METHOD OF MEASURING MEAN SIZE OF GRAIN OF SHEET Russian patent published in 2005 - IPC

FIELD: measuring engineering.

SUBSTANCE: method comprises exciting a given mode of Lamb wave (a or s) initially at frequency f and then at frequency f_j. The axes of fluidic acoustical converters are oriented at angles θ and θ_j from the normal to the sheet plane, respectively. The same converters receives echo-signals reflected from the edge of the sheet and covering distance l and l_j in it, and the amplitudes of the pulses and their ratio are then determined. Frequencies f and f_j as well as distances from the edge of the sheet to the site where the beam of longitudinal waves are incident on the surface of the sheet l and l_j are related as f_j = fn, l_j = 1/n, where n>1, angles θ and θ_j are determined from the dispersion curves and given thickness of the sheet h. The mean size of the grains is determined from the formula proposed.

EFFECT: enhanced reliability.

2 dwg