Shawn Kenny, Ph.D., P.Eng. Assistant Professor Faculty of Engineering and Applied Science Memorial University of Newfoundland [email protected]
Lecture 11 – Mechanical Design: Propagation Buckling
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Lecture Goals
Students will be able to: calculate the system collapse (external
overpressure only) and propagation buckling requirements for subsea pipelines in accordance with DNV OS-F101
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ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Reading List
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# Document
11.1 DNV OS-F101 Submarine Pipeline Systems. Offshore Standard, 240p. Section 5 D300, D400 & D500
11.2 Chaudhuri, J and Nash, I. (2005). “Medgaz: the ultra-deep pipeline”, Pipeline World, June, 10p.
11.3 Langner, C. (1999). “Buckle arrestors for deepwater pipelines.” OTC, Paper OTC 10711, 12p.
11.4 Luciano, O. Mantovano, L.O., Amenta, P., Charreau, R.. Johnson, D., Assanelli, A. and Toscano, R.G. (2006). Finite Element Modelling and Experimental Validation of Buckle Arrestors for Deepwater Pipelines., Mecánica Computacional Vol XXV, pp.687-704.
11.5 DeGeer, D., Marewski, Hillenbrand, H-G, Weber, B. and Crawford, M. (2004). “Collapse testing of thermally treated line pipe for ultra-deepwater applications.” Proc., 4th Pipeline Technology Conference, 11p.
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
1MPa (10 bar) per 100 m water depth
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Gulf of Mexico (cont.)
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ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Worldwide Deepwater Basins
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Scotian Shelf
Gulf of Mexico
Australia Brazil West Africa
North Sea
Asia
Newfoundland
Norwegian Sea
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Local Offshore Orphan Basin
2200m Flemish Pass
1100m Salar Basin
1500m
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Elastic Collapse Pressure Theory of Elastic
Stability Onset of unbounded
instability Idealization of
perfect cylinder Does this
represent reality?
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Ref: Timoshenko and Gere (1961)
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Practical Considerations Fabrication
Ovalization Wall thickness
variation Nonuniform material
properties Residual stress
Mechanics Hoop stress Bending stress
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ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Alternative Critical Collapse Pressure
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Ref: Timoshenko and Gere (1961)
Pc ≡ Critical collapse pressure m ≡ Mean radius to nominal wall thickness ratio n ≡ Imperfection amplitude to nominal wall thickness ratio SMYS/m ≡ Pressure to yield perfect cylinder
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
System Collapse External Overpressure
Sec.5 D400 Characteristic
Resistance for Collapse Function of 3
components Elastic Circumferential
yield Ovality
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ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Geometry and Material Parameters Wall Thickness Definition
Fabrication Processes
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ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Solution to Equation 5.10 Sec.13 E700
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ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Pressure Collapse Design Check Sec.5 D402
Allowable hydrostatic pressure
Local weakness
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ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Propagation Buckling Trigger
Local buckle or mechanism
Driving Force Propagation pressure
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Ref: DANotes (2006)
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Buckle Arrestor Mitigation Technique
Grouted sleeve
Collar or integral ring
Linepipe joint
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Ref: Langner, (1999)
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng. 17
Ref: Rigzone (2008)
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng. 18
C-FER Test Facility Ref: DeGeer et al. (2007) Ref: DeGeer et al. (2004)
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng. 19
Ref: DeGeer et al. (2004)
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Flattening Cross-Over Mechanism
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Ref: Luciano et al., (2006)
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Flipping Cross-Over Mechanism
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Ref: Luciano et al., (2006)
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Buckle Arrestor Criteria Sec.5 D500
External pressure, pe
Collapse pressure, pc
Initiation pressure, pinit
Propagating pressure, ppr
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pc > pinit > pprLocal section collapse or buckle required before propagation can be initiated
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Buckle Arrestor Design Sec.5 D502
Linepipe geometry Arrestor
geometry Arrestor
length
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ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Buckle Arrestor Optimization
Spacing Cost Risk Spares Philosophy
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ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Example 11-01 Calculate the allowable external pressure for
collapse and allowable external pressure for propagation buckling across D/t ratios of 20, 25, 30, 35 and 45. To analyze the load effects, use t1 in all calculations, which will be a conservative estimate. The pipeline diameter is 762 mm and the linepipe grade is DNV SAW 450. The initial ovality is fo = 0.01. The seawater density is 1025kg/m3. The partial factors include αfab = 0.85, γsc = 1.04, and γm = 1.15.
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ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Example 11-01
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0
10
20
30
40
50
60
20 25 30 35 40 45
Pre
ss
ure
(M
Pa
)
D/t1
Elastic Pressure
Plastic Collapse
Pressure
Characteristic Collapse
Pressure
Allowable External
Collapse Pressure
Propagating Pressure
Allowable External
Propagating Pressure
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
Example 11-01
Z is the water depth
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D/t1 Pel
[5.11] Pp
[5.12] b
[13.13] c
[13.13] d
[13.13] u
[13.13] v
[13.13] Φ
[13.13] y
[13.13] Pc
[13.13]
Collapse Pe
[5.14]
Collapse z
[5.14]
Ppr [5.16]
Propagation Pe [5.15]
No BA z [5.15]
(MPa) (MPa) (MPa) (MPa2) (MPa3) (MPa2) (MPa3) (rad) (MPa) (MPa) (MPa) (m) (MPa) (MPa) (m) 20 56.3 38.3 -56.3 -1894 82398 -984 16806 2.15 11.97 30.7 25.7 2556 7.5 6.3 622 25 28.8 30.6 -28.8 -1157 27000 -478 7052 2.31 10.69 20.3 17.0 1688 4.3 3.6 356 30 16.7 25.5 -16.7 -778 10851 -290 3090 2.25 7.60 13.2 11.0 1095 2.7 2.3 226 35 10.5 21.9 -10.5 -558 5020 -198 1490 2.13 5.25 8.8 7.3 728 1.8 1.5 154 40 7.0 19.1 -7.0 -420 2575 -145 782 2.03 3.70 6.0 5.1 503 1.3 1.1 110 45 4.9 17.0 -4.9 -327 1429 -112 441 1.95 2.69 4.3 3.6 361 1.0 0.8 82
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng. 28
Pipeline Route
ENGI 8673 Subsea Pipeline Engineering – Lecture 11 © 2009 S. Kenny, Ph.D., P.Eng.
References DANotes (2006). http://www.mech.uwa.edu.au/DANotes/buckling/
mechanisms/mechanisms.html DeGeer, D., Marewski, U., Hillenbrand, H-G., Weber, B. and Crawford, M.
(2004). Studies on Collapse Testing of UOE Linepipe for Deepwater Applications., Proc., Pipeline Technology, p.753-771.
DeGeer, D., Timms, C., Wolodko, J., Yarmuch, M., Preston, R. and MacKinnon, D. (2007). Local Buckling Assessments for the Medgaz Pipeline. Proc., OMAE 2007, OMAE2007-29493, 11p.
DNV (2007). Submarine Pipeline Systems. Offshore Standard, DNV OS-F101, October 2007, 240p.
Luciano, O. Mantovano, L.O., Amenta, P., Charreau, R.. Johnson, D., Assanelli, A. and Toscano, R.G. (2006). Finite Element Modelling and Experimental Validation of Buckle Arrestors for Deepwater Pipelines., Mecánica Computacional Vol XXV, pp.687-704.
Rigzone (2008). http://www.rigzone.com/news/article.asp?a_id=5222 Timoshenko, S.P. and Gere, J.M. (1961). Theory of Elastic Stability.
McGraw-Hill.
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