used in rivetedjoints?.Ans. Refer Q. No.5.2 in Unit 5.Q.2 A boiler with 1.5 m inside diameter is subjected tointernal pressure of 1.5 MPa. It is made of steel bytriple rived double strap longitudinal butt joint withequal straps. The pitch of rivets in outer row istwice the inner row and patter is zig-zag. Theefficiency should be at least 80%. The permissiblestresses in tension, shear and compression are 80N/mm2, 60 N/mm2 and 120 N/mm2 respectively.Assume that rivets in double shear is 1.875 timesstronger than in single shear. Design the joint withneat sketch.Ans. Refer Q. No.5.14 in Unit 5.Q.3 An eccentrically loaded bracket is welded to thesupport as shown in figure The permissible shear

stress for the weld material is 55 N/mm2 and theload is static. Determine the throat and legdimensions for the welds.100 100150

25 kN


6 MACHINE DESIGN-I - Gate · PDF file6 MACHINE DESIGN-I SUBJECT CODE : 337551 ... Q.3 Design a cotter joint to carry a maximum load of ... The bolt is made of plain carbon steel 30C8

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