The models of roughness description developed in a related paper that use simple parabolic functions to describe the peaks and valleys of measured rough profiles are tested with different contact mechanics models. The approximation with parabolas allows the calculation of each asperity curvature radius, a fundamental quantity for contact mechanics studies. After a review of the main contact mechanics models, some of them are selected: two different elastic models and two elastic-plastic ones, one with a discontinuity at the boundary between the elastic and the plastic region, and one with an additional elastoplastic transition region. The amplitudes of the contact zone and the load are calculated as a function of the interference of each profile with a rigid smooth flat surface for single parabolic asperities and for whole profiles extracted from five engineering surfaces with different roughness conditions. Selected results are presented that show big differences for the amplitude of the deformed zone and for the load supported by single parabolas using the different roughness description approaches and contact mechanics models. However, these differences are mitigated when the whole profiles are considered. As expected, the elastic models tend to overestimate the load when profiles with a certain degree of plasticity are under investigation. The roughness description approach based on the minimization of the least square error between the measured profile and the parabolic approximation (LMS c1 c2) gives the best simulation of the profile and does not show any drawback from a contact mechanics or numerical point of view. The combination of this approach with the contact mechanics model including the elastoplastic transition developed by Zhao, Maietta and Chang (ZMC) seems to guarantee the best results.
Rough Contacts Between Actual Engineering Surfaces- Part II: Contact Mechanics
CIULLI, ENRICO;
2008-01-01
Abstract
The models of roughness description developed in a related paper that use simple parabolic functions to describe the peaks and valleys of measured rough profiles are tested with different contact mechanics models. The approximation with parabolas allows the calculation of each asperity curvature radius, a fundamental quantity for contact mechanics studies. After a review of the main contact mechanics models, some of them are selected: two different elastic models and two elastic-plastic ones, one with a discontinuity at the boundary between the elastic and the plastic region, and one with an additional elastoplastic transition region. The amplitudes of the contact zone and the load are calculated as a function of the interference of each profile with a rigid smooth flat surface for single parabolic asperities and for whole profiles extracted from five engineering surfaces with different roughness conditions. Selected results are presented that show big differences for the amplitude of the deformed zone and for the load supported by single parabolas using the different roughness description approaches and contact mechanics models. However, these differences are mitigated when the whole profiles are considered. As expected, the elastic models tend to overestimate the load when profiles with a certain degree of plasticity are under investigation. The roughness description approach based on the minimization of the least square error between the measured profile and the parabolic approximation (LMS c1 c2) gives the best simulation of the profile and does not show any drawback from a contact mechanics or numerical point of view. The combination of this approach with the contact mechanics model including the elastoplastic transition developed by Zhao, Maietta and Chang (ZMC) seems to guarantee the best results.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
