JAPD 2007 Abstract

An Elastic-Plastic Finite Element Analysis of Interacting Asperities in Contact with a Rigid Flat

Hassan Eid and George G Adams


A three-dimensional elastic-perfectly-plastic finite element model of asperity interaction has been developed. This model consists of two connected neighboring deformable hemispheres which are brought into contact with a flat rigid surface. For two asperities of the same height and same radius, as the approach of the rigid surface is increased, the contact area changes from two isolated nearly circular contacts, to a wasp-waist area, and finally to a single oval shaped contact region. For asperities of different heights the results can be qualitatively similar to those for equal heights, but can also exhibit a shielding effect in which the first contact grows to eventually encompass the second lower peak. Results are given using dimensionless quantities for the force vs. interference, and the contact area vs. interference. These relationships are plotted for different asperity height differences and asperity separations. Also provided are graphs of the contact area boundary for different values of the approach. Curve-fit equations are presented as an aid in using this work as a building block in a statistical multi-asperity contact model which directly includes the effect of asperity interactions.

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