TPT May 2010

A rticle

Figure 20 : Comparison of experimental and FEM studies with batdorf parameters

Figure 17 : Three wave mode of model A4 in FEM study

Conclusions Important results of this paper include: 1. Buckling pressure of pipeline is increased with a decrease of ring spacing. 2. Buckling strength of pipeline is related to the number of waves made-up on specimens. 3. Thickness of rings has no great effect on buckling pressure against value of used steel in specimens. 4. Using of ring stiffeners has economical benefits over same weight specimens without rings. 5. Geometric properties of specimens such as length or rings spacing or diameter of specimens has considerable effects on buckling behaviour of specimens. 6. There is good corresponding data between experimental and FEM results according to comparison of buckling pressure and circumferential modes of specimens. References [1] BS 8010, 1993, Code of practice for pipelines - part 3 pipelines subsea: Design, Construction and Installation, British Standards Institution, UK. [2] API RP1111, 1999, Design, Construction, Operation, and Mainrenance of Offshore Hydrocarbon Pipelines (Limit state design), American Petroleum Institute, Washington, DC. [3] ABS, 2005, Guide for building and classing subsea pipeline systems and risers, American Bureau of Shipping, Houston. [4] DNV Submarine pipelines system, 2000, OS-F101, Det Norske Veritas, Norway. [5] Mesloh, R. Johns, T. G., and Sorenson, J. E. 1976, "The propagation buckle." BOSS' 76, Vol. 1, pp.787-797. [6] Kyriakides, S., & Babcock, C. D., 1981, "Experimental determination of the propagation pressure of circular pipes" ASME Journal of Pressure Vessel technology, Vol. 103, pp. 328-336. [7] Kamalarasa, S. and Calladine, CR. 1988, "Buckle propagation in submarine pipelines." International Journal of Mechanical Science, Vol. 30, No.3. 4, pp 0217- 228. [8] Murray, D. W., & Zhilong Zhou., 1995, "Analysis of potbuckling behaviour of line pipe subjected to combine loads" International Journal of Solids Structures, Vol. 32, No. 20, pp. 3015-3036. [9] Pasqualino, I. P., & Estefen, S. F., 2001, "A nonlinear analysis of the buckle propagation problem in deepwater pipelines" International Journal of Solids and Structures, Vol. 38, pp. 8481-8502. [10] Netto, T. A., & Kyriakides, S., 2000, "Dynamic performance of integral buckle arrestors for offshore pipelines. Part I Experiments" International journal of Science, Vol. 42, No. 7, pp. 1045-1043. [11] Kyriakides, S. & Netto, T. A., 2000, "On the dynamics of propagating buckle in pipelines," International Journal of Solids and Structures, Vol. 3, pp. 6843-6867.

Figure 18 : Three wave mode of specimen A0 in experimental study

Figure 19 : Three wave mode of model A0 in FEM study

Maximum experimental mode number

Specimen label

FEM mode number

A0 A4 A7

2 3 3 5

2 3 4

A13 5 Table 5 : Comparison of mode number between experimental and FEM studies

Comparison with batdorf parameters Figure 20 shows experimental and FEM comparison with batdorf parameters. This curve indicates that FEM and experimental results correspond well together. But there are few differences between these results with batdorf parameters. This is because specimens were considered in ideal condition such as long length or sections without imperfections and too elastic a behaviour was considered for them. In this graph X and Y direction were considered, and respectively. Which .

H Showkati – Civil Eng. Department, Urmia University, Iran R Shahandeh – Civil Eng. Department, Sama organization (affiliated with Islamic Azad university), Khoy branch, Khoy, Iran

110

M ay 2010

www.read-tpt.com

›