Constraint effect on the slow crack growth in polyethylene

0385514 - ÚFM 2013 RIV GB eng J - Journal Article
Hutař, Pavel - Zouhar, Michal - Nezbedová, E. - Sadílek, J. - Žídek, J. - Náhlík, Luboš - Knésl, Zdeněk
Constraint effect on the slow crack growth in polyethylene.
International Journal of Structural Integrity. Roč. 2, č. 3 (2012), s. 118-126. ISSN 1757-9864
R&D Projects: GA ČR GD106/09/H035; GA ČR GA106/09/0279; GA ČR GC101/09/J027
Institutional support: RVO:68081723
Keywords : slow crack growth * polyethylene * constraint
Subject RIV: JL - Materials Fatigue, Friction Mechanics

From the practical point of view, most relevant damage to high density polyethylene (HDPE) structures is caused by slow crack growth. Therefore, detailed information about this type of damage is necessary. Experimental results transfer from specimens to real structure can be influenced by structure geometry (constraint). Therefore, the purpose of this paper is to investigate and discuss the effect of the constraint and relation between crack mouth opening displacement (CMOD) and crack length. The constraint effect is mainly effect of the structure geometry and can be quantified by T-stress. Two different test specimens with different constraint level (T-stress) were prepared: single edge notched specimen and modified single edge notch (SEN) specimen. The crack mouth opening displacement, crack tip opening displacement and crack length was measured. The main conclusions of this work can be summarized as: the slow crack growth rate in HDPE materials corresponds to velocity of CMOD; the influence of the presented specimen geometry on slow crack growth rate can be considered as negligible; and for transfer of the experimental results from specimens to real structure the influence of the structure geometry (constraint) is not critical.
Permanent Link: http://hdl.handle.net/11104/0215240