The Elastic Properties of Chopped Strand Mat and Woven Roving in G.R. Laminae

Abstract

The elastic properties of 450 gr/m2 chopped strand mat (CSM) and 800 gr/m2 woven roving (WR) reinforced polyester laminae were experimentally determined using the tensile and the rail shear tests. It was found that the CSM laminae did not comply with the (general) assumption of transverse isotropy; the Young's moduli (E) measured in two mutually perpendicular directions were found to differ by 18 percent. A difference of 27 percent in the E of the two (mutually perpendicular) principal material directions of the WR could be partially explained in terms of the volume fraction of fibres in these directions. The elastic properties of both types of laminae were predicted from the resin and fibre properties and the fibre volume fraction using equations suggested by Hull for the CSM and an analysis of Ishikawa for the WR. Agreement between the predicted and experimental values was reasonable to excellent.