Aw. Eberhardt et Bs. Kim, Stress intensity factors for a vertical surface crack in polyethylene subject to rolling and sliding contact, J BIOMECH E, 120(6), 1998, pp. 778-783
Citations number
25
Categorie Soggetti
Multidisciplinary
Journal title
JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME
Fitting wear is a dominant form of polyethylene surface damage in total kne
e replacements, and may originate from surface cracks that propagate under
repeated tribological contact. In rite present study, stress intensity fact
ors, K-iota and K mu, were calculated for a surface crack in a polyethylene
-CoCr-bone system ln in the presence of rolling or sliding contact pressure
s. Variations in crack length and load location were studied to determine p
robable crack propagation mechanisms and modes, The crack tip experienced a
wide range of mixed-mode conditions that varied as a function of crack len
gth, load location, and sliding friction. Positive K-I values were observed
fur shorter cracks in rolling contact and for all crack lengths when the s
liding load moved away from the crack. K-II was greatest when the load was
directly adjacent to the crack (g/a = +/-1), where coincidental Mode I stre
sses were predominantly compressive. Sliding friction substantially increas
ed both K-I(max) and K-II(max). The effective Mode I stress intensity facto
rs, K-eff, were greatest at g/a = +/-1, illustrating the significance of hi
gh shear stresses generated by loads adjacent to surface cracks. K-eff tren
ds suggest mechanisms far surface pitting by which surface cracks propagate
along their original plane under repeated reciprocating rolling or sliding
, and turn in the direction of sliding under unidirectional sliding contact
.