Acoustical characteristics of textile materials

An attempt is made to identify the acoustical characteristics of textile materials using precision woven monofilament fabrics as model textiles. The experiments try to eliminate the effect of entrapped air pockets in the fabric on an ultrasound wave field. The results of the experiment reveal that the power consumption of the ultrasound horn remains practically constant after introducing the textile at different positions in the standing wave field. Measurements of transmitted acoustic pressure amplitude through the textile reveal that fabrics form an almost transparent boundary for acoustic waves. A simple model involving the structural and hydrodynamic characteristics of the textiles is proposed to determine their acoustic impedance, and the results of the experiments are explained on the basis of this model. The overall conclusion of the study is that in the absence of entrapped air, textiles do not have any individual impact on the ultrasound wave field.