Residual stress effects on the compressive strength of unidirectional fibre composites

Compressive failure of unidirectional fibre composites by the kink band mechanism is analysed taking into account effects of residual stresses. Two criteria for determining the strength of the composite material have been investigated: Kink band formation at a bifurcation stress in a composite with perfectly aligned fibres, and kink band formation at a peak stress in a composite with fibre misalignments in the order of a few degrees as most commonly observed.

The interacting effects of fibre misalignments and residual stresses are studied for this reason. Results are also obtained for the interaction of fibre misalignments with other sources of imperfections such as variations in fibre volume fraction.