Compression of thermosetting fabric materials

Thermoset fabric prepregs are available commercially in a number of weaves and are occasionally stitched. A study has been made of the deformation of these materials subjected to compressive forces normal to the plane of the fabric. The effects of change of scale, stitching, temperature, viscosity and weave have been investigated. From the experiments two significant features that may influence the processing and manufacture of parts formed from these materials were observed. The first was the percolation of the low viscosity resin through the fibres and the second was the substantial elastic recovery on removal of the load. In some cases this recovery was as much as fifty percent of the initial compression. In many manufacturing processes, the material undergoes various degrees of compression and the large elastic modulus observed in some of these mats is a potential source of distortion and of residual stresses after curing.