  Natural cellular materials, such as honeycombs, woods, foams, trabecular
bones, plant parenchyma, and sponges, may benefit from the disorderliness
within their internal microstructures to achieve damage tolerant behaviours.
Inspired by this, we have created quasi-disordered truss metamaterials (QTMs)
via introducing spatial coordinate perturbations or strut thickness variations
to the perfect, periodic truss lattices. Numerical studies have suggested that
the QTMs can exhibit either ductile, damage tolerant behaviours or sudden,
catastrophic failure mode, depending on the distribution of the introduced
disorderliness. A data-driven approach has been developed, combining
deep-learning and global optimization algorithms, to tune the distribution of
the disorderliness to achieve the damage tolerant QTM designs. A case study on
the QTMs created from a periodic Face Centred Cubic (FCC) lattice has
demonstrated that the optimised QTMs can achieve up to 100% increase in
ductility at the expense of less than 5% stiffness and less than 10% tensile
strength. Our results suggest a novel design pathway for architected materials
to improve damage tolerance.
