  The combination of Finite Element Method (FEM) simulation and experimental
photo-elasticity provides both qualitative and quantitative information about
the stress field in a polymer composite and particularly along the fibre-matrix
boundary. Investigations were made using model specimens containing up to five
parallel glass fibres loaded at angles from 0 to 15 degrees. The material
properties of the geometrically equivalent FE models are calibrated using the
experimental photoelastic outputs. In contrast to the experimental results, FE
simulations provide full 3D stress fields. For verification purposes, the 3D
stress fields are reduced to two-dimensional synthetic photoelastic phase
images, showing good agreement. Furthermore, detailed studies on the components
of the stress tensor, particularly statements concerning the shear transmitted
by fibre-matrix boundary, progressive fibre failure and the effect of load
angle variation are presented.
