Calculation for tube HForming Tính toán thiết kế công nghệ dập thủy tĩnh phôi ống (IHU)

Tài liệu cung cấp cho mọi người phương thức tính toán cũng như định hướng thiết kế trong công nghệ dập thủy tĩnh phôi ống. Trong đó có nêu một số tính toán và thiết kế của một số dạng biên dạng ống cơ bản.

Pipe products – Various shapes of pipes

Connecting parts Cam shaft Crank shaft

Classification

HYDROFORMING OF TUBE

with one axis load

HYDROFORMING OF TUBE

with more axis loads

Horisontal force, counter force, bending force, force to close the dies

Stress state by Hydroforming of tube

Stress state of tube hydroforming with one axis load

Direction of long the axis

Radius direction

Tangential direction

Stress state of tube hydroforming with vertical and horisontal loads

Stress state of tube hydroforming with horisontal and bended loads

Calculation the process parameters

Calculation the process parameters

p – fluid pressure for shaping of tube

Fs – counter force

Fc – closing force

Fa, Fb, Fp, Fs – Forces for forming process

(axial Force, bending

Force…)

Calculation the process parameters in case of one axis load

The equation to describe the shaping of tube:

i Z

Z

t

p R

R Radius of horizontal and vertical sections of tube

ti – currently thickness of tube

Due to Rz is very big, hence:

Base on plasticity rule   S Where S - Yield stress

Therefore, the minimal fluid pressure needed for shaping of tube is:

The material has tensile strength B

d

t 2

Calculation the process parameters

in case of more axis loads

p – fluid pressure

Fs – counter force (Counterholding force)

Fc – closing force (Press force)

Fa – axial Force

Process parameters are:

1 Calculation fluid pressure p:

In the area of knot (vung dinh

vau noi) the work piece will be

strongly thined down That is

serious area to create the

crack





' R

t

B max







' R

t

S min

d / t.

15 , 1

13 , 0 p

min  S  S

As experiment:

Needed fluid pressure for shaping of tube:

Fluid pressure by cracking of tube:

2 Calculation axial force F a :

Axial forces are very important during shaping process They assist the work pices flowed, displaced in to the area of knot

t 2 d

Z i

dp p 2 F

i S

2 i 2

t.

2 ' d

'

d ln

8

'

d t.

t '

d 4

3

4

t d

d p F

 =1,15 for flat stress stated’ – diameter of knot

Calculation the axial punch force F P

p F

2 i P

Calculation the friction force on the contact surface

between work piece and die

' d

l

t t.

2 d

p

d

t p

' d l d 5 ,

0 t

2 d

d ln

8

d t

d 75 ,

0 4

d p

2

S a

Finally, the axial force cam be calculate as follows:

Where l, t – length and thickness of tube by finishing of process

d’ – diameter of knot

3 Calculation counter force (Counterholding force) F s :

t.

' d '.

F 4

'

d

2 y

d

4 Calculation closing force (press force) F c :

 - contact stress on the contact surface

Si - area of projection (dien tich hinh chieu)

For the T-Part, we have:

t p

Where li, hi, ti – currently length of tube, currently height of knot,

currently thickness of tube

n – number of knot

N 210

, mm /





' R

t

B max

d / t.

15 , 1

13 , 0 p

min  S  S

Needed fluid pressure for shaping of tube:

Fluid pressure by cracking of tube:

Calculation fluid pressure p:

2 min 0 , 13 210 1 , 15 210 2 / 30 43 , 4 N/mm

2 / 26 2

/ ' d '

R    

We have:

2 max 340 2 / 13 52 , 3 N/mm

(d = 32 mm – 2 mm = 30 mm)

i S

2 i 2

t 2 ' d

'

d ln

8

'

d t

t '

d 4

3

4

t d

d p F

15 , 1

30 ln

8

30 2

2

30 4

3 210

15 ,

1 4

2 32

32 4 , 43 F

2 2

2

Tons 5,1

N 51336

2 i p

, 2 F

N

26710 4

2 2

32

4 , 43 F

p

2 p

2

' d

l

t t.

2 d

p

d

i i

312018 F

30

2

' 30

50

t 2 2 30

210

15 ,

1 4

, 43

30 16 , 0

5,1 2,7

F F

d

N 12841 F

2 2 30

340 7

, 0 6

,

0 4

2 2

30

4 , 43 F

S

2 S

t p

113030 F

25 1 32

30 4 , 43 30

50 32

2 2 32

2 210

15 ,

1 4

, 43 F