LP_III_I_MECH_55019(2012-2013)

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OEB.Tech-DMM-ID.BASWARAJ,DE

AN(FOE)

Jaya Prakash Narayan Educational Society Group of Institutions

Faculty of Engineering / Faculty of Pharmacy

Department: MECHANICAL ENGINEERING

COURSEPLAN

A. COURSE OVERVIEW

Year / Semester : III B TechI SEM Academic Year: 2012-13

Subject Title:

DESIGN OF MACHINE MEMBERS-I

Subject Code:

55019

Total Contact Hours: 63 Hours Duration of SEE: 03 Hours

Mid Term / Quiz. Marks: 25 Marks SEE Marks: 75 Marks

Objective 20 Minutes : 10 Marks Assignment 5 Marks

Subjective 90 Minutes: 10 Marks

Lesson Plan Author: D.Baswaraj. DEAN,FOE Sign Date : 10.05.2012

Checked By: M.Naveen Krishna Asst Prof MESign Date : 10.05.2012

CONTENTS:

Lesson PlanA. COURSE OVERVIEW.......................................................................................................1B. PREREQUISITES............................................................................................................1

C. COURSE CONTENT.........................................................................................................2

D. COURSE COVERAGE......................................................................................................2

E. MIDTERM EVALUATION..................................................................................................3

F. CHAPTER WISE PLANS....................................................................................................3

UNIT-

I......................................................................................................................................3UNIT-

II.....................................................................................................................................4

UNIT-III....................................................................................................................................5

UNIT-

IV....................................................................................................................................5

G. MID TERM I ...............................................................................................................6

H. MODEL QUESTIONS I..................................................................................................6

1.

OBJECTIVE.............................................................................................................................6

2.SUBJECTIVE...........................................................................................................................7

UNIT-

V......................................................................................................................................7

UNIT-

VI....................................................................................................................................8UNIT-

VII...................................................................................................................................9

UNIT-

VIII................................................................................................................................10

Page No.: 1/22Opposite Bhaghiratha Colony, JPN Nagar, Boothpur Road, MAHABUBNAGAR509001, AP (INDIA)

Phone: 91-8542-276111 / 33 / 44 / 55 Fax: 276122, Web:www.jpnes.org Email:[email protected]
http://www.jpnes.org/http://www.jpnes.org/http://www.jpnes.org/mailto:[email protected]:[email protected]:[email protected]:[email protected]://www.jpnes.org/

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B. PREREQUISITES

-This subject requires the student to know following topics / subject:

-Engineering Mechanics

-Engineering Drawing

-Kinematics of Machinery

-Material Science

-Strength of Materials

-Machine Drawing includes Assembly Drawing

Course Description:

i) Overview of the Course

-To know the stress in the machine members.

-To know the strength in the machine members when subjected to the External Loads.

-To know the strength of the Bolted,Riveted & welded joints which are used for making the boiler shells andother cylindrical components.

-To Find the dimensions of the Keys,Cutters & Shafts which are used for Power Transmission.

-To know the strength of the Knuckle joint which are used for shafts during transmission of the power.

To know the strength of the Springs which are used to withstand the shocks during the transmission of the

power.

ii) Relevance of the Course

- Design of Mechanical Components

-Manufacturing of the Components

-Design of the Shafts

-Design of Various joints like bolted ,riveted ,welded & Knuckle joints

-Design of Mechanical Springs

i i i ) Ap plication s areas

- Design of Mechanical Components

-Manufacturing of the Components

-Design of the Shafts

-Design of Various joints like bolted ,riveted ,welded & Knuckle joints

-Design of Mechanical springs.iv) Overall Experiences



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C. COURSE CONTENTCourse Code: 55019 L-T-P: 4+1*/-/5

Course Title: DESIGN OF MACHINEMEMBERS-I

Midterm Exam Hours: 60 Minutes20 Minutes

Teaching Hours: 60 Hrs End Semester Exam Hours: 3 Hours

D. COURSE COVERAGE

Cours e Coverage / Unit izat ion for Midterm / Quiz Exams and Semester End Exams

Unit ChapterTeaching

hours

No of question in

MidTerm-1

Quiz-1

MidTerm-2

Quiz-2

MidTerm-3

Quiz-3

Assignment

EndSem

I 1 INTRODUCTION ANDSTRESSES IN MACHINEMEMBERS

11 01 05 - - - - 03 01

II 1 STRENGTH OF MACHINEMEMBERS

07 01 05 - - - - 03 01

III 1 RIVETED JOINTS 05 01(a) 03 - - - - 0201

2 WELDED JOINTS 05 01(b) 02 - - - - 02

IV 1 BOLTED JOINTS 07 01 05 - - - - 03 01

V 1 AXIALLY LOADED JOINTS 06 - - 01 05 - - 03 01

VI 1 DESIGN OF SHAFTS 07 - - 01 05 - - 03 01

VII 1 SHAFT COUPLING : 05 - - 01 05 - - 03 01

VIII 1 MECHANICAL SPRINGS 07 - - 01 05 - - 03 01

TOTAL 60 04 20 04 20 - - 26 08

Instructions:

Subjective test : 10 marks. Answer 3 out of 5 questions in 60 minutes.

Objective test : 10 marks. Answer all 20 questions in 20 minutes.

Assignment : 5 marks. One assignment per chapter.

Semester End Exam: 75 marks. Answer 5 out of 8 questions in 3 hours. Each Question carries 20

marks and may consist of sub-questions.

Mixing of sub-questions from different chapters within a unit (only for Unit I and Unit II) is allowed

in SEE.

Date: Dean / Head of Department

E. MIDTERM EVALUATION

Midterm / Quiz Evaluation Scheme

Evaluation Scheme Assessment Weightage in Marks

Midterm Exam1 I Yr to IV Yr 20

Midterm Exam - 2 I Yr to IV Yr 20

Midterm Exam3 * Only I year 20

Assignments One assignment per Chapter 05

Classroom activity Some Weightage

Other Activities Some Weightage

Total I Year Avg of best 2 of 3 Tests

II to IV year Best of 2 Tests



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F. CHAPTER WISE PLANS

UNIT-I

Chapterwiseplan

Chapter Number : 01 Approximate Time needed: 09 Hrs

Title: INTRODUCTION AND STRESSES IN MACHINE MEMBERS

Learning objectives:

The student should be able to:

1.-The properties of engineering materials and selection materials for design of the components.2.-The consideration of the manufacturing methods and allowances during manufacturing of the component3.-The limits, fits and tolerances during assembling of the parts of a components.4.-Simple stresses, impact stresses and stiffness of the members during the design

Lesson Schedule:

ClassNo.

Portion Covered / Hour (Estimate) DatePlanned

DateEngaged

Remarks

1 Introduction to Subject 02.07.2012

2 introduction to Subject 04.07.2012

3 General considerations in the design of EngineeringMaterials

07.07.2012

4 Materials propertiesselection 09.07.2012

5 Manufacturing consideration in design. 11.07.2012

6 Tolerances and fitsBIS codes of steels 14.07.2012

7 Simple stressesComplex stressesimpact stressesstress strain relation

16.07.2012

8 Various theories of failurefactor of safety 18.07.2012

9 Design for strength and rigidity 21.07.2012

10 Preferred numbers 23.07.2012

11 The concept of stiffness in tension, bending, torsion and

combined situations

23.07.2012

Application Areas:

-Manufacturing industries

- Assembly sections

- In design of sections of design department

Home work for th e day: Date

1 What are the factors to be considered for the selection of materials for the design ofmachine elements

2 Enumerate the most commonly used engineering materials and state at least oneimportant property and one application of each

3 Enumerate various manufacturing methods of a machine parts which a designer shouldknow.

4 Define the terms:i. Stress area ii. Pitch iii. Major diameter related to screw fastenings:

5 Difference between nominal size and basic size.

6 What are the fits and tolerances? How they are designated?

7 Explain the need in computing endurance limit of given component.

8 Explain preferred numbers in engineering design.

9 Explain the various factors to be considered for factor of safety in machine design.

10 Explain Indian Standard systems of limits and ts.

Experiences:



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UNIT-II

Chapterwiseplan


Title: FATIGUE LOADING



1.- Stress concentration factor - Fatigue stress concentration factor - Notch sensitivity2.- Design for fluctuating stresses - Endurance limits and its estimation - Fatigue theories of failure

Lesson Schedule:

ClassNo.


DateEngaged

Remarks

1 Stress concentrationTheoretical stress Concentrationfactor

25.07.2012

2 Fatigue stress concentration factor notch sensitivity 25.07.2012

3 Design for fluctuating stresses 28.07.2012

4 Endurance limitEstimation of Endurance strength 30.07.2012

5 Fatigue theories of failure - Goodmansline 30.07.20126 Soderbergsline 01.08.2012

7 Modified goodmansline 01.08.2012

Application Areas:

- Design of the component repeated and reversal loads like shafts and axles etc.

- Design of the component for fatigue loading


1 Define factor of safety under static and fluctuating loads.

2 A steel connecting rod is subjected to a completely reversed axial load of 16 KN. Suggest the

suitable diameter of the rod using a factor of safety 2. The ultimate tensile strength of thematerial is 11000 N/mm2, and yield strength 9300 N/mm2. Neglect column friction and the

effect of stress concentration.

3 Find the diameter of a shaft made of Manganese steel having the ultimate tensile strength as 6

N/mm2 and yield stress as 4.4 N/mm2. The shaft is subjected to completely reversed axial load

of 100 KN. Neglect stress concentration factor and assume surface finish factor as 0.8 andsize factor as 0.85.

4 A bolt is subjected to a direct tensile load of 18000 N and a shear load of 12000N. The yieldstress of the bolt material in simple tension is 350 MPa. Use a factor of safety of 3 andpoisonsratio of 0.25. Calculate the diameter of the bolt by:i) Maximum shear stress theory and ii) Maximum principal strain theory.

5 Explain the following methods of reducing stress concentrationi) Drilled holes ii) Using large fillet radius iii) Added grooves

6 A shaft is made of steel ultimate tensile strength 700 MPa and yield point 420 MPa issubjected to a torque varying from 200N m anti-clockwise to 600 N m clockwise. Calculate thediameter of the shaft if the factor of safety is 2 and it is based on the yield point and theendurance strength in shear.

7 A pulley is keyed to a shaft midway between two anti- friction bearings. The bending momenat the pulley varies from 250 KN-mm to 750 KN-mm and the torsional moment in the shafvaries from 100 KN-mm to 300 KN-mm. The frequency of the variation of the load is same athe shaft speed. The shaft is made of a cold drawn steel having an ultimate strength of 550 N

mm2 and yield strength of 450 N/mm2. Determine the required diameter for an infinite life. Thestress concentration factor for the key way in bending and torsion may be taken as 1.8 and 1.5respectively. The factor of safety is 2.0. Take size factor =0.85 and surface finish factor=0.88.

Experiences:



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UNIT-III

Chapterwiseplan


Title: RIVETED JOINTS



1.- Modes of failure of riveted joints2.- Efficiency of riveted joints3.- Design of boiler joints4.- Eccentrically loaded riveted joints5.- Design of Eccentrically loaded riveted joints

Lesson Schedule:

ClassNo.


DateEngaged

Remarks

1 Modes of failure of riveted joints 04.08.2012

2 Strength Equations 06.08.2012

3 Efficiency of riveted joints 06.08.2012

4 Design of boiler joints 08.08.2012

5 Eccentrically loaded riveted joints. 08.08.2012

Application Areas:

- Design of the boiler joints

- Design of the boiler joints subjected to eccentrically loaded


1 A double riveted lap joint is made between 20 mm thick plates. The rivet diameter and

pitch are 30 mm and 80 mm respectively. If the ultimate stresses are 450 N/mm 2 in

tension and 350 N/mm2 in shear and 540 N/mm2 in crushing and the minimum force

per meter, which will rupture the joint. If the above joint is subjected to a load such thathe factor of safety is 3, find out the actual stresses developed in the plates and the

2 Write the procedure for designing a lozenge joint.

3 Two lengths of mild steel tie rod having width 300 mm are to be connected by means oLozenge joint with two cover plates to withstand a tensile load of 200 KN. Completelydesign the joint, if the permissible stresses are 100 N/mm2 in tension, 70 N/mm2 inshear and 160 N/mm2 in crushing. Draw a neat sketch of the joint.

4 What is the difference between caulking and fullering? Explain with the help of neatsketches.

5 Explain the procedure for designing a longitudinal and circumferential joint for a boiler

Experiences:

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UNIT-III

Chapterwiseplan


Title: WELDED JOINTS



1.- Design of the fillet weld2.- Design of the circular fillet weld subjected to bending and torsion3.- Design of welded joints when subjected to eccentric loads4.-Types of Welded joints are posiible.

Lesson Schedule:

ClassNo.


DateEngaged

Remarks

1 Design of Fillet welds 11.08.2012

2 Design of the welded joints subjected to axial loads 11.08.2012

3 Circular fillet welds 13.08.2012

4 Design of the welded joints subjected to bending andtorsion13.08.2012

5 Eccentrically loaded joints. 18.08.2012

Application Areas:

- Welding joints is extensively used in fabrication as an alternative to casting or forging and as a replacement

for bolted and riveted joints

- Is also used in as a repairing medium

-To make gates Shutters etc.

Home work for th e day Date

1 What do you understand by the term welded joint? How it differs from riveted joint?

2 What are the assumptions made in the design of welded joints

3 Explain the procedure for designing axially loaded unsymmetrical welded section.

4 Determine the length of the weld run for a plate size 120 mm wide and 15 mm thick to bewelded to another plate by means ofi. A single transverse weld andii. Double parallel fillet welds when the joint is subjected to variable loads.

5 Develop an expression for the maximum shear stress induced in all aroundcircular llet weld subjected to Torsion.

6 A plate 100 mm wide and 10 mm thick is to be welded with another plate by means oftransverse welds at the ends. If the plates are subjected to a load of 70 kN, nd the size of weldfor static as well as fatigue load. The permissible tensile stress should not exceed 70 N/mm2.

Experiences:

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UNIT-IV

Chapterwiseplan


Title: BOLTED JOINTS



1.- Design of the bolts with Pre-stresses like stress due to tightening of nut etc.2.- Design of the bolted joints under eccentric load3.- Make a bolt with uniform strength4.- To prepare cylindrical cover joints

Lesson Schedule:

ClassNo.


DateEngaged

Remarks

1 Design of bolts with Pre Stresses 22.08.2012

2 Problems on design of bolts with Pre Stresses 22.08.2012

3 Design of joints under eccentric loading 25.08.2012

4 Problems on design of joints under eccentric loading 25.08.20125 Problems on design of joints under eccentric loading 27.08.2012

6 Bolt of uniform strength 27.08.2012

7 Cylinder cover socket 29.08.2012

Application Areas:

- Where temporary joints are required

- Foundations of the heavy equipments

- Lifting of heavy equipments

- Design of boiler cover plate

Home work for th e day

Date

1 The base of a pillar crane is fastened to the foundation by 12 bolts spaced equally on a boltcircle of diameter 2 m. The diameter of the pillar base is 2.5 m. Determine the size of boltswhen the crane carries a load of 150 KN at a distance of 6 m from the center of the base. The

allowable stress for the bolt material is 170 N/mm2.

2 Derive an expression for the maximum load in a bolt when a bracket with circular base isbolted to a wall by means of six bolts.

3 Discuss the significance of initial tightening load and the applied load so far as bolts areconcerned. Explain which of the above loads must be greater for a property designed bolted

joint and show how each affects the total load on the bolts.

4 Discuss of bolts of uniform strength giving examples of practical applications of such bolts.

5 A punching press is required to punch a maximum hole size of 30 mm diameter in a material

having ultimate shear strength of 350 N/mm2. If the thickness of the sheet is 6 mm, design the

screw and the nut.

6 An eye bolt is to be used for lifting a load of 100 KN. Find the nominal diameter of the bolt, if

the tensile stress is not to exceed 130 N/mm2.

7 Define the termsi. pitch ii. Nominal diameter iii. Root diameter corresponding to bolted joints.

8 A Flanged bearing is fastened to a frame by means of 6 bolts spaced equally on 550 mm bolcircle. The diameter of bearing flange is 750mm and a load of 200 KN acts at a distance 350

mm from the frame. Determine the size of the bolts, assuming tensile stress as 120 N/mm2 fothe bolts.

Experiences:

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G. MID TERM I

H. MODEL QUESTIONSI

1. OBJECTIVE

Midterm Exam No.: 01 Semester / Year: 03/01

Subject Design of Machine Members-I Subject Code: 55019

Instructions: All question are compulsory and equal marks

1

Steels containing up to 0.15% of carbon is known as

A)Mild Steel B)Dead mild steel C)Medium Carbon steel D)High carbon steel

2

According to Indian Standard specifications ,100 H6/g5 means that the

A)Actual size is 100 B)Basic size is 100 C)Diff between actualsize and basic size is 100

D)None of above.

3

An aluminum member is designed based on

A)yield stress B)elastic limit stress C)proof stress D)Ultimate Stress

4

The strain energy stored in a body ,when suddenly loaded,is the strain energy stored when sameload is applied gradually

A)Equal to B)One-Half C)Twice D)Four times

5

Failure of a material is called Fatigue when it falls

A)at the elastic limit B)below elastic limit C)at the yield point D) above yield point

6

The ratio of endurance limit in shear to the endurance limit in bending is

A)0.25 B)0.35 C)0.50 D)0.70

7

The rivet head used for boiler plate riveting is usually

A)Snap Head

B)Pan Head

C)Counter shank head

D)Conical Head

8

The longitudinal joint in boilers is used to get the required

A) Length of the boiler B)Diameter of the Boiler C)Length & diameter ofthe boiler

D)Efficiency of the boiler

9

The parallel fillet welded joint is designed for

A)Tensile strength B) Comp Strength C)Bending Strength D)Shear Strength

10

A screw is specified byits

A) Major diameter B)Minor diameter C)Pitch diameter D)Pitch

11 18/8 Steels contains % of chromium and % of nickel.

12 A steel with 0.8 percentage of carbon is known as steel.

13 The surface finish factor for a mirror polished material is

14 In cyclic loading, stress concentration is more serious in materials.

15 A lap joint is always in shear.

16 The center to center distance between two consecutive rivets in a row is called

17 The electric arc welding is a type of welding

18 The size of the weld in butt welded joint equal to times of throat weld.

19 When nut is tightened by placing the washer below it,the bolt will subjected to stress

20 The eye bolts are used for applications.



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2. SUBJECTIVE

ModelQuestionPaperforMidterm ExamSubjective



Instructions: Answer any three questions. All questions carry equal marks.

1 a Explain the various factors to be considered for factor of safety in machine design.

b Explain Indian Standard systems of limits and fits.

c Enumerate various manufacturing methods of a machine parts which a designer should know.

d Define the terms:i. Stress area ii. Pitch iii. Major diameter related to screw fastenings:

2 a Explain the effect of the following factors on the type of fatigue failure.i. Stress distribution ,ii. ii. Manner of loadingiii. iii. Strain rate

b Find the diameter of a shaft made of Manganese steel having the ultimate tensile strength as 6 N/mm2

and yield stress as 4.4 N/mm2. The shaft is subjected to completely reversed axial load of 100 KN.

Neglect stress concentration factor and assume surface finish factor as 0.8 and size factor as 0.85.

c Explain the following methods of reducing stress concentrationi) Drilled holes ii) Using large fillet radius iii) Added grooves

3 a Two lengths of mild steel tie rod having width 300 mm are to be connected by means of Lozenge joint

with two cover plates to withstand a tensile load of 200 KN. Completely design the joint, if the

permissible stresses are 100 N/mm2 in tension, 70 N/mm2 in shear and 160 N/mm2 in crushing. Draa neat sketch of the joint.

b What is the difference between caulking and fullering? Explain with the help of neat sketches.

c Develop an expression for the maximum shear stress induced in all around circular fillet weld subjectedto Torsion.

d A plate 100 mm wide and 10 mm thick is to be welded with another plate by means of transverse weldsat the ends. If the plates are subjected to a load of 70 KN, nd the size of weld for static as well as

fatigue load. The permissible tensile stress should not exceed 70 N/mm2.

4 a Derive an expression for the maximum load in a bolt when a bracket withcircular base is bolted to a wall by means of six bolts.

b Discuss the significance of initial tightening load and the applied load so far as bolts are concerned.Explain which of the above loads must be greater for a property designed bolted joint and show howeach affects the total load on the bolts.

c Discuss of bolts of uniform strength giving examples of practical applications of such bolts.

d A punching press is required to punch a maximum hole size of 30 mm diameter in a material having

ultimate shear strength of 350 N/mm2. If the thickness of the sheet is 6 mm, design the screw and the

nut.

e An eye bolt is to be used for lifting a load of 100 KN. Find the nominal diameter of the bolt, if the tensilestress is not to exceed 130 N/mm 2.



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UNIT-V

Chapterwiseplan


Title: AXIALLY LOADED JOINTS:



1.-Types Keys and design of key.2.-Cotter and Design of cotter joints.3.-Design of sleeve and cotter joints4.-Design of Knuckle joint

Lesson Schedule:

ClassNo.


DateEngaged

Remarks

1 Design of Keysstresses in keys & Problems 01.09.2012

2 Design of cottered joints & Problems 10.09.2012

3 Design of spigot and socket & Problems 10.09.2012

4 Design of sleeve and cotter & Problems 12.09.20125 Design of jib and cotter joints & Problems 12.09.2012

6 Design of Knuckle joints & Problems 15.09.2012

Application Areas:

-Used in connection a piston rod to the cross head of a reciprocating steam engine,

-A piston rod and its extension as a tail or pump rod, strap end of connecting rod.

- In Link of a cycle chain , tie rod for ruff truss,valve rod joint with eccentric rod

-Tension link in bridge structure.


1 Design and draw a cotter joint to support a load varying from 3 KN in compression to 4 KN intension. The material used is carbon steel for which the following allowable stresses may be

used. The load is applied statistically. Tensile stress & compressive stress = 500 N/mm2,

shear stress = 350 N/mm2 and crushing stress = 900 N/mm2.

2 Design and draw a sleeve and cotter joint to connect two rods to transmitmaximum tensile load of 100 KN. Assume sleeve, cotter and rods are made of

same material and design stresses in the material are 75 N/mm2 in tension,

150 in crushing and 45 N/mm2 in shear.

3 What is a knuckle joint? where it is used?

4 Design a knuckle joint to transmit 140 KN force, with permissible stresses

in tension, shear and compression are 75 N/mm2, 60 N/mm2 150 N/mm2

respectively.5 Design a Knuckle joint for a tie rod of a circular section to sustain maximum pull of 60KN. The

ultimate strength of the material of the rod against tearing is 400 . The ultimate tensile andshearing strength of the pin material are 490 and 380 respectively. The factor of safety is 3.Sketch the designed join with dimensions.

6 A)Explain the design procedure of sunk keys

B)Prove that a square key is equally strong in shear and crushing.

(C)Design a cotter joint to support a load of 35KN which is subjected to a slow reversal o

direction. The permissible stresses are 80 is tension, 68 N/mm 2 in shear and 160 N/mm2

in crushing.

Experiences:

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UNIT-VI

Chapterwiseplan


Title: DESIGN OF SHAFTS



1.-Shaft Materials,Material Selection process for shafts2.-Types of shafts3.-Design procedure of Solid and Hallow shafts4.-Design procedure of Solid and Hallow shafts when subjected to both bending and axial loads5.-Design of gear and belt drives

Lesson Schedule:

ClassNo.


DateEngaged

Remarks

1 Design of solid shafts for strength and rigidity 17.09.2012

2 Design of hollow shafts for strength and rigidity 17.09.2012

3 Design of shafts for bending loads 22.09.2012

4 Design of shafts for axial loads 24.09.2012

5 Design of shafts for combined bending and axial loads 24.09.2012

6 Shaft sizesBIS code. 26.09.2012

7 Design of shaft for a gear and belt drives. 26.09.2012

Application Areas:

-For transmission of motion from one place to other place through couplings.

-Power transmission Belt drives , chain drives and rope drives.


1

A shaft is supported by two bearings placed 1m apart. A 600 mm diameter pulley is

mounted at a distance of 300 mm to the right of left hand bearing and this drives a pulleydirectly below it with the help of belt having maximum tension of 2.25 KN. Another pulley400 mm diameter is placed 200 mm to the left of right hand bearing and is driven withthe help of electric motor and belt, which is placed horizontally to the right. The angle ofcontact for both the pulleys is 1800 and = 0.24. Determine the suitable diameter for asolid shaft, allowing working stress of 63 N/mm2 in tension and 42 N/mm2 in shear forthe material of the shaft. Assume that the torque on one pulley is equal to that on theother pulley.

2 Differentiate between torsional rigidity design and lateral rigidity design of shafts.

3

A shaft receives 20 kW power at 240 R.P.M through a 500 mm belt pulley, mountedcentrally between two bearings, 600 mm apart and transmits it through a 250 mm gear,overhanging the right bearing by 250 mm. The belt drive is horizontal, and the gea

drives, with a downward tangential force. The ratio of belt tension is 2.5. Determine theshaft diameter, assuming permissible normal stress as 80 N/mm2

4

A machine shaft supported on bearings having their centers 750mm apart, transmits 185kW at 700 R.P.M. A gear of 200 mm and 200 pressure angle is located 250mm to theright of the left hand bearing and a 450 mm diameter pulley is mounted at 200 mm to theright of left hand bearing. The gear is driven by a pinion with a downward tangentialforce, while the pulley drives a horizontal belt having 1800 angle of contact. The pulleweighs 1 KN and tension ratio is 3. Find the diameter of the shaft, if the allowable shea

stress of the material is 65 N/mm2

5 What is the difference between a shaft and an axle? How the shafts are classified?

6 Determine the diameter of the hollow shaft having inside diameter 0.5 times the outside

diameter. The permissible shear stress is limited to 250 N/mm2.The shaft carries a 800mm diameter cast iron pulley. This pulley is driven by another pulley mounted on the

shaft placed below it. The belt ends are parallel and vertical. The ratio of tensions in thebelt is 3. The pulley on the hollow shaft weighs 900 N and overhangs the nearest



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bearing by 250 mm. The pulley is to transmit 35 KW power at 500 rpm.

7

A hollow shaft carries an 80cm diameter pulley witch is driven by another pulley mountedon a shaft placed below it through belt drive. The belt ends are parallel and vertical. Theratio of tensions in the belt is 3 and 35KW power is transmitted at 400rpm. The pulleyweighs 800N and overhangs the nearest bearing by 20 cm. Calculate the diameter of thehollow shaft when the ratio of inside diameter to outside diameter is 0.5 and permissibleshear stress for the shaft material is limited to 180.

8

In axial flow rotary compressor, the shaft is subjected to a maximum twisting moment of1200 N-m and a maximum bending moment of 2500 N-m. Neglecting the axial load onthe shaft, determine the diameter of the shaft, if the allowable shear stress is 45.

Assume = 1.5 and = 1.2. If the shaft is to be hollow one with = 4, what will be thematerial saving in the hollow shaft 2/N mm

9

An automobile transmission shaft is required to transmit 30KW at 400rpm. The outsidediameter must not exceed 45mm and the maximum shear stress is not to exceed95MPa. Compare the weights of solid and hollow shafts which would meet theserequirements. Also compare the stiffnesses.

Experiences:

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UNIT-VII

Chapterwiseplan


Title: SHAFT COUPLING



1.-Function of couplings,types of couplings2.-Design procedure of Muff,Split & Flange coupling3.-Design procedure of Pin & Bush coupling

Lesson Schedule:

ClassNo.


DateEngaged

Remarks

1 Types Rigid couplingsDesign of Muff Coupling, 01.10.2012

2 Design of Split muff 01.10.2012

3 Design of Flange couplings. 03.10.2012

4 Types Flexible couplings & Design of pin coupling 03.10.2012

5 Design of bush coupling 06.10.2012

6 Problems on above topics 08.10.2012

Application Areas:

- For transmitting power from one shaft to another shaft .

- For connecting counter shaft of turbine to electrical generator.


1 Design a cast iron protective type flange coupling to transmit 16 KW at 900 rpm from anelectric motor to a compressor. The service factor may be assumed as 1.5.The following

permissible stresses may be used: Shear stress for shaft, bolt and key material is 60 N/mm 2

Crushing stress for bolt and key is 70 N/mm 2, Shear stress for cast iron is 10 N/mm2. Draw a

neat sketch of the coupling.2 Design a bushed-pin type flexible coupling for connecting the shafts of an electric motor, and

centrifugal pump. The shaft diameters are 50 and 40 mm respectively. The power to betransmitted is 75 KW at 850 rpm. Take the bearing pressure on the rubber bush as 0.75

N/mm2, normal stress for pins as 65 N/mm2, shear and crushing stresses for the key as 55 N/

mm2 and 95 N/mm2 respectively.

3 Design a clamp coupling for a shaft diameter of 60 mm. The torsional momentto be transmitted by this coupling taking in to account over loading as 160 N-m. The number o

bolts used are 6 and the allowable stress in the material of the bolt is limited to 75 N/mm 2. The

coefficient of friction between the shaft and muff material is 0.25.Draw sectional elevation othe designed clamp coupling.

4 Give the classification of couplings.

5 Design and draw a muff coupling to transmit 90 KW power at 108 rpm. The shaft and key aremade of the same material having allowable shear stress of 63 N/mm2 and compressive

stress of 100 N/mm2 The flange is made of cast iron with allowable shear stress as 35 N/mm2.

6 Design a bushed pin flexible coupling for connecting a motor shaft to a pump shaft for thefollowing service conditions. Power to be transmitted = 15KW ,Speed of the motor shaft =1440 rpm ,Diameter of the motor shaft = 60 mm ,Diameter of the pump shaft = 50 mm ,Bearing pressure on the rubber bush = 0.5 N/mm2 Allowable stress in the pins = 18 N/mm2

7 Design a compression coupling for a shaft to transmit 1200 N-m. The allowable shear stressfor shaft and key is 35 MPa and the number of bolts connecting the two halves are 4. Thepermissible tensile stress for the bolt material is 65 MPa. The Coefficient of friction betweenthe muff and the shaft surface may be taken as 0.3. Draw a neat sketch of the coupling.

Experiences:

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UNIT-VIII

Chapterwiseplan


Title: MECHANICAL SPRINGS



1.-Function of Springs,Types of Springs2.-Stresses and deflections of Helical Springs3.-Natural Frequency and Energy Storage of Helical Springs4.-Co-Axial Springs

Lesson Schedule:

ClassNo.


DateEngaged

Remarks

1 Stresses and deflections of helical springs 10.10.2012

2 Stresses and deflections of Extension & compressionsprings

10.10.2012

3 Springs for fatigue loading 13.10.2012

4 Natural frequency of helical springs 15.10.2012

5 Energy storage capacity of Helical Springs 15.10.2012

6 Stresses and deflections of helical torsion springs 17.10.2012

7 Design of Co-axial springs 29.10.2012

8 Problems on above topics 31.10.2012

Application Areas:

-For Store Energy as in Watches ,Toys etc

-For measure forces ,as in Spring balance and engine indicators

-For control motion by maintaining contact between two elements as in cams and followers

-For apply forces as in brakes,clutches and spring -loaded valves.

-For cushion,absorb and control energy due to shock and vibration as in car springs,railway buffers ,air craft

landing gears ,shock absorbers and vibration dampers.

Home work fo r the day: Date

1 Under what circumstances concentric springs are preferred?

2 A load of 2 KN is dropped axially on a close coiled helical compression spring from a height of260 mm. The spring has 16 active coils. Take wire diameter as 20 mm, spring index as 8.

Determine the deflection and stress induced in the spring. Take G= 0.84 105 N/mm2..

3 Differentiate between a helical torsion spring and a spiral spring.

4 A close coiled helical compression springs of 12 active coils has a spring stiffness of P0. It iscut in to two springs having 5 and 7 turns. Determine spring stiffnesses of resulting springs.

5 List out functions of springs with suitable examples.

6 A helical spring is to support a load of 2 KN. The spring is guided by a rod of 55 mm diameter.The spring undergoes a deflection of 42 mm under the load. Determine the diameter of thewire and the number of turns required. Use C-60 steel with a factor of safety of 2.5. Assumesuitable necessary data:

7 Explain what do you understand by A.M. Wahls factor and state its importance in the design ofhelical springs.

A helical coil spring is to be subjected to loads ranging from 350 to 425 N. The axialcompression of the spring over the above load range is approximately 8 mm. Assuming aspring index of approximately 5, determine i. The size of wire ii. The outside diameter of thespring and iii. The number of active coils. Assume necessary data.

Experiences:



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MID TERMIIH. MODEL QUESTIONSII

1. OBJECTVE



Instructions: All question are compulsory and equal marks

1

Which of the following cotter joint is used to connect strap end of a connecting rod ?

A) socket and spigot joint B) Sleeve and cotter joint C)Gib and cotterjoint

D) None of the above

2

In a steam engine, the valve rod is connected to an eccentric by means of a

A) knuckle joint B)Universal joint C) Flange coupling D) Cotter joint

3

The type of stresses developed in the key is/are

A) Shear stress alone B)Bearing stress alone C) Both shear and bearingstresses

D)Shearing, bearing andbending stresses

4For a square key made of mild steel, the shear and crushing strengths are related as

A)shear strength =crushing strength

B) shear strength > crushingstrength

C) shear strength < crushingstrength

D)None of the above

5

Oldham's coupling is used to connect two shafts

A) which are perfectlyaligned

B) Which are not in exactalignment

C) Which have lateralmisalignment

D) Whose axes intersect at asmall angle

6

Two shafts will have equal strength, if

A)diameter of both theshafts is same

B) Angle of twist of both theshafts is same

C)material of both the shaftsis same

D) All of the above

7

When a shaft is subjected to a bending moment M and a twisting moment T, then the equivalent twisting moment iequal to

A) M+T B)M2+T2 C)M2+T2 D) M2-T2

8

The design of shafts made of brittle materials is based on

A) Guest's theory B) Rankine's theory C)St. Venant's theory D) Von Mises Theory

9

In a closed coiled helical spring, the spring index is given by D/d where D and d are the mean coil diameter and wirdiameter respectively. For considering the effect of curvature, the Wahl's stress factor K is given by

A) 4C-1/(4C+4) +0.615/C B) 4C-1/(4C-4) + 0.615/C C) 4C+1/(4C-4)0.615/C D) 4C+1/(4C+4)0.615/C

10

When helical compression spring is cut into halves, the stiffness of the resulting spring will be

A) same B)Double C)one-half D)One-fourth

11 In a gib and cotter joint, the thickness of gib is ------- thickness of cotter. (More than/ Less than /Equal to)

12 In a turn buckle, if one of the rods has left hands threads, then the other rod will have hand threads.

13 when a pulley or other mating piece is required to slide along the shaft, a type of sunk key is used.

14 The sleeve of muff coupling is designed as a Shaft

15 The standard length of the shaft is meters.

16 The maximum normal stress theory is used for materials.

17 A spring used to absorb shocks and vibrations is

18 The spring mostly used in gramophones is

19When a helical compression spring is subjected to an axial compressive load, the stress induced in the

wire is

20When two concentric coil springs made of the same material, having same length and compressed equally by aaxial load, the shared by the two springs will be to the square of the diameters of the wires of the twsprings.



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2. SUBJECTIVE

ModelQuestionPaperforMidterm ExamSubjective



Instructions: Answer any three questions. All questions carry equal marks.

1 (A) Describe various types of keys.

(B) Design a knuckle joint to transmit 140 KN force, with permissible stresses in tension, shearand compression are 75 N/mm2, 60 N/mm2 150 N/mm2 respectively.

2 (A) What is the difference between a shaft and an axle? How the shafts are classified?

(B) Determine the diameter of the hollow shaft having inside diameter 0.5 times the outsidediameter. The permissible shear stress is limited to 250 N/mm2.The shaft carries a 800 mmdiameter cast iron pulley. This pulley is driven by another pulley mounted on the shaft placedbelow it. The belt ends are parallel and vertical. The ratio of tensions in the belt is 3. The pulleon the hollow shaft weighs 900 N and overhangs the nearest bearing by 250 mm. The pulley isto transmit 35 KW power at 500 rpm.

3

(A)Give the classification of couplings.(B)Design a cast iron protective type flange coupling to transmit 16 KW at 900 rpm from anelectric motor to a compressor. The service factor may be assumed as 1.5.The followingpermissible stresses may be used: Shear stress for shaft, bolt and key material is 60 N/mm2Crushing stress for bolt and key is 70 N/mm2, Shear stress for cast iron is 10 N/mm 2. Draw aneat sketch of the coupling.

4 (A)List out functions of springs with suitable examples.

(B)A helical coil spring is to be subjected to loads ranging from 350 to 425 N. The axialcompression of the spring over the above load range is approximately 8 mm. Assuming a springindex of approximately 5, determine i. The size of wire ,ii. The outside diameter of the springand iii. The number of active coils.

Assume necessary data.



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I. PREPARATION

1. MODEL QUESTION PAPER

ModelQuestionPaperforSemester EndExam

Subject: DMM-I Subject Code: 55019

Instructions: Answer any five questions. All questions carry equal marks.

1 (A) List-out the different types of stresses, to which a screwed fastener is generally subjected.(B) The head of a steam engine cylinder of 600 mm diameter is subjected to steam pressure of1.3N/mm2. The head is held in place by 16 bolts of M36 size. A soft copper gasket is used to make the

joint steam tight. Determine the stress induced in the bolts. [6+10]

2 (A)Explain the need in computing endurance limit of given component.(B) A pulley is keyed to a shaft midway between two anti- friction bearings. The bending moment at thepulley varies from 250 KN-mm to 750 KN-mm and the torsional moment in the shaft varies from 100 KN-mm to 300 KN-mm. The frequency of the variation of the load is same as the shaft speed. The shaft is

made of a cold drawn steel having an ultimate strength of 550 N/mm 2. and yield strength of 450 N/mm2..Determine the required diameter for an infinite life. The stress concentration factor for the key way in

bending and torsion may be taken as 1.8 and 1.5 respectively. The factor of safety is 2.0. Take sizefactor =0.85 and surface finish factor=0.88.

3

A bracket is riveted to a column by 6 rivets (A,B,C,D,E and F) of equal size as shown in Figure \ref {figThe centers of rivets A,B,C are on the same vertical line and the centers of D,E , F are on the anothervertical line. The centers of A, F are on the same horizontal line. The centers of B, E are on onehorizontal line and the centers of C, D are on another horizontal line. The vertical distance between A, Band B, C are 75 mm and 75 mm respectively. The horizontal distance between C, D is 100 mm. Icarries a load of 60 kN at a horizontal distance of 200 mm from the center of the column. If themaximum shear stress in the rivet is limited to 150 MPa, find the diameter of the rivet.

4 A) Define the termsi. pitch ii. Nominal diameter iii. Root diameter corresponding to bolted joints.(B) A flanged bearing is fastened to a frame by means of 6 bolts spaced equally on 550 mm bolt circle.The diameter of bearing flange is 750mm and a load of 200 KN acts at a distance 350 mm from theframe. Determine the size of the bolts, assuming tensile stress as 120 N/mm2 for the bolts.[6+10]

5 (A) Which material is generally used for a cotter? Why the taper is given on a cotter?(B) Two rod ends are to be joined by means of a cotter joint, by using a sleeve and two cotters. The jointis subjected to an axial load of 120 KN, which alternately changes slowly from tension to compression.The permissible stresses for the rods, sleeve and cotter material are 100 N/mm2 in tension, 80 N/mm2in shear, and 150 N/mm2 in compression.[6+10]

6 (A) Deduce design equation for a hollow shaft subjected to bending moment M, torque T and axial thrustFa.

(b) Determine the diameters of a hollow shaft, transmitting a torque of 450 N-m, and subjected to abending moment of 600 N-m. Assume the shock and fatigue factors in torsion and bending as 1.2 and1.3 respectively. The ratio of outer to inner radii is 1.5. Find the diameter, if the shaft is a solid one.Compare the weights of hollow and solid shafts.[6+10]

7 Design a cast iron protective type flange coupling to transmit 16 kW at 900 rpm from an electric motor toa compressor. The service factor may be assumed as 1.5. The following permissible stresses may beused: Shear stress for shaft, bolt and key material is 60 N/mm2, Crushing stress for bolt and key is 70N/mm2, Shear stress for cast iron is 10 N/mm2. Draw a neat sketch of the coupling.[16]

8 A) What is concentric spring? Explain its significance in automobiles.(B) Design a coil spring for a spring loaded governor to give a deflection of 55 mm under an axial load of125 N. The mean radius of the coil is 30 mm and the wire diameter is 10 mm. Take G = 0.8x105N/mm2.Check the spring for buckling. Give a neat sketch of the spring in the uncompressed state.[6+10]

2. IMPORTANT QUESTIONS

ImportantQuestionsforSemesterEndExam

Subject: DMM-I Subject Code: 55019



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UnitS No Important Questions Appearedin year

I 01 (A) List-out the different types of stresses, to which a screwed fastener is generallysubjected.(B) The head of a steam engine cylinder of 600 mm diameter is subjected to steampressure of 1.3N/mm2. The head is held in place by 16 bolts of M36 size. A softcopper gasket is used to make the joint steam tight. Determine the stress induced in

the bolts. [6+10]

NOV 2010(Reg)

VIII 02 A helical spring is subjected to loads ranging from 2kN to 2.5kN. The axialcompression of the spring over the above load range is approximately 5 mm.

Assume spring index of 6, design the spring.

DEC 2011(Reg)

V 03 (A) What are the applications of a cotter joint?(B) Describe the design procedure of a gib and cotter joint.

DEC 2011(Reg)

IV 04 (A)Define stiffnee for an axially loaded member.(b) A rod made of aluminum alloy (E = 72 GPa) has length 500 mm and diameter10 mm. What are its tensile stistiffness and flexibility?(c) A simply supported beam of rectangular cross section having depth three timeswidth, is subjected to a point load of 20 kN at 300 mm from the left support.The span of the beam is 700 mm. Determine the dimensions of the section, ifthe allowable strength of the material is 200 MPa.

DEC 2011(Reg)

IV 05 (A)Explain the procedure used to determine the number of rivets in single anddouble shear.(b) A triple riveted lap joint with zig-zag riveting is to be designed to connect twoplates of 6 mm thickness. Determine the diameter of rivets, pitch of rivets anddistance between the rows of rivet. Indicate how the joint will fail. Assume:t = 120 MPa; = 100 MPa and c = 150 MPa.

DEC 2011(Reg)

VI 06 Compare the weight, strength, and Stiffness of a hallow shaft of the same externaldiameter as that of solid shaft. The inside diameter of the hallow shaft being 0.6times the external diameter. Both the shafts have same material and length. [15]

DEC 2011(Reg)

VII 07 A Flanged protective type coupling is required to transmit 50 kW at 2000 rpm.Find:(a) Shaft diameter if the driving shaft is hollow with di /do = 0.6 and driven shaft

is a solid shaft. Take =100 MPa.(b) Diameter of bolts, if the coupling uses four bolts. Take t = c =70 Mpa; =25 MPa. Assume pitch circle diameter as about 3times the outside diameterof the hollow shaft.(c) Thickness of the flange and diameter of the hub. Assume c =100 MPa and =12 Mpa.(d) Make a neat free hand sketch of the assembled coupling showing a longitudinalsectional elevation with the main dimensions. The other dimensions assumedsuitably.

DEC 2011(Reg)

VIII 02 (A) Derive an expression for stresses in helical springs of circular wire.(B) A helical spring is made from a wire of 8 mm diameter and has outside diameterof 80 mm. If the permissible shear stress is 360 N/mm2 and modulus of rigidity 84KN/mm2, and the axial load which the spring can carry and the deflections per active

turn. [6+10]

NOV 2010(Reg)

III 03 (A) What is caulking and why is it necessary?(B) A double riveted lap joint is made between 20 mm thick plates. The rivet diameterand pitch are 30 mm and 80 mm respectively. If the ultimate stresses are 450N/mm2 in tension and 350 N/mm2 in shear and 540 N/mm2 in crushing, nd theminimum force per meter, which will rupture the joint. If the above joint is subjected toa load such that the factor of safety is 3, nd out the actual stresses developed in theplates and the rivets. [6+10]

NOV 2010(Reg)

V 04 (A)Describe the purpose of Gib in cotter joint? What are the applications of cotterjoints?(B) Design and draw a cotter joint to support a load varying from 3 KN incompression to 4 KN in tension. The material used is carbon steel for which thefollowing allowable stresses may be used. The load is applied statistically. Tensile

stress = compressive stress = 500 N/mm2, shear stress = 350 N/mm2 and crushingstress = 900 N/mm2.

[ 6+10]

NOV 2010(Reg)



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VII 05 Design a muff coupling for transmitting 100 kW power at 300 rpm. The design shouldresist 45% overload. The material of the key and shaft is having allowable shearstress as 65 N/mm2, whereas for mu the shear stress should not exceed 10 N/mm2.

Also prepare proportioned sketch of the coupling.[16]

NOV 2010(Reg)

II 06 (A) Explain various factors influencing the endurance limit.(B) A circular bar of 1000 mm length is supported freely at it two ends. It is acted

upon by a central concentrated cyclic load having a minimum value of 50 KN and amaximum value of 100 KN. Determine the diameter of the bar by taking a factor ofsafety of 1.6, size effect of 0.85, surface finish factor of 0.88.The material propertiesare given by

NOV 2010(Reg)

VI 07 A solid shaft is supported on two bearings 2 meters apart and rotates at 500 rpm.Two pulleys whose diameters are 800 mm and 600 mm respectively are mounted onthe shaft at distances 400 mm and 1200 mm respectively to the right of the left handbearing. A 20 involute gear of 300 mm diameter is keyed to the shaft at a distance of200 mm to the left of right hand bearing. A power of 50 kW is supplied to the gear,out of which 30 kW is transmitted by bigger pulley weighing 600 N and 20 kW istransmitted by the smaller pulley whose weight measures 450 N. The drive frombigger pulley is vertically downward and from smaller pulley is horizontal. The tensionratio for both the pulleys is 2. Design the shaft for the working stress of 45 N/mm2 in

shear and 80 N/mm2 in tension. Assume the combined shock and fatigue factors fobending and torsion as 2 and 1.5 respectively. Strength is 650 N/mm2, yield strengthis 500 N/mm2 and endurance strength is 350 N/mm2.[6+10]

NOV 2010(Reg)

I 08 (A) What are the different mechanical properties of engineering materials.

(B) Write notes on any four ferrous materials giving their constituents andapplications.

[8+8]

NOV 2010(Reg)

III 09 As shown in a welded joint subjected to an eccentric load of 20 KN. The welding isonly on one side. Determine the uniform size of the weld on the entire length of twolegs. Take permissible shear stress for the weld material as 80 MPa.

NOV 2010(Reg)

III 10 A 200 mm X 150 mm X 10 mm angle is joined to a frame by two parallel fillet weldsalong the edge of 200 mm length. If the angle is subjected to a static load of 200 kN,find the length of weld at the top and bottom. The allowable shear stress for staticloading may be taken as 75 Mpa.

NOV 2010(Reg)

III 11(A)Sketch and discuss the various types of welded joints used in pressure vessels. NOV 2009(Reg)

11(B)Differentiate between a cotter joint and a knuckle joint. NOV 2009(Reg)

11(C)A shaft is supported on two bearings placed 0.6m apart. The shaft supports a 0.5mdiameter pulley, located at 0.25m to the right of the left hand bearing, and the beltdrives a pulley located directly below the shaft. Another pulley of 0.4m diameter is

located 0.125m to the right of the right hand bearing, and the belt is driven by apulley located horizontally to the right. The coefficient of friction for the belt drive is0.3, and the angle of contact may be taken as 1800. The maximum tension in thebelt on the smaller (0.4 m diameter) pulley is 3.6kN. Assuming permissible shearstress for the shaft material as 42MPa, determine the shaft diameter

NOV 2009(Reg)

III 12(A)A bracket is riveted to a column by 6 rivets (A,B,C,D,E and F) of equal size as shownin Figure \ref{fig1S08} The centers of rivets A,B,C are on the same vertical line andthe centers of D,E , F are on the another vertical line. The centers of A, F are on thesame horizontal line. The centers of B, E are on one horizontal line and the centersof C, D are on another horizontal line. The vertical distance between A, B and B, Care 75 mm and 75 mm respectively. The horizontal distance between C, D is 100mm. It carries a load of 60 kN at a horizontal distance of 200 mm from the center of

the column. If the maximum shear stress in the rivet is limited to 150 MPa, find thediameter of the rivet.

NOV 2009(Reg)



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12(B) NOV 2009(Reg)

V 13 (A) Which material is generally used for a cotter? Why the taper is given on a cotter?(B) Two rod ends are to be joined by means of a cotter joint, by using a sleeve andtwo cotters. The joint is subjected to an axial load of 120 KN, which alternatelychanges slowly from tension to compression. The permissible stresses for the rods,sleeve and cotter material are 100 N/mm2 in tension, 80 N/mm2 in shear, and 150 N/mm2 in compression. [6+10]

NOV 2010(Reg)

II 14 (A) Explain the importance of fluctuating stresses in design of machine elements.(B) A hot rolled steel shaft is subjected to a torsional moment that varies from 430 N-m clockwise to 210 N-m counterclockwise and an applied bending moment at acritical section varies from 540 N-m to -320 N-m. The shaft is of uniform cross-section and no key way is present at the critical section. Determine the required shafdiameter. The material has an ultimate strength of 650 N/mm2 and yield strength of450 N/mm2. Take the endurance limit as half the ultimate strength, factor of safety as2, size factor as 0.85 and surface finish factor as 0.62.[6+10]

NOV 2010(Reg)

III 15 (A) Explain the terms i. Diagonal pitch & ii. Margin in connection with riveted joints(B)A triple riveted lap joint with chain riveting is to be designed to connect two platesof 8 mm thickness. Determine the diameter of the rivet, pitch of rivets and distance

between the rows of the rivets. Indicate how the joint will fail. Also, find the efficiencyof the joint. The permissible stresses are 150 N/mm2 in tension, 120 N/mm2 in shearand 130 N/mm2 in crushing. [6+10]

NOV 2010(Reg)

VII 16 Design a rigid sleeve coupling to connect two shafts and to transmit 28.5 kW powerat 1200 rpm. The allowable shear stress in the material of the shaft is 75 N/mm2.The material of the shaft and key is same and the coupling is required to transmit25% overload. The material of the sleeve is cast iron, the allowable shear stress fowhich is 18 N/mm2. Make a neat sketch of the designed sleeve coupling showingside view and sectional elevation.[16]

NOV 2010(Reg)

I 17 (a) State the advantages of preferred numbers.(b) Design a suitable diameter for a circular shaft to transmit 120 kW power at 350rpm. The shear stress in the shaft is not to exceed 35 N/mm2 and the maximum

torque exceeds the mean by 50%. Also find the angle of twist in a length of 3 m.Take G= 200 KN/mm2. [6+10]

NOV 2010(Reg)

VI 18 (A) Deduce design equation for a hollow shaft subjected to bending moment M,torque T and axial thrust Fa.(b) Determine the diameters of a hollow shaft, transmitting a torque of 450 N-m, andsubjected to a bending moment of 600 N-m. Assume the shock and fatigue factors intorsion and bending as 1.2 and 1.3 respectively. The ratio of outer to inner radii is1.5. Find the diameter, if the shaft is a solid one. Compare the weights of hollow andsolid shafts. [6+10]

NOV 2010(Reg)

VIII 19 (A) What is concentric spring? Explain its significance in automobiles.(B) Design a coil spring for a spring loaded governor to give a deflection of 55 mmunder an axial load of 125 N. The mean radius of the coil is 30 mm and the wirediameter is 10 mm. Take G = 0.8x105 N/mm2.Check the spring for buckling. Give aneat sketch of the spring in the uncompressed state.[6+10]

NOV 2010(Reg)



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IV 20 (A) Define the terms(a) pitch ,(b) Nominal diameter Root diameter corresponding to bolted joints.

(B) A flanged bearing is fastened to a frame by means of 6 bolts spaced equally on550 mm bolt circle. The diameter of bearing flange is 750mm and a load of 200 KNacts at a distance 350 mm from the frame. Determine the size of the bolts, assumingtensile stress as 120 N/mm2 for the bolts.[6+10]

NOV 2010(Reg)

I

21

(a) Define Rigidity". What are the requirements to design a solid shaft forrigidity?(b) A shaft made of ductile material is 6 m length between bearings and transmits 15kW at 900 rpm. It is also subjected to a bending moment of 180 N-m. Determine thediameter of the shaft by taking the working stress in the shaft in shear as 75 N/mm2.

Assume that the shaft is applied with medium shocks.[6+10]

MAY 2011(Supple)

III 22 (A) Explain what is meant by single shear and double shear?(B) A 60 mm diameter solid shaft of length 250 mm is welded at one end to a at platewhile the other end is subjected to a load of 100 KN acting vertically downwards.Determine the size of the weld, if the permissible shear stress in the weld is limited to120N/mm2. [6+10]

MAY 2011(Supple)

II 23 A steam engine of effective diameter 400 mm is subjected to a steam pressure of 2

N/mm2. The cylinder cover is connected by means of 6 bolts having yield strength of450 N/mm2 and endurance limit of 275 N/mm2. The bolts are tightened with an initialpre load of 2.5 times that of steam force. A soft copper gasket is used to make a leakproof joint. The stress concentration factor is 2.5 Determine the size of the bolts.[16]

MAY 2011

(Supple)

VIII 24 (a) Generally how the springs are Classified? Indicate the different types of springsby sketches.(b) A truck spring has 12 leaves and is supported at a span length of 1 m, with acentral band of 80 mm wide. A load of 6kN is applied at center of spring whosepermissible stress is 300 N/mm2. The spring has a ratio of total depth to width ofabout 2.5. Determine the width, thickness, deflection and length of all leaves.[6+10]

MAY 2011(Supple)

VII 25 Design a cast iron protective type flange coupling to transmit 16 kW at 900 rpm from

an electric motor to a compressor. The service factor may be assumed as 1.5. Thefollowing permissible stresses may be used: Shear stress for shaft, bolt and keymaterial is 60 N/mm2, Crushing stress for bolt and key is 70 N/mm2, Shear stress focast iron is 10 N/mm2. Draw a neat sketch of the coupling.[16]

MAY 2011

(Supple)

I 26 (A) State the advantages of preferred numbers.(B) Design a suitable diameter for a circular shaft to transmit 120 kW power at 350rpm. The shear stress in the shaft is not to exceed 35 N/mm2 and the maximumtorque exceeds the mean by 50%. Also nd the angle of twist in a length of 3 m. TakeG= 200 KN/mm2. [6+10]

MAY 2011(Supple)

II 27 A steel cantilever is 20m long. It is subjected to an axial load which varies from 15 N(compression) to 45 N (tension) and also a transverse load at its free end which

varies from 8 N up to 12 N down. The cantilever is of circular cross section. It is ofdiameter 2d for the first 5m and of diameter d for the remaining length. Determine itsdiameter taking a factor of safety of 2. Assume the following values: Yield stress is3300 N/mm2, Endurance limit in reversed loading is 3000 N/mm2 ,Correction factoris 0.7 in reversed axial loading and 1.0 in reversed bending, Stress concentrationfactor 1.44 for bending and 1.64 for axial loading, Size effect factor 0.85, Surfaceeffect factor 0.90, Notch sensitivity index 0.90. [16]

MAY 2011(Supple)

VI 28 (A) A 1.5 m diameter cast iron pulley is mounted on a 100 mm diameter shaft bymeans of sunk key of size 50 mm 50 mm 150 mm. Determine the maximum torquethat can be transmitted by the pulley, if the permissible shear and crushing stressesfor the key are 65 and 125 N/mm2 respectively.(B) Design a sleeve and cotter joint to connect two rods to transmit a tensile force of130 KN. Same material is used for the rod , sleeve and the cotter. The allowable

tensile stress is 95N/mm2, compressive stress is 200 N/mm2 and shear stress is 45N/mm2. [6+10]

MAY 2011(Supple)

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LP_III_I_MECH_55019(2012-2013)

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