Abstract:
Limited capacity in launch vehicles was overcome by the usage of deployable structures. They
allow large structures to be packed into compact configurations. Woven fibre composite laminates
eliminate the need of mechanical actuators which are heavy and complex to operate. Further the
woven fibre composite laminates has gain a significant recognition in the aerospace industry,
because of their self-deploying nature, high strength to weight ratio and tailorable material
properties. However, these structures experience extreme curvatures during stowage, which result
in change in mechanical properties of the material. Hence, it is important to predict the changes in
mechanical behaviour of woven fibre composites to optimize future designs. Several studies have
been conducted to capture the variations in mechanical properties by changing various
characteristics of woven fibre laminates using analytical methods and numerical modelling
techniques due to the highly expensive experiment procedures. Numerical modelling techniques
provide high leverage over the other methods due to complex nature of the material and availability
of high computational power.
A meso-mechanical representative unit cell (RUC) is generally used to represent woven fibre
composite for predicting mechanical behaviour in numerical modelling environment. Several
parametric studies have been conducted to predict the effect of various geometric and material
properties on mechanical behaviour. However, relative positioning of tows has not been studied
in detail. The objective of this research is to capture the influence of phase difference between two
plies on change in material stiffness of a two-ply plain weave laminate using homogenized
Kirchhoff plate based meso-mechanical unit cell modelling technique. First, a series of mesomechanical
RUC models with different relative positionings of tows were modelled. Then the
constitutive relationship was derived for each RUC model. Here, 0°, 90° and 180° phase difference
cases were considered and variation of extensional stiffness, shear stiffness, bending stiffness and
twisting stiffness along with phase differences were analysed. Then, the obtained finite element
results were compared against the experiment results available in literature.
It has been shown that, the axial and bending stiffness values have considerable variations and
minimal change has been observed in shear and torsional stiffnesses with relative positioning of
tows. The experimental validation concludes that, the developed meso-mechanical unit cell model
is capable of capturing the bending stiffness with a good accuracy but overpredicts the axial and
shear stiffnesses. Further refined analysis on phase difference angle of tows considering cases in
between can be used to improve the accuracy of prediction. Further consideration should be given
on the models with asymmetric relative positions, that may lead to a shift in neutral plane of RUC
and eventually affect the axial-bending coupling response of the material.
Citation:
Gowrikanthan, N., & Mallikarachchi, H.M.Y.C. (2021). Influence of relative positioning of tows on mechanical properties of thin woven composites [Abstract]. In P. Hettiarachchi (Ed.), Proceedings of Civil Engineering Research Symposium 2021 (p. 15). Department of Civil Engineering, University of Moratuwa.