Mixed Mode I/III fatigue fracture characterization of Polyoxymethylene

• Published in: International journal of fatigue 2020-01, Vol.130, p.105269, Article 105269
• Main Authors: Gosch, Anja, Berer, Michael, Hutař, Pavel, Slávik, Ondrej, Vojtek, Tomáš, Arbeiter, Florian J., Pinter, Gerald
• Format: Article
• Language: English
• Subjects: Crack propagation; Equivalent stress intensity factor; Fatigue crack growth; Fatigue failure; Fatigue tests; Fracture mechanics; Materials fatigue; Mixed Mode loading; Polymers; Stress intensity factors
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/j.ijfatigue.2019.105269

•Mixed Mode I/III fatigue loading of POM-H ends up in a clearly visible life time reduction compared to pure Mode I loading.•Three equations of equivalent stress intensity factor were presented to determine the characterized Mixed Mode I/III loading.•For low Mode III/Mode I loading ratios wear abrasion and friction were detected on the fracture surfaces of the tested fatigue specimens.•Detailed fracture surface analysis displayed so called “factory roof formations” which are typical for Mixed Mode I/III fatigue loading. The crack growth behaviour of thermoplastic polymers is a relevant topic in current research. While a dominant portion of studies in fracture mechanics investigates Mode I loading situations, very little is done to better understand Mixed Mode crack growth, which can be equally important to accurate live time predictions of polymer parts. In this research, fatigue tests on cylindrically notched specimens were performed in Mixed Mode I/III loading and compared via the so called equivalent stress intensity factor. Under these loading conditions, a significant reduction of the cycles to fracture occurred compared to pure Mode I.