The Effect of Polymer Pipe Weld Geometry on Creep Lifetime


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In the case of large diameter polyethylene (PE) and polypropylene (PP) pipes the most usual joint is the butt weld. This paper focuses on the influence of a weld bead on the service life of welded pipes from a fracture mechanics perspective. To this aim the stress concentrator created by the connection between the weld bead and the pipe’s free surface is modelled as a notch. Global parameters defining properties of stress and strain field in the notch region are calculated for materials with a prevailing Norton-type creep. It is demonstrated that in the case of creep loading conditions and ductile failure mode the existence of such stress concentrators has no negative influence on the lifetime of pipes.



Edited by:

Pavel Šandera




M. Ševčík et al., "The Effect of Polymer Pipe Weld Geometry on Creep Lifetime", Key Engineering Materials, Vol. 465, pp. 175-178, 2011

Online since:

January 2011




[1] L.E. Janson, Plastics Pipes for Water Supply and Sewage Disposal, Borealis, Stockholm, (1999).

[2] M. Ševčík, P. Hutař, L. Náhlík, Z. Knésl., A Functionally Graded Material Model of Cracked Polymer Weld, in Computational Modelling and Advanced Simulations 2009, June 30 - July 3 Bratislava, (2009).

[3] Pilkey, Walter D: Peterson´s Stress Concentration Factors, John Wiley, 2nd edition, (1997).

[4] Knésl, Z., Preclík P., Radon, J.C., Two parameter characterization of notched specimen under creep, Metallic Materials 41, 84-96, (2003).

[5] Hamouda, H., Fracture mechanics global approach concepts applied to creep slow crack growth in a medium density polyethylene (MDPE), Engineering Fracture Mechanics 74, 2187-2204, (2007).