MODELLING OF LINEAR ELASTICITY AND VISCOELASTICITY OF THERMOSETS AND UNIDIRECTIONAL GLASS FIBRE-REINFORCED THERMOSET-MATRIX COMPOSITES – PART 2: HOMOGENIZATION AND NUMERICAL ANALYSIS
Marian Klasztorny, Daniel B. Nycz
Quarterly No. 1, 2022 pages 25-39
DOI:
keywords: thermoset, unidirectional glass fibre-reinforced thermoset-matrix composite, rheological modelling, experimental tests, numerical analysis
abstract The study continues the advanced analytical modelling of the linear elasticity and viscoelasticity of thermosets and unidi-rectional glass fibre-reinforced thermoset-matrix (UFRT) composites. The thermosets are isotropic materials with viscoelastic shear strains and elastic bulk strains, and the fibres are isotropic and elastic. The modified homogenization theory for UFRT composites, based on the selected tasks of the linear theory of elasticity, is developed. The modifications include a volumetrically equivalent cylindrical representative volume cell, solutions determined for an isotropic fibre based on the solutions for a mono-tropic (transversely isotropic) fibre, and certain modifications in the third task of the theory of elasticity. The viscoelastic con-stants of the thermoset are derived analytically and validated by fitting of the simulation and experimental shear strains on a logarithmic time scale in the unidirectional tension creep test. The viscoelastic constants of the UFRT composite are derived analytically and validated by fitting of the storage compliances corresponding to the new viscoelastic model and one obtained from the viscoelastic-elastic correspondence principle. The tension creep experiment is performed on the selected structural unsaturated polyester resin. Identification and validation are carried out for that thermoset and the corresponding UFRT com-posite with long E-glass fibres. All the modelling hypotheses are confirmed.