Our site uses cookies necessary for its proper functioning. To improve your experience, other cookies may be used: you can choose to disable them. This can be changed at any time via the Cookies link at the bottom of the page.

Morphological and Structural Effects on Slow Crack Growth in PE-Pipes [PE]


Additional Information - Posters

Plastic Pipes Conference Association # 2006 Washington DC

Kratochvilla, Muschik, Dragam

Slow crack growth (SCG) was measured by means of an adaptive to the Full Notch Creep Test (FNCT) : the 2-Notch Creep Test (2NCT). This notching geometry offers the advantage, that the sensitive zones of samples made of pipe specimens are conserved : the inner- and outer-pipe wall layers. This test geometry makes it possible to achieve fracture results including the sensitive regions with the highest internal-stresses and orientations. Fracture results on a DN 315x17,9 PE100 pipe of a bimodal PE100 compound show, that the outer-pipe wall specimens have the shortest times to failure. To the inner-pipe wall section the failure times increase. As reference a 6 mm thick compression moulded sheet with slow cooling rate was produced of the same material. Samples of the sheet show the highest failure time. The different failure times can be related to morphological- and structural-effects but furthermore investigations are necessary. It was shown in samples investigated prior total fracture that there is a complex fracture behaviour evident in pipe specimens due to morphological- and structural-effects with partial secondary crackinitiation points, which leads to the different failure times of the pipe wall sections.

Please note that the whole article content is available on PPCA website only :

Related papers


Author(s) : Thomas R. Kratochvilla, Patrick Grünbeck, Christoph Bruckner, Raimund Eremiasch, Harald Wilhelm, Mario Vukelja

In the last decades pipe dimensions of extruded PE pipes have reached new orders of size. Today, PE pipes with outer diameters of up to DN/OD 3500 mm are produced and used for pressure pipe applications like seawater intake/discharge, outfall, sewage and industrial process piping systems. To test the long-term...


Author(s) : Hermann van Laak, Jan Heimink, Mario Messiha, Andreas Frank, Christoph Bruckner, Thomas Kratochvilla

For high pressure pipes above maximum operation pressure of 10 bar, this paper emphasizes PA-U12 as the easy to install alternative to steel. It underlines the superb performance of PA-U12 pipes for alternative installation techniques without need for a separate mechanical protection. An unplasticized polyamide 12...

2018 Las-Vegas : Accelerated pipe test methods to evaluate PE 100-RC materials - Possibilities for iso standardisation

Author(s) : Thomas R. Kratochvilla, Raimund Eremiasch, Christoph Bruckner

In the last years effort has been made to develop and standardise new accelerated test methods to evaluate PE 100-RC materials in short times in form of test bars. The two most important developments, the cracked round bar test (CRB test) and the strain hardening test (SH test) were published as final ISO standards in...

2012 Barcelona : Accelerated material testing with cyclic CRB tests

Author(s) : Andreas Frank, Anita Redhead, Thomas Kratochvilla, Heinz Dragaun, Gerald Pinter

Key words : Polyethylene, pipe, test method, lifetime, slow crack growth For a qualitative characterization of the slow crack growth resistance of polyethylene pipe grades several test methods are available. Especially for modern pipe grades these test methods exceed practical time frames and new acceleration methods...

2010 Vancouver : Comparison of novel testing methods for determination of slow crack growth in PE 100

Author(s) : Christian Tischler, Markus Haager, Thomas R. Kratochvilla, Heinz Muschik, Heinz Dragaun

The static test method of the Notched Ring Test (NRT) is compared with a fatigue testing method of Cracked Round Bar (CRB). Both methods are candidates for the classification of polyethylene (PE) materials with high resistance against Slow Crack Growth (SCG). In this paper tests of two PE 100 and two PE 100-RC...

Influence of Local Gelation Degree on the Frequency of Breaks of PVC Pressure Pipes

Author(s) : Muschik, Dragaun, Valenta

Static Loading Methods without Wetting Agents for Determination of Slow Crack Growth in PE 100

Author(s) : Tischler, Kratochvilla, Muschik, Dragaun

Processing of Polypropylene Pressure Pipes

Author(s) : Muschik, Detter

Members of the Association

BOREALISBOROUGEFormosa Plastics CorporationHanwha TotalEnergiesINEOS O&PIRPCKorea Petrochemical IND. Co., LTD (KPIC)LyondellBasellORLEN UnipetrolPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE