Size effects in single asperity frictional contacts
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Two sets of indentation and sliding discrete dislocation plasticity analyses are carried out to investigate the initiation of frictional sliding between a rigid asperity and a single crystal film. Most calculations are carried out for sinusoidal asperities, but for comparison purposes some results are presented for wedge-shaped asperities. In one set of calculations the friction coefficient is evaluated from separate indentation and sliding calculations while in another set the indentation and sliding processes are carried out sequentially. Both sets of friction calculations predict a similar friction stress versus contact size relation with the friction stress dominated by adhesion at small contact sizes, being plasticity governed at large contact sizes and being strongly size dependent at intermediate values of the contact size. Remarkably, the predicted values of the friction coefficient are similar for both sets of calculations even though the predicted deformation fields and dislocation structures differ significantly. © 2007 IOP Publishing Ltd.
author list (cited authors)
Deshpande, V. S., Balint, D. S., Needleman, A., & Van der Giessen, E.