Improved method for demagnetisation of naval vessels and Preisach analysis
-
Upload
hayes-nguyen -
Category
Documents
-
view
19 -
download
2
description
Transcript of Improved method for demagnetisation of naval vessels and Preisach analysis
![Page 1: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/1.jpg)
Improved method for demagnetisation of naval
vessels and Preisach analysis
T. M. Baynes, G. J. Russell and A. BaileyUniversity of New South Wales, Sydney AustraliaMaritime Operations Division D.S.T.O. Australia
![Page 2: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/2.jpg)
-1
0
1
-2000 -1000 0 1000 2000H (A/m)
M/Ms
major hysteresisloop
anhysteretic
initial curve
Demagnetisation
(from Chikazumi 1967)
Anhysteretic magnetisation
![Page 3: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/3.jpg)
X Coil
Z Coil
![Page 4: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/4.jpg)
![Page 5: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/5.jpg)
3 Stage Deperm
-2000
-1000
0
1000
2000
0 150 300 450
Time (mins)
Ap
plied
Fie
ld (
A/m
) Stage 1 Stage 2 Stage 3
3 Stage Deperm
-2000
-1000
0
1000
2000
0 150 300 450
Time (mins)
Ap
plied
Fie
ld (
A/m
) Stage 1 Stage 2
3 Stage Deperm
-2000
-1000
0
1000
2000
0 150 300 450
Time (mins)
Ap
plied
Fie
ld (
A/m
) Stage 1
![Page 6: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/6.jpg)
Deperm on Submarine
-1
0
1
0 35 70
Shot Number
Longitudin
al M
-1.5
0
1.5
Vert
ical M
submarine long.submarine vert.
-1
0
1
0 35 70
Shot Number
Longitudin
al M
submarine long.
![Page 7: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/7.jpg)
Problems with Flash D
1.Redundancy
2.Time consuming
3.Predicting deperm outcome
Anhsyteretic Deperm
-2000
-1000
0
1000
2000
0 450
Time
Ap
plied
Fie
ld
(A/m
)
![Page 8: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/8.jpg)
![Page 9: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/9.jpg)
Longitudinal magnetisation during deperm
-1
0
1
0 35 70
Shot Number
M lo
ngitudin
al
submarine long.tube long.
-1
0
1
0 35 70
Shot Number
Longitudin
al M
submarine long.
![Page 10: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/10.jpg)
0
0.001
-10000 -5000 0 5000 10000Deviation from average final LM (A/m)
Norm
ali
sed
fin
al
LM
data
200 A/m100 A/m40 A/m25 A/m3 Stage
0
0.001
-10000 -5000 0 5000 10000Deviation from average final LM (A/m)
Norm
ali
sed
fin
al
LM
data
200 A/m100 A/m40 A/m25 A/m
Final LM
012345
0 50 100Number of Steps
(
kA
/m)
Final VM
0
50
100
150
200
250
0 50 100Number of Steps
(
A/m
)
Distribution of Results
0
0.01
-400 -200 0 200 400Deviation from average VM (A/m)
No
rmalised
data
fo
r fi
nal V
M
200 A/m Steps100 A/m Steps40 A/m steps25 A/m3 Stage Deperm
Anhysteretic deperm results
![Page 11: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/11.jpg)
Preisach Model
![Page 12: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/12.jpg)
![Page 13: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/13.jpg)
-1
0
1
-1 0 1
H/Hmax
M/M
max
bn
bn+1
bn+2
![Page 14: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/14.jpg)
![Page 15: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/15.jpg)
MR (H1 , H2 ) = f(-H1 ).f(H2 )
MR initial(H) =1/2 f(H) 2
![Page 16: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/16.jpg)
0
10
20
30
40
50
60
0 500 1000 1500 2000 2500H (A/m)
MR (
kA
/m)
Stage 1 data approximation
0
10
20
30
40
50
60
0 500 1000 1500 2000 2500H (A/m)
MR (
kA/m
)
Initial R emanent M C urve
0
10
20
30
40
50
60
0 500 1000 1500 2000 2500H (A/m)
MR (
kA/m
)
Initial R emanent M C urveAnhysteretic deperm on tube
-1.2
-0.8
-0.4
0
0.4
0.8
1.2
0 5 10 15 20 25
Shot number
M/M
sta
rttheorytube
Stage 1 Data for submarine
-1.2
-0.8
-0.4
0
0.4
0.8
1.2
0 5 10 15
Shot number
M /
Msta
rtsubmarinetheory
![Page 17: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/17.jpg)
Remanent VM after anhysteretic deperm
0
3000
0 200 400 600 800
Vertical Bias Field (A/m)
Rem
an
en
t V
M
(A/m
)
![Page 18: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/18.jpg)
Conclusions:• laboratory simulation allows experiments into
alternative deperm procedures.• Anhysteretic deperm produces more reliable
vertical magnetisation AND allows for theoretical modelling. Flash D can not be modelled easily.
• Preisach model used to describe bulk magnetisation changes in tube.
• It’s possible to use just use the initial remanent magnetisation curve to predict deperm results.
• Stage 1 data from previous deperms on submarines can be used as approximation for initial curve – can also predict deperm results.
![Page 19: Improved method for demagnetisation of naval vessels and Preisach analysis](https://reader035.fdocuments.net/reader035/viewer/2022062422/56812d99550346895d92b5bc/html5/thumbnails/19.jpg)
-10000
-5000
0
5000
10000
15000
-1 0 1x (m)
M (nT)
tube alone
-10000
-5000
0
5000
10000
15000
-1 0 1x (m)
M (nT)
tube alone
-10000
-5000
0
5000
10000
15000
-1 0 1x (m)
M (nT)
block alone
-10000
-5000
0
5000
10000
15000
-1 -0.5 0 0.5 1x (m)
M (nT)
combined
-10000
-5000
0
5000
10000
15000
-1 0 1x (m)
M (nT)
block alone
-10000
-5000
0
5000
10000
15000
-1 -0.5 0 0.5 1x (m)
M (nT)
combined