Multiscale approach for identification of transverse isotropic carbon fibre properties and prediction of woven elastic properties using ultrasonic identification

In this work the possibility to reverse engineer the transverse isotropic carbon fibre properties from the 3D
homogenized elastic tensor of the UD ply for the prediction of woven ply properties is explored. Ultrasonic
insonification is used to measure the propagation velocity of both the longitudinally and transversally polarized
bulk waves at various symmetry planes of a unidirectional (UD) Carbon/Epoxy laminate. These velocities and
the samples' dimensions and density are combined to obtain the full 3D orthotropic stiffness tensor of the ply.
The properties are subsequently used to reverse engineer the stiffness tensor, assumed to be transversely isotropic,
of the carbon fibres. To this end, four micro-scale homogenization methods are explored: 2 analytical
models (Mori-Tanaka and Mori-Tanaka-Lielens), 1 semi-empirical (Chamis) and 1 finite-element (FE) homogenization
(randomly distributed fibres in a Representative Volume Element). Next, the identified fibre properties
are used to predict the elastic parameters of UD plies with multiple fibre volume fractions. These are then
used to model the fibre bundles (yarns) in a meso-scale FE model of a plain woven carbon/epoxy material.
Finally, the predicted elastic response of the woven carbon/epoxy is compared to the experimentally obtained
elastic stiffness tensor. The predicted and measured properties are in good agreement. Some discrepancy exists
between the ultrasonically measured value of the Poisson's ratio and the predicted value. Nonetheless, it is
shown that virtual identification and prediction of mechanical properties for woven plies is feasible.

Publication year:2018

Keywords:Constituent property identification, Multiscale modelling, Textile composites, UD composites, Ultrasonic testing

BOF-keylabel:yes

BOF-publication weight:3

CSS-citation score:1

Authors:International

Authors from:Private, Higher Education

Accessibility:Closed