Mechanical properties of composites with an icosahedral fibre packing reinforcement

Abstract Continuous fibre composites exhibit an elastically isotropic behaviour when the fibres are aligned along six directions, each one being a fivefold symmetry axis. The elastic properties of such quasiperiodic packings are theoretically derived and compared with various periodic packings. Practical rules of construction of such composites are presented. They are used in the elaboration of cubic samples with steel fibres embedded in a polymeric matrix. Compression tests are carried out, but the expected isotropic elastic properties are not measured. Numerical simulations confirm that this apparent anisotropy is related to the shape of the samples and that isotropy is expected with spherical samples. Finally, the effect of the fibre interactions is also investigated.