An investigation into the performance of composite hat stringers incorporating nanocomposites using a multiscale framework

In this paper, an effort has been made to investigate the incorporation of carbon nanotubes in structural composites in order to improve damage characteristics, such as delamination. The nanocomposite material is introduced in the damage-prone regions of complex aerospace stiffener sections; the methodology proposed is an alternative to traditional approaches used to suppress delamination in composites, such as the use of metallic fittings. Numerical simulations are conducted using a multiscale modeling framework. The effective properties of the nancomposites are computed using a micromechanics-based approach and the results are compared with those obtained using a Kalman filter algorithm. The information is then used to analyze the structural response of a hat stringer using detailed finite element models. The stringer is analyzed under different loading conditions and varying levels of defects in the structure. Results obtained indicate that the use of nanocomposites improves the structural performance by improving the initial failure load. It is anticipated that the use of carbon nanotubes during the manufacturing process will help delay the onset of initial damage and damage growth, which can ultimately lead to a more robust structural design with enhanced performance against unique composite failure modes.