Uncertainty analysis of metal-casting porosity measurements using Archimedes' principle

A detailed uncertainty-analysis model is developed for metal-casting porosity measurement using Archimedes' principle. The model is used to investigate the influence of liquid density on the sensitivity coefficients in the uncertainty propagation equation. The sensitivity coefficients are found to be very large, resulting in significant magnification of uncertainties in weight measurements and liquid and theoretical density estimates. Increasing the density of the liquid results in a decrease in sensitivity coefficients and an improvement in porosity accuracy. A numerical example is given to demonstrate the process of estimating the measurement uncertainties and typical uncertainties that can be expected in metal-casting porosity measurements.