contact us     
Buckling Modes of Multilayer Pipeline Materials  

Thread by Nick Higham on 23 Jul 2009 at 17:19:06 

Hi,

My questions concern a chemical-physical explanation of buckling and failures modes of multilayer pipeline materials, in which the susbequent materials are glued or non glued (in that case an annular space exists) and may consist of different sort of materials, say a polymer, PE or PVDF and a metallic material, think of stainless steel or aluminum. Now apart from all the finite element stuff that is currently available (Abaqus, Ansys, MSC Marc, Comsol, SolidWorks) a fundamental picture seems hard to define. My point is: buckling or the potential buckling of multilayer materials in a circumferential configuration caused by:

1) Hoop stresses in the materials as a result of hydrostatic pressure, as each material builds up compression and tension stresses, and expands in line according to their invidiviudal properties.

2) Temperature / thermal stresses in the materials and/or swelling stresses on the interface or as an indirect result elsewhere in the polymer or metal.

3) Swelling stress / thermal expansion by diffused / solved chemicals, especially at high pressures and high temperatures. One might think of gas, say CO2 or Potable Water transport at high pressures -giving rise to substantial volumetric expansion (perhaps also moisture induced).

Or is it a combination of the thee factors; then how do they combine and what are the appropriate formulae to describe these phenomena?

Thanks,
Nick Higham

Note: really appreciate this integrated approach expert log on Composite Agency.com.


    Comment by Holger on 24 Jul 2009 at 08:43:47  | |responses: 0|
    Nick, maybe the following is helpful:

    Titre du document / Document title:
    Horizontal cylinder-in-cylinder buckling under compression and torsion : Review and application to composite drill pipe

    Auteur(s) / Author(s):
    WICKS Nathan ; WARDLE Brian L. ; PAFITIS Demos ;

    Résumé / Abstract:

    Available analytical results and experiments on the structural behavior of constrained horizontal cylinders subjected to axial compression, torsion, and gravitational loads are reviewed. Such configurations are of interest to the oil-drilling field and provide static design expressions for steel tubulars. The buckling problem is similar to restrained railroad tracks and submerged/underwater pipelines under thermal expansion. Due to outer cylinder constraint and gravitational loads, analysis has shown that long cylinders initiate buckling at loads significantly higher than classical Euler buckling loads. For these constrained long cylinders, buckling initiates in a sinusoidal mode that snakes along the lower surface of the constraining cylinder. Classic analytical expressions hold that as the axial load increases, the cylinder achieves an overall helically buckled state in which the buckled cylinder forms a helix spiraling around the inner surface of the constraining cylinder. Torsion is shown to have little effect on either buckling load but controls the sense/direction of the helical buckling. Little experimental data exist on constrained cylinder buckling, and it is unclear how the initiating sinusoidal mode transitions to the helical mode. Implications of the buckling progression for composite cylinder applications are described including the finding that composites perform poorly relative to steel on the metric of buckling due to lower density and axial stiffness; composites perform well on the metric of lock-up length when friction is considered. Based on this review and findings for composite cylinders, recommendations are made for further work.

    Revue / Journal Title:
    International journal of mechanical sciences ISSN 0020-7403 CODEN IMSCAW
    Source / Source:
    2008, vol. 50, no3, pp. 538-549 [12 page(s) (article)]
    Langue / Language
    Anglais

    Editeur / Publisher
    Elsevier, Oxford, ROYAUME-UNI (1960) (Revue)

    Mots-clés d'auteur / Author Keywords
    Helical buckling ; Sinusoidal buckling ; Cylinder ; Oil drilling ; Compression ; Torsion ;
    Localisation / Location
    INIST-CNRS, Cote INIST : 1321, 35400017369068.0150
     |   disclaimer