The development and deployment of large-scale load-bearing structures in the aeronautics
industry is an endeavour that can span several decades. The complex nature
of the materials involved and manufacturing processes used has historically led to
iterative design stages and lengthy testing and certification procedures.
In particular, composite materials, with all their promises, bring about several
interesting challenges. One of these is the relatively common incidence of manufacturing
defects. In the best-case scenario, these defects could mean that the component
is discarded; in the worst-case scenario, it could lead to premature structural
collapse.
Numerical methodologies specifically tailored for the design and optimisation
of large-scale composite structures enable faster, cheaper and more robust designs.
Therefore, this work presents a series of finite element methodologies to address the
challenges associated with large-scale composite structure development.
To address the iterative nature of the design stage and the need for robust
defect tolerance, this work proposes a numerical methodology to discretise a moving
boundary explicitly and a topology optimisation formulation centred on the energy
release rate of bodies with embedded cracks.
Additionally, to address the need for virtual testing frameworks this work
presents a multiscale material modelling methodology targeting modern modelling
approaches and computing architectures. The methodology is applied to a full-size
composite wing-box model.
Finally, this work develops an optimisation methodology combining the boundary
tracking capabilities, the energy release rate-based formulation and the
multiscale modelling workflow to enable the optimisation of large-scale composite
structures with manufacturing defects. The methodology is applied to a composite
stringer run-out model with a kissing bond defect.