The team, led by Shaker Meguid from the Mechanics and Aerospace Design Lab at the University of Toronto, Canada, is interested in converting polymeric thermoset adhesive resins into multifunctional materials that performs multiple "structural" and "non-structural" functions simultaneously. The multifunctionality will be achieved via the dispersion of very small amounts (for example, concentrations of 0.1–2%) of carbon nanotubes and nanowires.

Crack monitoring

In their work, the multifunctionality of the adhesive resin will be manifest in the significant improvement in the electro-mechanical properties. The resulting tailored properties will have a significant impact on the ability to self-health monitor an aircraft's primary structures for cracks, delamination and other sources of failure.

The development of such smart adhesives for use in future aircraft will provide early warning of impending catastrophic failures in primary structures. The group is currently investigating the effect of uniformly dispersed, aligned and agglomerated carbon nanotubes on the electrical conductivity of multifunctional nanocomposites. Unlike earlier Monte Carlo simulations, the current work employs a novel network recognition approach to determine current continuity and critical percolation level. The researchers employed periodically connective paths and these led to the reduction of the finite size of the representative volume element that contains the carbon nanotubes (CNTs).

Design tool

The results of their study, which are in good agreement with existing experimental work, reveal that the highest electrical conductivity occurs when the CNTs are partially rather than perfectly aligned. The data further shows that the presence of agglomerated CNTs results in a higher conductivity at and close to the percolation threshold, but limits the increase in the electrical conductivity of the nanocomposite with increased fractions of CNTs.

The group's results provide a new, robust and computationally efficient model that can be adopted as a predictive tool to characterize and evaluate electrical conductivity in multifunctional nanocomposites.

Further details can be found in the journal Nanotechnology.