The yield behaviour of an array of metal-coated fibres

The biaxial compaction of a square array of metal-coated fibres (MCFs) is examined using the finite element method. The array is first compacted to a certain density using biaxial loading paths consistent with those for hydrostatic and closed-die compaction. The yield surfaces are then constructed at various stages of the densification. The size and shape of the yield surface depend on the loading history, relative density and on the fibre volume fraction. The yield surface after hydrostatic compaction has a corner at the initial loading point. However, the location of the corner on the yield surface after closed-die compaction depends on the relative density and the fibre volume fraction. The numerical results of the hydrostatic yield surface over a range of loading path are in good agreement with Fleck (1995) micro-mechanical model originally developed for the compaction of a random array of homogeneous particles.