Measurement and Interpretation of Fabric Dynamic Modulus

There is a need for information concerning the dynamic mechanical properties of textile materials if their performance characteristics are to be described completely. Of the methods available for measuring dynamic elastic modulus, the acoustic pulse-propagation technique seems to have many advantages in terms of versatility, accuracy, and simplicity of use with respect to textile materials. In this paper the sonic or initial dynamic modulus of a range of planar fibrous structures is described. The results for woven fabrics have been quantitatively analyzed in terms of the direction of orientation of the fabric relative to the warp and weft directions. The maximum and minimum values of dynamic modulus have been measured for a range of paper and paper-like materials and woven and knitted fabrics; they are interpreted in terms of their basic structural features. The translation of dynamic mechanical properties from fiber through yarn to finished fabric is explained in terms of the sonic-modulus measurements; the roles of yarn-bending properties and lateral pressure acting within the fabric have been investigated. Ideas for further development of the technique and its application to the study of fabric mechanics are presented.