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Fatigue crack growth in polyethylene
Author(s) -
Bucknall Clive B.,
Dumpleton Paul
Publication year - 1985
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760250602
Subject(s) - materials science , high density polyethylene , composite material , polyethylene , tension (geology) , crack closure , growth rate , fracture mechanics , crack growth resistance curve , paris' law , geometry , compression (physics) , mathematics
Fatigue crack propagation (FCP) rates are studied in 6 mm thick specimens of high density polyethylene (HDPE) containing razor notches, Centrally‐notched plates and single‐edg notched bars are subjected to sinusoidal tension‐compressio or tension‐zero cycling at 0.5 or 2.0 Hz under load control a room temperature; crack growth is monitored using a travelling microscope. After many thousands of cycles with no observable damage at the tip of the razor notch, a craze like zone begins to form. This zone grows slowly until it reaches the length characteristic of a mature crack at the same Δ K . Crack growth proper then begins. The number of cycles to initiate crack growth falls linearly with increasing Δ K at the razor notch Subsequent crack growth is determined both by the current value of Δ K and by loading history. When Δ K is increasing, FCP rates follow a standard Paris law curve. However, reduced, FCP rates are observed following an overload.