2009W ENGI 8673 L11 Prop Buckspkenny/Courses/Undergraduate/ENGI8673/... · 2009. 2. 10. · © 2009 S. Kenny, Ph.D., P.Eng. ENGI 8673 Subsea Pipeline Engineering – Lecture 11 Alternative

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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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.


1MPa (10 bar) per 100 m water depth


Gulf of Mexico (cont.)

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Worldwide Deepwater Basins

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Scotian Shelf

Gulf of Mexico

Australia Brazil West Africa

North Sea

Asia

Newfoundland

Norwegian Sea


 Local Offshore   Orphan Basin

  2200m   Flemish Pass

  1100m   Salar Basin

  1500m


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)


Practical Considerations  Fabrication

  Ovalization   Wall thickness

variation   Nonuniform material

properties   Residual stress

 Mechanics   Hoop stress   Bending stress

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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


System Collapse External Overpressure

 Sec.5 D400   Characteristic

Resistance for Collapse   Function of 3

components   Elastic   Circumferential

yield   Ovality

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Geometry and Material Parameters  Wall Thickness Definition

 Fabrication Processes

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Solution to Equation 5.10  Sec.13 E700

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Pressure Collapse Design Check  Sec.5 D402

  Allowable hydrostatic pressure

  Local weakness

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Propagation Buckling  Trigger

  Local buckle or mechanism

 Driving Force   Propagation pressure

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Ref: DANotes (2006)


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)


C-FER Test Facility Ref: DeGeer et al. (2007) Ref: DeGeer et al. (2004)


Ref: DeGeer et al. (2004)


Flattening Cross-Over Mechanism

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Ref: Luciano et al., (2006)


Flipping Cross-Over Mechanism

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Ref: Luciano et al., (2006)


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


Buckle Arrestor Design  Sec.5 D502

  Linepipe   geometry   Arrestor

geometry   Arrestor

length

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Buckle Arrestor Optimization

 Spacing  Cost  Risk  Spares Philosophy

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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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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


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


Pipeline Route


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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2009W ENGI 8673 L11 Prop Buckspkenny/Courses/Undergraduate/ENGI8673/... · 2009. 2. 10. · © 2009 S. Kenny, Ph.D., P.Eng. ENGI 8673 Subsea Pipeline Engineering – Lecture 11 Alternative

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