Filament Misalignment and Composite Strength Available to Purchase

The effect of random filament misalignment on the strength of a unidirectionally reinforced composite is investigated. The bundle strength theory of parallel, noninteracting filaments, which many composite tensile strength theories incorporate as a starting point, is reviewed. The bundle strength theory is then extended to include random filament misalignment. The tensile strength of a unidirectional composite with misaligned filaments is discussed. It is concluded that filament misalignment, at least to that degree which may reasonably arise during composite fabrication, is much less detrimental to composite tensile strength than a distribution of filament breaking strains. Application of random filament misalignment to composite shear strength is discussed and forms a basis for a partial explanation of the observed higher shear strengths of composites made from graphite tow rather than graphite yarn.