The Halpin‐Tsai equations: A review

Abstract The Halpin‐Tsai equations are based upon the “self‐consistent micromechanics method” developed by Hill. Hermans employed this model to obtain a solution in terms of Hill's “reduced moduli”. Halpin and Tsai have reduced Hermans' solution to a simpler analytical form and extended its use for a variety of filament geometries. The development of these micromechanic's relationships, which form the operational bases for the coniposite analogy of Halpin and Kardos for semi‐crystalline polymers, are reviewed herein.