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.
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...
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...
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...
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...
Author(s) : Muschik, Dragaun, Valenta
Author(s) : Tischler, Kratochvilla, Muschik, Dragaun
Author(s) : Muschik, Detter
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