Experimental investigations on the fatigue resistance of ... · Experimental investigations on the fatigue resistance of automatically welded tubular X-joints for jacket support structures.
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Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Geometrical Dimensions
Scaled tubular X-joint Scaling 1:3.3
S355 J2 + Z 35
β= = 0.6
τ= = 0.44
dBraceDChord
tBraceTChord
4
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Weld Seam Preparation
5
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Automatically Welding Procedure
S… Start ofWelding
E… End ofWelding
6
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Laser Scanning of Weld Geometry
Scanning of weld geometry utilizing a blue line laser Input for numerical analysis
040 2060 -60-40-20
0
20
40
60
80
z [m
m]
y [mm]
Weld SeamGroove
Saddle position (270°)
7
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
6020 400 120100800
20
40
60
80
z [m
m]
y [mm]
Saddle position (270°)
8
Comparing weld geometry of 28 tubular X-joints
Reproducibility of Weld Geometry
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Reproducibility of Weld Geometry
6020 400 120100800
20
40
60
80
z [m
m]
y [mm]
Saddle position (270°)
8
Δmax ≈ 0.8 mm
Δnotch ≈ 0.2 mm
Comparing weld geometry of 28 tubular X-joints Good reproducibility is given
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Test Setup of Axial Fatigue Tests
High cycle fatigue range;R = 0.1; f = 5 Hz
9
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Test Setup of Axial Fatigue Tests
High cycle fatigue range;R = 0.1; f = 5 Hz Through thickness crack Loss of over/under pressure
Pres
sure
[bar
] 0
-0.2
Pressure
Loss of pressure
-0.4-0.6-0.8-1.0
Number of Cycles [-]1 2 3 4
x105
10
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Test Setup of Axial Fatigue Tests
1 mm
11
High cycle fatigue range;R = 0.1; f = 5 Hz Through thickness crack Loss of over/under pressure Optical digitization of
damage development
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Fatigue Damage Digitization
Saddle
SaddleBrace
Weld
Chord y
xεx [%]
0.0 4.0 8.0
Digital image correlation measurement of fatigue damage development 3D surface model of hot spot
for unloaded X-joint Axial fatigue test with ΔσN = 41.3 MPa
N = 0 Cycles
12
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Fatigue Damage Digitization
Brace
Weld
Chord
Saddle
13
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
SaddleBrace
Weld
Chord y
xεx [%]
0.0 4.0 8.0
Fatigue Damage Development
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 x106
Number of Cycles [-]
Dis
plac
emen
t[m
m]
0.2
0.4
0.6
14
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Brace
Weld
Chord y
xεx [%]
0.0 4.0 8.0
First Visible Crack
Saddle
Fatigue Damage Development
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 x106
Number of Cycles [-]
Dis
plac
emen
t[m
m]
0.2
0.4
0.6
15
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Fatigue Damage Development
Brace
Weld
Chord y
x
εx [%]0.0 4.0 8.0
Saddle
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 x106
Number of Cycles [-]
Dis
plac
emen
t[m
m]
0.2
0.4
0.6
16
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Fatigue Damage Development
Saddle
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 x106
Number of Cycles [-]
Dis
plac
emen
t[m
m]
0.2
0.4
0.6
17
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
F
F
S-N Curve acc. to EC3 Background Doc.
18
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
F
F
Increased S-N curve (FAT 126, m=3) for automatically welded X-joints
S-N Curve acc. to EC3 Background Doc.
18
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
F
F
S-N Curve acc. to EC3 Background Doc.
19
Increased S-N curve (FAT 126, m=3) for automatically welded X-joints
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
F
F
S-N Curve acc. to EC3 Background Doc.
20
Increased S-N curve (FAT 126, m=3) for automatically welded X-joints
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
Summary and Outlook
Fatigue resistance of automatically welded tubular X-joints 32 fatigue tests on single- and double-sided
automatically welded X-joints Increased S-N curve (FAT126) for
the robot welded tubular X-joints Monitoring of damage/crack
development utilizing DIC possible
Improving the automatically welding procedure
21
Karsten Schürmann – Experimental investigations on the fatigue resistance of automatically welded tubular X-joints
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The IGF project 19104 N of the FOSTA was supported via AiFwithin the programme for promoting the Industrial Collective Research (IGF) of the German Ministry of Economic Affairs and Energy (BMWi), based on a resolution of the German Parliament.