Design of a Union of Rod

UNIVERSITY OF NUEVA CACERESCOLLEGE OF ENGINEERINGCITY OF NAGA

Plate No. 1ME 414(MACHINE DESIGN I)

DESIGN OF A UNION OF ROD JOINT

Submitted by:EMERSON A. TUBALEBSME EN 94 - 11407

Submitted to:ENG'R. MANUEL L. BALAQUIAO(Instructor)

AUGUST 29, 2012

August 29, 2012

ENGR. MANUEL L. BALAQUIAOCollege of EngineeringUniversity of Nueva CaceresCity of Naga 4400

Dear Sir,GREETING OF PEACE! This project design entitled DESIGN OF A UNION OF A RODS is submitted to comply with the partial requirement in ME 414 Machine Design 1.The sole purpose of this design is to know its uses, especially in machines.The subject covers the strength of materials; the stress developed while in torsion, in compression and shear when where the materials will collapse.Under this purpose a design is, made to cover the subject matter completely and thoroughly. The solution and computation of all the size and allowances; the drawn to scale parts of the union of rods, the orthographic sectional, exploded, and isometric views are also shown and included in this design.I hope that this design will meet with your approval.

Respectfully yours,

EMERSON A. TUBALE EN 94-11407

iiTABLE OF CONTENTS

Title Page ---------------------------------------- iLetter of transmittal----------------------------------- iiTable of Contents ---------------------------------- iiiAcknowledgement----------------------------------- ivDesign Problem---------------------------------------- 1Analysis and Solutions----------------------------------- 4Summary of Computed and Adjusted Value-------------------- 32Glossary-------------------------------------------- 33Bibliography---------------------------------------- 34Working Drawing

iiiACKNOWLEDGEMENTThis design could hardly have been possible without the direct and indirect help of many. I feel compelled to mention those who had a hand in getting this going, who gave me input and help along the way. So I would lie to extend my sincere thanks to the person who in one way or another helped in the completion of this project.Especially to my parents for giving me their financial and moral support with them, I couldnt do it alone.To my Ate Gellete and Kuya Mac-Mac for helping me in making this in computer and giving them courage to do this project.To my classmate, friends and Professor Engr. Manuel L. Balaquiao whose given ideas and thoughts, contributed for the organization of this work.I would be remiss without acknowledging my girl friend Abigail for their inspiration, assistance, moral support and understanding. Without her, this report would not be possibleLastly to the almighty God who gave me this wisdom and spiritual strength to accomplish this task.My appreciation would be grateful acknowledgement of their invaluable assistance and support.

Emerson

ivDESIGN PROBLEMDesign union-of-rods joint to that shown for reserving load and material given in the accompanying table. The taper of the cotter is to be in. in 12 in, (see 172) A). Using design stress based on yield strengths. Determine all dimensions to satisfy the necessary strength equation. B). Modify dimension as necessary for good proportion being careful not to weaken the joint.C). Decide upon tolerance and allowances for loose fit.D). Sketch to scale each part of the joint showing all dimension needed for manufacture, with tolerance and allowances.

Figure:

1PROBLEM No.LOAD,AISI NO. AS ROLLED

NO. 503500 lbs.1030

Strength base on yield strengthFrom table 1.1 p. 20 (factor of safety)For repeated reversed gradual (mild shock)N = 4, based on yield strengthF = 3500 lbs.From table AT 7Sy = 51 ksiSy = 51000 psiFor the design stresses Ss = 0.5 Sy to 0.6 SyUsed:Ss = = Ss = 6375 psi

2For Tension: For Compression: Ss = Ss = St = Sc = Sc = 12750 psi

3ANALYSIS AND SOLUTIONA). Failure may occur to both end of the joint due to tensile force.St = For the Area of the circle = A circle = = = 12 in.For standard fraction: (p.32) Between to in. = 0.5625 in 0.5912 = in. = in. = 0.625 in.

d = in. or in.

4Check if in. (0..) can be use 100 = 4.85% > 4- 5%

.. Use:d = in.

For the figure:Fig. 1

5B). The tension load may cause tearing across the cotter hole.Fig. 2

St = Where:A = Area of the rod minus the area of the cotterA= - e (t)F= St ( - et) equation 1By crushing the cotter bearing into the end surface of the rodSc = F = Sc AWhere:A= e (t)F= Sc (et) equation 2

6Equating the equation 1 and 2F = FSince Sc = StSc (et) = Sc ( - et)et = - et4t (e) = 4t (e) = e (4t + 4t = 8t = e = equation 3Substituting equation 3 to 2e = F = Sc tF = Sc =

7Substituting the value: t = = t = 0.3283 in.For standard fraction: (p.32) Between to

in. = 0.3125 in. 0.3283 = in. = in. = 0.375 in.

t = in. or in.

Check if in. (0.3125 in.) can be use 100 = 4.81% > 4- 5%.. Use:t = in.

8For e:Solving for e:e = from equation 3

Substitute the value of t to the equation 3e = e = 0.9549 in.

For standard fraction: (p.32) Between to

in. = 0.875 in. 0.9549 = in. = 1 in.

e = in. or in.

9Check if in. (0.875 in.) can be use 100 = 8.80% > 4 - 5%

.. Use:e = in.

Fig. 3

10C). The socket may fail across the cotter hole by a tensile force.Fig. 4

F = Sc AWhere:A = Area of the socket minus the area of rodF= St [ - ) - (m-e) t]4F= St [ - ) 4t (m-e)]= - ) 4t (m-e)Substituting the value= - ) 4t (m-e)= - 4(0.375) (m - 1)1.0980 = -3.1416) 1.5 (m - 1)

111.0980 = - 3.1416 1.5m + 1.51.0980 -1.25 + 3.1416 = - 1.5m2.9896 = - 1.5m - 1.5m 2.9896Using quadratic equation and getting positive valuem = Where:a = b = 1.5 c = -2.9896

m =

m = 1.2032 in.

12For standard fraction: (p.32) Between to

in. = in. 1.2032 = in. = in. = 1.25 in.

m = in. or in.

Check if in. can be use 100 = 5.81% > 4 - 5%

.. Use:m = in.

13D). By crushing the collar of the rod. Fig. 5

F = Sc AWhere:A = - ) = + Substitute the value

k =

k = 1.1617 in..

14 For standard fraction: (p.32) Between to in. = in. = 1.125in. 1.1617 = in. = in. = 1.25 in k = in. or in

Check if in. (1.125in.) can be use 100 = 3.16% < 4 - 5%

.. Use:k = in.

15E). By crushing the cotter bearing surface in the socket.Fig.6

Sc =

Where:A = t (D-e)F = Sc AF = Sc [t (D-e)]D = + e

Substitute the value

D = + 1

D = 1.7320 in.


1 in. = 1.625 in. 0.7320 = 1 in. = in. = 1.75 in.

D = 1 in. or in.

Check if 1 in. can be use 100 = 6.17% > 4 - 5%

.. Use:D = in.

17F). The cotter may be sheared off by the rod and the socket.Fig. 7

F = Ss AA = ctSince it will be shearedA = 2 (c t)F = Ss (2 c t)c = Substituting the value

c =

c = 0.7320 in.


in. = 0.6875 in. 0.7320 = in. = in.

c = in. or in.

Check if in (0.6875 in.) can be use 100 = 6.08% > 4 - 5%

.. Use:c = in.

19G). By shearing the rod end.

Fig. 8

F = Ss AWhere:A = 2 f eF = Ss (2 f e)f =

Substituting the valuef =

f = 0.2745 in.


in. = 0.25 in. 0.2745 = in. = 0.3125 in.

f = in. or in.


.. Use:f = in.

21H). by shearing the socket end Fig. 9

F = Ss AWhere:A = 2 b (D - e)F = Ss [2 b (D - e)]b = Substituting the value

b =

b = 0.3660 in.


in. = in. 0.3660 = in. = in = 0.375 in.

b = in. or in.


.. Use:b = in.

23I). By shearing off the collar in the rod end.Fig. 10

F = Ss AWhere:A = () (e) (a)F = Ss ( e a)a = Substituting the value

a =

a = 0.1748 in.

24For standard fraction: (p.32) Between to in. = 0.1563 in. 0.1748 = in. = in. = 0.1875 in.

a = in. or in.

Check if in. (0.1563 in.) can be use 100 = 10.58% > 4 - 5%

.. Use:a = in.

25FOR THE TAPER OF THE COTTERFrom the Problem, the taper or the cotter is in. in 12 in.

Fig. 11

For the height and the cotter(D + 1) = 1.75 + 1 = 2.75Assume that the length of the cotter is equal to 2.75 in. = x = x = 0.1146 in.

26For standard fraction: (p.32) Between to in. = 0.09375 in. 0.1146 = in. = in. = 0.125 in.

x = in. or in.

Check if in. (0.09375 in.) can be use 100 = 18.19% > 4 - 5%

.. Use:x = in.

27J). For the tolerance and allowancesCotter and Hole RC 8Value of t = in. = 0.375 inNominal SizeHoleShaft

0.24 0.40+ 2.20- 3.0- 4.4

* The number given are the standard limits in thousands of inch multiply by Hole Tolerance: 0.0022 0 = 0.0022 in.Cotter Tolerance: - 0.003 (-0.0014) = 0.0014 in.Allowances:0 (-0.003) = 0.003 in.

+Hole toleranceHole: Nominal Size - 0.0000

+0.0000Cotter: (Nominal Size Allowance) -Cotter Tolerance

28 +0.0022 in.Hole: 0.375 in - 0.0000 in.

+0.0000 in.Cotter: (0.375 - 0.003) in. -0.0014 in.

+0.0000 in.Cotter: 0.372 in. -0.0014 in.

Limit DimensionHole: 0.375 in. to 0.3772 in.Cotter: 0.3095 in. to 0.3706 in.

Preferred Method

29Rod and Socket Hole RC 8Value of e = 1 in. Nominal SizeHoleShaft

0.71 1.19+ 3.50- 4.5- 6.5

*multiply by Socket Hole Tolerance: 0.0035 0 = 0.0035 in.Rod Tolerance: - 0.0045 (-0.0065) = 0.002 in.Allowances:0 (-0.0045) = 0.0045 in. +Hole toleranceHole: Nominal Size - 0.0000 +0.0000Cotter: (Nominal Size Allowance) - Cotter Tolerance

30+0.0035 in.Socket Hole: 1 in.- 0.0000 in.+0.0000 in.Rod: (1 -0.0045) in. -0.002 in.

Limit DimensionHole: 1 in. to 1.0035 in.Cotter: 0.9955 in. to 0.9935 in.

Preferred Method

31K). Summary

SUMMARY OF COMPUTED AND ADJUSTED VALUES

PartsComputed Values(in.)Adjusted Values in Fraction. (in.)Adjusted Values in Decimal. (in.)

d

t

e11

m11

k11

D111.75

c0.75

f

b

a

x0.125

32GLOSSARY

Allowance - It is the difference in size, which in running fits is the maximum specified difference between the dimensions of the pin and the hole.Allowable Stress - The stress used in design for a safe one to use for computations if failure is not occur.Compress - Flattened from side to side.Cotter - A key of wedge, used to fasten parts of machinery together, as a wheel on its shaft.Design Factor - Is a number that is divided into a criterion of strength in order to obtain design criteria.Ductility - Is that property that permits permanent deformation before fracture on tension.Design stress (Working stress) - It is a design, used in such a way all criteria of strength are modified. Machine design It is involve the calculation of the forces acting on different part of the machines.Stress - The state of an elastic body under conditions of strain expressed quantity as force applied per unit area.Shear - A deformation within a body on which two adjacent planes tend to move in a parallel direction relative to one another while remaining parallel.Tension Is a force tending to cause extension of a body, or the shape of an extended elastic object.Tolerance - It is the stated permissible variation of the size of a dimension.Strength of material - It is the capacity to resist the action or applied forces.Ultimate strength or tensile strength - The highest point on the stress strain curves, is the maximum load divided by the original before straining occurs.Yield strength - Is the stress for a specified deviation from the straight part of the stress - strain curve.

33B I B L I O G R A P H Y

Faires,Virgil Moring, Design of machine Elements, 4th Edition, New York: Mcmillan Publishing Company, Inc. 1965.

Ferdinand L. Singer/Andrew Pytel Strength of Materials 3rd Edition The Harpers and Row Company, New York, 1989.

Doughtie,Venton Levy, Design of Machine Members, 4th Edition, New York: Mcgraw-Hill Book Company, Inc. 1964. Clark, Donalds,Engineering Materials and Processes , 3rd Edition, International Textbook Company, Pennsy Lvania, C 1967.

Parker, Sybil P., McGraw-Hill Dictionary of Engineering , 3rd Edition, McGraw-Hill Book Company, New York, C 1984.

34

WORKING DRAWINGSSCALE 1:1NOTE: ALL DIMENSION ARE IN INCHES

Machine Design 1 Criteria for Grading

Name: Emerson A. Tubale

Technical Report

Format 10%_________ Contents 30%_________

Working Drawings

Standard Used 10%_________ Completeness 30%_________

Meeting the Deadline 20%_________

Engr. Manuel L. BalaquiaoDate: 8/24/12

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Design of a Union of Rod