DEPARTMENT OF MECHANICAL ENGINEERING

INSTITUTE OF TECHNOLOGY

BANARAS HINDU UNIVERSITY

VARANASI-221005

CERTIFICATE

Certified that the dissertation work entitled “Analysis and

Simulation of Hydroforming Process” being submitted

by Mr.Bathina Sreenivasulu (05030628) in the partial

fulfillment of the requirements for the award of Master of

Technology in Mechanical Engineering (Production

Engineering.) at the Institute of Technology, Banaras Hindu

University, Varanasi, is a record of the student’s own work

carried out by him. The matter embodied in this project

report has not been submitted for the award of any other

degree or diploma.

(Supervisor) (Forwarded by) Dr. Santosh Kumar Prof. S. K. SharmaReader, Head,Dept. of Mechanical Engg. Dept. of Mechanical Engg.IT-BHU, IT-BHU,

Varanasi, India. Varanasi, India.

ACKNOWLEDGEMENT

I have great pleasure in expressing my deep

sense of gratitude and indebt ness to Dr. Santosh

Kumar for his continuous guidance, invaluable

suggestions, personal encouragement and help

during the course of my work without which it would

not have been possible to conclude the work. I

whole-heartedly confess with great pleasure the free

and frank academic discussions I had with them,

which used to be lively many a time. Their human

nature and personal concern for me touched my

heart. This will make a deep impression in my mind

throughout my life.

I am obliged to Dr.Santosh kumar for giving

me a free hand use computational facility in his

chamber during the course of this work.

I am grateful to Dr. S. K Sharma, Professor and

Head, Department of Mechanical Engineering, I.T.-

B.H.U for his cooperation in completion of the

dissertation.

I am greatly indebted to my Father, brothers and

sisters who encouraged me to go for higher studies.

Last but not least I express my sincere thank to

my friends G. Venkataih, A. Srinivas, Sunil kumar

reddy, J. Srinivasulu, Manish gunjan, Vibhanshu,

Vivek, Harsha, Deeraj and those who directly or

indirectly help me to complete this work.

Date : May 11, 2007

Place : Varanasi. Bathina

Sreenivasulu

Dedicated

toMy Father

Ab

Cont

LIST OF SYMBOLS

b Width of the die

d0, Di Initial tube diameter

Do Tube outer diameter

dp, Dp Protrusion diameter

E Modulus of Elasticity

Fa Axial force

FSealing Sealing force

Fs Sealing force during forming

Ffriction Friction force

G Modulus of Rigidity

H Branch height

L, l Initial tube length

Ld Die length

Lf, lf Free tube length

Pi Internal pressure

(Pi)y Internal pressure at yielding

(Pi)u Internal pressure at bursting point

R1, Rd Corner radius

S Axial stroke

t, t0 Initial tube thickness

y Yield strength

u Ultimate strength

ρ Density

LIST OF TABLES

1.1 Major CAPP applications in manufacturing process 6

4.1 Material properties of work piece 27

4.2 Properties of die 27

5.1 Process plane for specified inputs 41

5.2 Material properties of some hydroformable material 43

5.3 Lubricants used in tube hydroforming 45

6.1 Branch height comparison-experiment and simulation results 47

6.2 Process plane for T-branch tube hydroforming 64

6.3 Process plane for X-branch tube hydroforming 65

LIST OF FIGURES

2.1 Classification of hydroforming 8

2.2 Process principle of tube hydroforming 9

2.3 Most common failures and limits in tube hydroforming 10

2.4 The principle of tube hydroforming

(a) Original tube shape 11

(b) Final tube shape (before loading) 11

2.5 Failures in tube hydroforming 12

2.6 To avoid buckling, these rules should be followed during

tool design and tube material selection 12

2.7 The limits and the working range in tube hydroforming 13

2.8 Tube hydroforming consists of free forming and calibration 14

2.9 The selected loading path determines the deformation mode 15

and the intermediate shape of the deforming tube

3.1 Constituent of CAD tool 17

3.2. Implementation of CAE process 21

4.1 Model of tube blank 24

4.2 Model of die for T-branch 25

4.3 Axial Plunger 25

4.4 Counter plunger 25

4.5 Model of die for X- branch 26

4.6. Experimental and simulation load paths 28

5.1 System flow chart for proposed CAPP system 33

5.2 To avoid buckling, these rules should be followed during tool

design and tube material selection. 37

5.3 Flow chart describing the procedure used to determine the

coefficient of friction using the LDH test 46

6.1 Simulation of T-Branch 48

6.2 Wall thickness distribution along the curvilinear length,

from the tube centre to tube 49

6.3 Load prediction 49

6.4 Velocity distribution for T- branch 50

6.5 Velocity distribution for X- branch 51

6.6 Damage for T- branch tube hydroforming 52

6.7 Damage for X- branch tube hydroforming 53

6.8. Effective strain during T-branch tube hydroforming 54

6.9. Effective strain during T-branch tube hydroforming 55

6.10 Effective stress distribution for T-branch tube hydroforming 56

6.11 Effective stress distribution for X-branch tube hydroforming 57

6.12 Effects of contact friction coefficient on maximum branch height 58

6.13 Effects of contact friction coefficient on wall thickness variation 58

6.14 Effects of internal pressure on maximum branch height 59

6.15 Effects of internal pressure on wall thickness variation 60

6.16 Effects of variation of axial plunger movement on the maximum

branch height 60

6.17 Effects of variation of axial plunger movement on wall thickness

variation 61

6.18 Formation of wrinkles 62

6.19 Burst formation at the top of the branch 63