• A. Arteiro
  • L. F. Pereira
  • M. A. Bessa
  • C. Furtado
  • P. P. Camanho

To simplify the analysis and characterisation of composite laminates, an invariant-based approach to stiffness that takes the trace of the plane stress stiffness matrix as a material property was recently proposed. In the present work, a study based on micro-mechanical models brings new insight to this invariant-based approach. The Rule of Mixtures and the Halpin-Tsai models are used to establish the relations between the fibre volume fraction, the fibre/matrix stiffness ratios, and the trace-normalised engineering constants of unidirectional laminae and multidirectional laminates. For sufficiently high longitudinal fibre/matrix stiffness ratios and for fibre volume fractions between 50% and 70%, typical of advanced CFRPs, the variation of the trace-normalised longitudinal Young's modulus is within 6% for unidirectional laminae and within 1% for multidirectional laminates, supporting the definition of an invariant-based approach to stiffness based on a Master Ply concept and laminate factors derived thereof, defining clearly a domain of applicability of the invariant theory and confirming the empirical observations of the past.

Original languageEnglish
Pages (from-to)72-80
JournalComposites Science and Technology
Publication statusPublished - 2019

    Research areas

  • A. Laminate, A. Polymer-matrix composites (PMCs), C. Elastic properties, C. Laminate theory, C. Micro-mechanics

ID: 53459696