http://creativecommons.org/licenses/by-nc-nd/2.0/kr/legalcodehttp://creativecommons.org/licenses/disclaimer-popup?lang=kr

LNG Pump

AC4C-T6

An Experimental Study on Material and

Fatigue Properties of AC4C-T6 at

Cryogenic Temperature for LNG Pump

Development

2008 2

LNG Pump

AC4C-T6

An Experimental Study on Material and

Fatigue Properties of AC4C-T6 at

Cryogenic Temperature for LNG Pump

Development

2008 2

.

2008 2

- I -

LNG Pump

AC4C-T6

LNG Pump -163 LNG (Loading)/

(Unloading) / .

LNG LNG

LNG /// .

LNG Pump

AC4C-T6

. -

, -

(-163) .

Pump

.

ANSYS

.

.

- II -

An Experimental Study on Material and

Fatigue Properties of AC4C-T6 at

Cryogenic temperature for LNG Pump

Development

ABSTRACT

LNG Pump is an equipment that loads and unloads LNG at

cryogenic temperature (-163). It is used in

storage/loading/unloading of LNG, as the main equipment in LNG

cargo tank.

In this thesis, it has been studied that the experimental results

on material and fatigue properties of AC4C-T6, and AC4C-T6 is

recommended as a main material of LNG pump. Material

properties such as elastic modulus, yield strength and ultimate

strength, fatigue strength properties i.e cyclic strength and cyclic

strain hardening exponent and S-N curve of AC4C-T6 have been

obtained by monotonic tensile test, incremental step test and

fatigue life test, respectively. Material properties and fatigue life

at -163 are compared with those of room temperature to

investigate the effect of temperature on the material properties

and fatigue strength. Also, the contraction rate at -163 is

measured to apply to design LNG pump.

In addition, FEA(Finite Element Analysis) model was developed

to predict results of material tests. Also, the results from FEA is

compared with those by experiments.

- III -

i

Abstract ii

iii

v

viii

1. 1

1.1 1

1.2 2

1.3 5

1.3.1 5

1.3.2 5

1.4 5

2. 7

2.1 7

2.1.1 7

2.1.2 7

2.2 Monotonic Tensile Test 8

2.3 Cyclic Stress-Strain Test 10

2.3.1 11

2.4 Cyclic Stress-Fatigue Life Test 12

3. 14

3.1 Material model 14

3.1.1 FEA model 14

3.1.2 14

3.2 FE Simulation 16

3.2.1 16

- IV -

3.2.2 16

3.2.3 17

4. 25

4.1 Monotonic stress-strain test 25

4.1.1 (Room Temperature) 25

4.1.2 (Cryogenic Teperature) 26

4.2 Cyclic stress-strain test 28

4.2.1 (RT) 28

4.2.2 (CT) 30

4.3 Cyclic Stress-Fatigue Life Test 32

4.3.1 (RT) 32

4.3.2 (CT) 33

4.4 35

5. 36

6. References 38

- V -

Fig.1 LNG 1

Fig.2 LNG Pump 1

Fig.3 LNG 2

Fig.4 LNG 2

Fig.5 LNG Pump LNG

3

Fig.6 LNG 4

Fig.7 Universal Testing Machine 7

Fig.8 Cryogenic Chamber 8

Fig.9 AC4C-T6 8

Fig.10 0.2% Offset Method 9

Fig.11 AC4C-T6 Monotonic Tensile Test

10

Fig.12 AC4C-T6 Monotonic Tensile Test

10

Fig.13 Incremental Step Test 11

Fig.14 Log-log plot of true cyclic stress versus true cyclic

plastic strain 12

Fig.15 S-N 12

Fig.16 Stress-strain behavior of BISO 14

Fig.17 Stress-strain behavior of BKIN 15

Fig.18 Stress-strain behavior of NLISO 15

Fig.19 Finite element model for analysis 17

Fig.20 BISO model at 20 17

Fig.21 BISO model at -165 18

Fig.22 BISO (K',n') 18

Fig.23 BKIN model at 20 19

- VI -

Fig.24 BKIN model at -165 19

Fig.25 BKIN (K',n') 19

Fig.26 NLISO model at 20 20

Fig.27 NLISO model at -165 21

Fig.28 NLISO (K',n') 21

Fig.29 Chaboche model at 20 22

Fig.30 Chaboche model at -165 22

Fig.31 Chaboche (K',n')22

Fig.32 Combined model at 20 23

Fig.33 Combined model at -165 23

Fig.34 Combined (K',n') 24

Fig.35 - 25

Fig.36 0.2% Offset method 26

Fig.37 - 26

Fig.38 - 27

Fig.39 CSS Test Hysteresis loop 28

Fig.40 CSS Curve 28

Fig.41 (K')

(n') 29

Fig.42 Cyclic Monotonic Stress-Strain Curve 29

Fig.43 CSS Test Hysteresis loop 30

Fig.44 CSS Curve 30

Fig.45 (K')

(n') 31

Fig.46 Cyclic Monotonic Stress-Strain Curve 31

Fig.47 S-N 32

Fig.48 33

Fig.49 33

- VII -

Fig.50 S-N 34

Fig.51 S-N 34

Fig.52 AC4C-T6 35

- VIII -

Table 1 LNG 3

Table 2 AC4C-T6 7

Table 3 BISO 18

Table 4 BKIN 20

Table 5 NLISO 21

Table 6 Chaboche 23

Table 7 Conbined 24

Table 8 25

Table 9 AC4C-T6 27

Table 10 27

Table 11 AC4C-T6

29

Table 12 AC4C-T6

31

Table 13 32

Table 14 34

1.

- 1 -

1.

1.1.

LNG -163 LNG (Loading)/

(Unloading) / .

LNG LNG

LNG /// . (Fig. 1, Fig. 2).

Fig. 1 LNG

Fig. 2 LNG Pump

(Fig. 3, 4) LNG

. 2 LNG Pump tower

LNG Pump .

LNG 1 45 (Cargo Hold)

2 LNG cargo Pump ,

LNG 1 810 LNG Cargo pump .

LNG Cargo Pump 80,000

6,600Volt

1.

- 2 -

1,800~2,000m 3/hour LNG

.

Fig. 3 LNG

Fig. 4 LNG

1.2.

(Fig. 5) LNG pump

. LNG cargo pump

LNG Storage Tank, LNG-FPSO, LGNG-RV

LNG .

1.

- 3 -

Fig. 5 LNG LNG

LNG ,

, (Table 1). LNG

, LNG Pump

.

Table 1 LNG (: ,

,

2006)

1.

- 4 -

LNG LNG FPSO, LNG RV

(Fig. 6). LNG 90%

, 30

. LNG

Pump Ebara J.C. Carter , Hitach, Sulzer

LNG

.

Fig. 6 LNG

, 300units LNG LNG cargo pump

, 3

.

LNG Pump

LNG LNG pump

LNG

600 .

1.

- 5 -

1.3.

1.3.1.

submerged ,

. LNG

Pump

.

.

LNG Valve

LNG (KC-1) LNG

.

1.3.2.

LNG Pump J.C.Carter, Shinko, Ebara,

Nikkiso, Hitachi, Cryostar, Eaco, David Brown, Byron-Jackson,

Sulzer Guinard . LNG

LNP Pump

, , . J.C. Carter

Ebara

.

1.4.

LNG Pump

LNG Pump ,

. , , ,

LNG Pump

1.

- 6 -

. ,

, LNG Pump

.

2.

- 7 -

2.

2.1.

2.1.1.

AC4C-T6

, , , ,

, , ,

. AC4C-T6 [1]. (Table 2)

Table 2 AC4C-T6

AC4C

Cu Si Mg Zn Fe Mn

0.25 6.5~7.5 0.20~0.45 0.35 0.55 0.35

Ni Ti Pb Sn Cr Al

0.1 0.2 0.1 0.05 0.1

2.1.2.

l UTM (Universal Testing Machine)

500kN MTS

UTM , , .

Fig. 7 Universal Testing Machine

2.

- 8 -

l Extensometer

Gage length 50mm MTS

.

l Cryogenic Chamber

PID

. -190~+100

(LN) .

Fig. 8 Cryogenic Chamber

2.2. Monotonic Tensile Test

material properties

Monotonic Tensile Test .

Fig. 9 AC4C-T6 (unit : mm)

2.

- 9 -

-

. -

. speed of

testing 0.05kN/s . Fig.8 gage length 50mm

MTS extensometer

UTM Load Cell

.

-

. - 0.2% Offset

method . ASTM

E 8M-00 [2].

Monotonic Tensile Test (-165)

.

Fig. 10 0.2% offset method

2.

- 10 -

Fig. 11 AC4C-T6 Monotonic Tensile Test

Fig. 12 AC4C-T6 Monotonic Tensile Test

2.3. Cyclic Stress-Strain Test

Incremental step test -

.

[7]. block 10. half

2.

- 11 -

block 20 cycle . 0.5%

. cycle 10sec .

ASTM E606-92[1] . Incremental

Step Test .

Fig. 13 Incremental Step Test

2.3.1.

- - -

.

power law function .

( ) '' npK es = (1)

s =

pe =

'K =

'n =

2.

- 12 -

.

'/1

'

n

pK

=

se

(1)

. [4]

'

'

n

KE

+=

sse

(3)

K'

10.002

n'

Log S

cale

Log Scalep

Fig.14 Log-log plot of true cyclic stress versus true cyclic

plastic strain.

2.4. Cyclic Stress-Fatigue Life Test

(S) (N) log-log

S-N .

Fig. 15 S-N [3]

(DNV CN30.7 Fatigue Assessment of ship structure)

2.

- 13 -

Low Cycle Fatigue(LCF) region, High

cycle Fatigue(HCF) region Fatigue limit region

. 104cycle

LCF, 104 cycle HCF .

High Cycle Fatigue , -1

. Monotonic Tensile Test

Cyclic Stress .

3.

- 14 -

3.

LNG Cargo Pump AC4C-T6