Estimation of the reinforcement factor xi for calculating the transverse stiffness E2 with the Halpin-Tsai equations using the finite element method Articles uri icon

publication date

  • June 2015

start page

  • 402

end page

  • 408


  • 124

International Standard Serial Number (ISSN)

  • 0263-8223

Electronic International Standard Serial Number (EISSN)

  • 1879-1085


  • In this work, an estimation of the reinforcement factor of the Halpin-Tsai equations used to calculate the transverse stiffness E-2 is provided. An improved estimation of the value xi = 2 originally proposed by Halpin and Tsai is given through a set of finite element analyses that consider randomly distributed unidirectional fibers for different volume fractions. The analysis overcomes the original hypothesis of a square array distribution of fibers in the transverse plane. It is concluded that a value of xi = 1.5 is a better estimation for the usual volume fractions found in practice for a unidirectional lamina of fiber reinforced composites.


  • reinforcement factor; transverse stiffness; unidirectional lamina; finite element analysis