Final report on force key comparison CCM.F-K4.a and CCM.F-K4.b for 4 MN and 2 MN forces

Abstract

This report gives the results for the Comité International des Poids et Mesures (CIPM) key comparisons in force, designated by comparison numbers CCM.F-K4.a and CCM.F-K4.b, for the maximum force values of 4 MN and 2 MN, respectively. Eight National Metrology Institutes, employing nine national force standard machines, participated in these comparisons. The National Institute of Standards and Technology (NIST) served as the pilot institute for these comparisons. Four transducers were employed in two star circulations, with one pair circulated among the participants of CCM.F-K4.a and the other pair circulated for CCM.F-K4.b. The transducers exhibited only minor drift over the circulation time periods; however, the results for one of the transducers circulated for CCM.F-K4.a were limited by excessive sensitivity to orientation about the axis of force application.Two analysis approaches for calculating Key Comparison Reference Values (KCRV) are presented, one employing a classical consensus mean analysis and the other based on weighted mean calculations. Reasonable correlation in the conclusions for individual transducers is seen between the two approaches. The weighted mean approach is extended to yield a KCRV for each of the two force values from the combined data from all of the associated transducers. One of the seven participants at 4 MN, and two of the nine participants at 2 MN, have expanded uncertainty intervals that lie outside of the expanded uncertainty bands for the corresponding weighted mean KCRVs.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).