The effects of frequency on fatigue threshold and crack propagation rate in modified and unmodified polyvinyl chloride

Samat, Noorasikin and Burford, Robert and Whittle, Alan and Hoffman, Mark (2009) The effects of frequency on fatigue threshold and crack propagation rate in modified and unmodified polyvinyl chloride. Polymer Engineering and Science, 49 (7). 1299 -1310. ISSN 1548-2634

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Abstract

The cyclic fatigue crack behavior of polyvinyl chloride (PVC), with (PVC-M) and without (PVC-U) chlorinated polyethylene (CPE) impact modifier, was studied. The effect of impact modifier upon fatigue crack growth rate and threshold was evaluated at frequencies of 1, 7, and 20 Hz. It was shown that the addition of CPE lowered the threshold stress intensity factor amplitude for crack growth (ΔKth) of PVC-M compared to that of PVC-U at lower frequencies, and that the effect became more pronounced at lower frequency. At lower stress intensity factor amplitudes (below ΔK = 1 MPa·m1/2), there was a slight difference between the crack growth rates of U- and M-PVC. The crack advance mechanism is investigated by microscopic observation of the crack tip process zone. Although the zone is relatively large in PVC-M, associated with higher toughness, it did not improve the fatigue crack growth resistance significantly. Fracture surface observations reveal a higher density of fibrils on the fatigued surface of PVC-M with the density, relative to that observed in PVC-U, reducing with frequency. It is therefore hypothesized that accelerated fibril failure is a mechanism of fatigue.

Item Type:	Article (Journal)
Additional Information:	4029/2839
Uncontrolled Keywords:	fatigue,pvc, pvc pipes, craze, fatigue threshold, frequency, modified PVC
Subjects:	T Technology > TP Chemical technology > TP1080 Polymers, plastics and their manufacture
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Engineering > Department of Manufacturing and Materials Engineering
Depositing User:	Dr Noorasikin Samat
Date Deposited:	30 Sep 2011 08:39
Last Modified:	11 Oct 2011 09:30
URI:	http://irep.iium.edu.my/id/eprint/2839

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