Evaluation of Measurement Uncertainty of Universal Calibration Machines

摘要

The universal calibrating machines are used extensively in industrial, governmental, and military laboratories for the calibration of various force transducers (load cells, dynamometers, proving rings, and other force measurement devices). There are many important factors that might affect the measurement process. These factors may be summarized as: the possibility of existing friction between moving and stationary parts, the rotational effect of the reference standard load cell, the repeatability of measurements, the effect of the number of runs, the eccentricity effect, hysteresis and drift. The overall uncertainty of a measurement consisting of individual uncertainties was evaluated. A mathematical model is proposed for the estimation of the expanded measurement uncertainty. A numerical example is given to show the application of the proposed method.