Dual flat-spherical indentation for extracting elastic–plastic properties from rough metallic surfaces

Abstract

In this work, a dual flat-spherical indentation (DFSI) technique is developed for evaluating elastic–plastic properties from rough metallic surfaces. Since indentations on rough metallic surface produce dissimilar load–displacement (P-h) curves for the same material, finite element (FE) analyses and experiments demonstrate that DFSI method, in which rough surface is flattened by flat indenter before spherical indentation, extracts reproducible P-h curves from the flattened rough surface. Optimized indentation parameters are obtained by investigating the effects of surface roughness, flat indenter diameter, indentation depth on P-h curves. This allows to employ conventional spherical indentation (SI) method for property evaluation from DFSI P-h curves. The results are in good agreement with those from ideal smooth surface, and for rough surfaces (Ra = 0~20μm) common in engineering practice, the applicability of DFSI method is verified.

Keywords

• Spherical indentation
• Rough surface
• FEA
• Mechanical properties
• Stress–strain curves