Investigation of the dynamic mechanical behavior of polyetheretherketone (PEEK) in the high stress tensile regime
- 542 Downloads
Due to its outstanding mechanical performance both in static and dynamic loading and its resistance up to very high temperatures, Polyetheretherketone (PEEK) has attracted many practical applications. The loaded contact state for the application of PEEK rolls as bearing elements was recently analyzed by the corresponding author. High irreversible deformations on the mantle side were caused by the rolling contact and thus the rolling performance is supposed to be strongly affected by the dynamic mechanical properties of this irreversibly deformed material. Tensile fatigue tests at various stress levels up to the thermally dominated fatigue regime were conducted in order to get information regarding the dynamic mechanical material behavior at high stress regimes. Two types of PEEK (annealed and untreated) were investigated and two load ratios, R, were used (0.1 and 0.5). During the fatigue tests extensometer strain, load and surface temperature were recorded and a quantitative hysteresis loop analysis with calculated secant modulus and dynamic modulus was performed. Furthermore, the concept of isocyclic stress–strain diagrams was applied to enlarge and confirm the results obtained from the hysteresis loop analysis. A sharp transition between thermally dominated and mechanically dominated fatigue regimes was found for both PEEK types (annealed and untreated) and for both load ratios. Moreover, the annealed PEEK was stiffer in the tensile fatigue tests than the untreated material. Both examined PEEK types showed distinct hardening throughout the fatigue tests which made them “more elastic” (higher stiffness and less damping).
KeywordsPolyetheretherketone (PEEK) Fatigue Isocyclic stress–strain diagrams Hysteresis curves Hysteretic heating
The research work of this paper was performed at the Polymer Competence Center Leoben GmbH (PCCL, Austria) within the framework of the COMET-programme of the Austrian Ministry of Traffic, Innovation and Technology with contributions by the Montanuniversitaet Leoben (Chair of Materials Science and Testing of Plastics). The PCCL is funded by the Austrian Government and the State Governments of Styria and Upper Austria.
- Ferry, J.D.: Viscoelastic Properties of Polymers, 3rd edn. Wiley, New York (1980) Google Scholar
- Hertzberg, R.W., Manson, J.A.: Fatigue of Engineering Plastics. Academic Press, New York (1980) Google Scholar
- Heym, B., Beitz, W.: Zur Belastbarkeit von Stirnzahnrädern aus dem Hochtemperatur-Thermoplast PEEK. Konstruktion 47, 351–357 (1995) (in German) Google Scholar
- Rösler, J.: Zur Tragfähigkeitssteigerung thermoplastischer Zahnräder mit Füllstoffen. Dissertation, Fakultät V. Technische Universität, Berlin, Germany (2005) (in German) Google Scholar
- Zahnt, B.-A.: Ermüdungsverhalten von Diskontinuierlich Glasfaserverstärkten Kunststoffen—Charakterisierungsmethoden, Werkstoffgesetze und Struktur-Eigenschafts-Beziehungen. Dissertation, Materials Science and Testing of Polymers, Montanuniversität Leoben, Austria (2003) (in German) Google Scholar