Skip to main content

Research Repository

Advanced Search

Structure, processing and performance of ultra-high molecular weight polyethylene (IUPAC Technical Report). Part 4: sporadic fatigue crack propagation

Bucknall, Clive; Altstädt, Volker; Auhl, Dietmar; Buckley, Paul; Dijkstra, Dirk; Galeski, Andrzej; Gögelein, Christoph; Handge, Ulrich A.; He, Jiasong; Liu, Chen-Yang; Michler, Goerg; Piorkowska, Ewa; Slouf, Miroslav; Vittorias, Iakovos; Wu, Jun Jie

Structure, processing and performance of ultra-high molecular weight polyethylene (IUPAC Technical Report). Part 4: sporadic fatigue crack propagation Thumbnail


Authors

Clive Bucknall

Volker Altstädt

Dietmar Auhl

Paul Buckley

Dirk Dijkstra

Andrzej Galeski

Christoph Gögelein

Ulrich A. Handge

Jiasong He

Chen-Yang Liu

Goerg Michler

Ewa Piorkowska

Miroslav Slouf

Iakovos Vittorias



Abstract

Fatigue tests were carried out on compression mouldings supplied by a leading polymer manufacturer. They were made from three batches of ultra-high molecular weight polyethylene (UHMWPE) with weight-average relative molar masses, ¯¯¯¯ M W, of about 0.6 × 106, 5 × 106 and 9 × 106. In 10 mm thick compact tension specimens, crack propagation was so erratic that it was impossible to follow standard procedure, where crack-tip stress intensity amplitude, ΔK, is raised incrementally, and the resulting crack propagation rate, da/dN, increases, following the Paris equation, where a is crack length and N is number of cycles. Instead, most of the tests were conducted at fixed high values of ΔK. Typically, da/dN then started at a high level, but decreased irregularly during the test. Micrographs of fracture surfaces showed that crack propagation was sporadic in these specimens. In one test, at ΔK = 2.3 MPa m0.5, there were crack-arrest marks at intervals Δa of about 2 μm, while the number of cycles between individual growth steps increased from 1 to more than 1000 and the fracture surface showed increasing evidence of plastic deformation. It is concluded that sporadic crack propagation was caused by energy-dissipating crazing, which was initiated close to the crack tip under plane strain conditions in mouldings that were not fully consolidated. By contrast, fatigue crack propagation in 4 mm thick specimens followed the Paris equation approximately. The results from all four reports on this project are reviewed, and the possibility of using fatigue testing as a quality assurance procedure for melt-processed UHMWPE is discussed.

Citation

Bucknall, C., Altstädt, V., Auhl, D., Buckley, P., Dijkstra, D., Galeski, A., …Wu, J. J. (2020). Structure, processing and performance of ultra-high molecular weight polyethylene (IUPAC Technical Report). Part 4: sporadic fatigue crack propagation. Pure and Applied Chemistry, 92(9), 1521-1536. https://doi.org/10.1515/pac-2019-0408

Journal Article Type Article
Acceptance Date Mar 20, 2020
Online Publication Date Aug 24, 2020
Publication Date 2020
Deposit Date Dec 9, 2020
Publicly Available Date Dec 9, 2020
Journal Pure and Applied Chemistry
Print ISSN 0033-4545
Electronic ISSN 0033-4545
Publisher International Union of Pure and Applied Chemistry
Peer Reviewed Peer Reviewed
Volume 92
Issue 9
Pages 1521-1536
DOI https://doi.org/10.1515/pac-2019-0408

Files





You might also like



Downloadable Citations