Accession Number : ADA112357

Title :   Surface Traction and Crack Propagation in Delamination Wear.

Descriptive Note : Final rept. Feb 78-Sep 81,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR MFG AND PRODUCTIVITY

Personal Author(s) : Suh,Nam P ; Sin,Hyo-Chol

PDF Url : ADA112357

Report Date : Nov 1981

Pagination or Media Count : 189

Abstract : The mechanisms of surface traction and crack propagation and their functional relation to sliding wear are investigated experimentally and theoretically. According to the delamination theory of wear, the wear of materials strongly depends on friction because of the effect of surface traction on subsurface deformation and crack nucleation and propagation rates. Experimental studies using the cylinder-on-cylinder sliding arrangement with the iron based metals show that the coefficient of friction varies with the sliding distance and the environment. It is postulated that it is due to the changing contributions of three components of friction: due to the deforming asperities; plowing by wear particles and hard surface asperities; and adhesion. At any given loading contact only one of these mechanisms may operate and therefore, the local surface traction can vary from contact to contact, affecting the crack nucleation and propagation processes. The three mechanisms responsible for the generation of friction are analyzed using plasticity theory. The finite element analyses for the elastic and elastic-plsatic solids with subsurface cracks indicate that the cracks in sliding wear propagate in a ductile manner. Such fracture parameters as the crack-tip sliding displacement and the fracture strain are found to be useful in characterizing crack propagation.

Descriptors :   *Wear, *Friction, *Crack propagation, *Traction, *Metals, *Iron, *Finite element analysis, Coefficients, Surface analysis, Subsurface, Elastic properties, Plastic deformation, Nucleation, Fracture(Mechanics), Ductility, Adhesion, Quantitative analysis, Experimental data, Theorems

Subject Categories : Physical Chemistry
      Properties of Metals and Alloys
      Numerical Mathematics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE