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International Journal of Polymer Science
Volume 2015, Article ID 275937, 9 pages
http://dx.doi.org/10.1155/2015/275937
Research Article

Tensile Behavior of Polyetheretherketone over a Wide Range of Strain Rates

1Institut de Recherche en Génie Civil et Mécanique, UMR CNRS 6183, École Centrale de Nantes, L’UNAM, 1 rue de la Noe, BP 92101, 44321 Nantes Cedex 3, France
2Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University, P.O. Box 80248, Jeddah 21589, Saudi Arabia

Received 13 March 2015; Accepted 24 May 2015

Academic Editor: Jan-Chan Huang

Copyright © 2015 Zakaria El-Qoubaa and Ramzi Othman. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Polyetheretherketone (PEEK) is used in several engineering applications where it has to bear impact loads. Nevertheless, the tensile behavior has only been studied in the quasi-static range of loading rates. To address the lack of data in the impact strain rate range, the tensile mechanical behavior of PEEK is investigated at room temperature over a large range of strain rates (from 0.001 to 1000/s). The macroscopic volume change is studied under uniaxial tension using digital image correlation (DIC) method, showing a significant dilatation that reaches 16% at a logarithmic axial strain of 40%. The true stress-strain behavior is therefore established based on the measured volume change. Elsewhere, the yield stress shows a significant sensitivity to strain rate. Besides, a new constitutive equation is proposed to take into account the increase in strain rate sensitivity at high strain rates. It assumes an apparent activation volume which decreases as the strain rate increases. The new constitutive equation gives similar results when compared to the Ree-Eyring equation. However, only three material constants are to be identified and are physically interpreted.