AUTHOR=Parel Kurien S. , Chen Zhou , Etsion Izhak 

TITLE=Strengthening and Weakening Effects in Bilayer Coated Spherical Contact

JOURNAL=Frontiers in Mechanical Engineering

VOLUME=6

YEAR=2020

URL=https://www.frontiersin.org/journals/mechanical-engineering/articles/10.3389/fmech.2020.00023

DOI=10.3389/fmech.2020.00023

ISSN=2297-3079

ABSTRACT=<p>The effect of a middle-layer of thickness <italic>t</italic><sub>1</sub> with intermediate Young's modulus and yield strength in between a hard coating of thickness <italic>t</italic><sub>2</sub> and a softer spherical substrate of radius <italic>R</italic> on the yield inception of a coated system is investigated. Finite element method is used to model bilayer-coated spheres flattened by a rigid flat. It is found that the addition of the middle-layer can enhance or reduce the resistance to yield inception depending on its dimensionless thickness <italic>t</italic><sub>1</sub>/<italic>t</italic> and <italic>t</italic>/<italic>R</italic> where <italic>t</italic> is the total thickness of the two coating layers. Some practical results are presented, to enable optimum selection of bilayer coated system and prevention of undesired weakening effect.</p>