Journal of the Korean Society for Precision Engineering (한국정밀공학회지)

Korean Society for Precision Engineering (한국정밀공학회)
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An Analysis of the Mechanical Characteristics of the Knife Edges used in the NPL Watt Balance

질량신정의 구현을 위한 NPL 와트발란스 나이프에지의 기계적 특성 분석

  • 최인묵 (한국표준과학연구원) ;
  • ;
  • 우삼용 (한국표준과학연구원 기반표준본부 역학그룹)
  • Published : 2008.04.01
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Abstract

Of the seven base units of the international system of units, only the kilogram is still defined in terms of a material artifact. One of the experimental approaches opening the way to a new definition of the kilogram is the watt balance To improve the performance of the NPL watt balance, we need to quantify and reduce hysteresis effects in the balance knives. In this paper, we discuss the mechanical characteristics of the knife edges used in the NPL watt balance. The hysteresis mechanism is analyzed using the finite element method. It is found that the cause of hysteresis is not normal stress but shear, and the deformation of the flat, rather than the knife, is an important factor in the hysteresis mechanism. The study presented here, using finite element analysis, suggests that parameters such as material property, tip radius and knife straightness can be more important than others, such as friction coefficient, tip angle, etc.

Keywords

References

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