Geometrical modeling of 3D woven spacer fabrics as reinforcement for lightweight sandwich composites.

Lightweight sandwich composites mainly utilize hollow textile preforms as their reinforcement. The production of such structures with desired mechanical properties requires monitoring of its repeat unit weight and fibre volume fraction (FVF) from designing stage itself. In this work, mathematical expressions have been developed using fabric geometrical parameters which can calculate the areal density and FVF of a repeat unit of 3D hollow woven structures. Five samples each of trapezoidal and rectangular spacer configurations were produced with different cell structural parameters and materials to validate the model. It was found that the computed results for both the weight and FVF were in good correlation with experimental results, with prediction accuracy being more than 90% in all cases. It was also found that with increase in the cell dimensions, the FVF of the expanded fabric decreases. [ABSTRACT FROM AUTHOR]