Surface Damage of Engineering Ceramics in Rolling Contact

Hertzian Contact Damage in Porous Alumina Ceramics

A study has been made of Hertzian contact damage in compressive shear stress field beneath the contact area. The observed microcrack density increases with grain size, porous and dense liquid-phase-sintered aluminas. Indentation stress–strain curves show increasing nonlinearity as the implying a threshold microstructural scale for crack initiation. In contrast, the micromechanisms controlling f...

Analysis of Surface Crack Growth under Rolling Contact Fatigue

Understanding the fatigue crack growth phenomenon in railheads requires a study of driving forces such as the crack tip opening and sliding displacements, under repeated rolling contact. Finite element simulations, allowing elastic-plastic deformation, and mixed-mode crack growth laws were utilized to demonstrate that the fatigue crack growth rates display a minimum after a finite amount of cra...

Rolling contact fatigue of surface coatings—a review

The aim of this review is to survey the state of the art relating to the rolling contact fatigue (RCF) investigation of various overlay coatings and also, to ascertain the influence of design parameters such as the type of deposition process, coating material and thickness on the RCF performance. Rolling contact fatigue is a significant factor in the failure of components in rolling/sliding con...

Contact damage in brittle coating layers: influence of surface curvature.

Fracture from indentation by a hard sphere on bilayer systems composed of curved brittle coating layers on compliant polymeric substrates is investigated, in simulation of dental crown structures. Glass plates 1 mm thick are used as representative of enamel/crown layers, and epoxy filler substrates as representative of support dentin. Specimens with curved surfaces are prepared by pressing the ...

Rolling Contact Fatigue in Ultra High Vacuum