Ultrasonic system for in-plane paper characterisation.

An ultrasonic system that enables the measurement of paper properties like anisotropy or filler content is fully described in this paper. The system is composed of a measuring head that integrates 16 ultrasonic bimorph circumferentially disposed transducers. The hardware responsible for the emission and the reception tasks is PC controlled by means of an acquisition board and by specifically developed software. The experimental results obtained present a very good agreement with others obtained by classic methods, namely destructive tests, and allow evaluation of paper properties such as tensile stiffness index, tensile stiffness orientation angle, anisotropy and filler content, with good accuracy. [ABSTRACT FROM AUTHOR]