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Influence of Indenter Tip Geometry and Poisson's Ratio on Load-Displacement Curve in Instrumented Indentation Test

계장화 압입시험의 하중-변위 곡선에 미치는 선단 형상 및 푸아송비의 영향

  • Lee, Jin Haeng (Research Reactor Mechanical Structure Design Division, Korea Atomic Energy Research Institute)
  • 이진행 (한국원자력연구원 장치설계부)
  • Received : 2014.04.06
  • Accepted : 2014.07.06
  • Published : 2014.09.01

Abstract

The tip geometries of the pyramidal and conical indenters used for micro/nano-indentation tests are not sharp. They are inevitably rounded because of their manufacturability and wear. In many indentation studies, the tip geometries of the pyramidal indenters are simply assumed to be spherical, and the theoretical solution for spherical indentation is simply applied to the geometry at a shallow indentation depth. This assumption, however, has two problems. First, the accuracy of the theoretical solution depends on the material properties and indenter shape. Second, the actual shapes of pyramidal indenter tips are not perfectly spherical. Hence, we consider the effects of these two problems on indentation tests via finite element analysis. We first show the relationship between the Poisson's ratio and load-displacement curve for spherical indentation, and suggest improved solutions. Then, using a possible geometry for a Berkovich indenter tip, we analyze the characteristics of the load-displacement curve with respect to the indentation depth.

Keywords

Instrumented Indentation Technique;Indenter Tip Geometry;,Finite Element Analysis;Spherical Indentation;Berkovich Indentation

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