Projects undertaken in our group are highly focused basic research aimed at establishing technical feasibility, including the application of nanotechnology and biomimetics, to address issues related to the development/implementation of innovative materials and structures to meet the global challenge of light-weighting and resilience. They are categorised into three main themes as follows:

Flexible Mechanical Metamaterials and Lattices

Micro-architectured materials (mechanical metamaterials and lattices) exhibit unique combinations of material properties and show great promise for multi-functional applications. They respond to external loadings in complicated manners, which are strongly influenced by its substructural geometric and material response. Their mechanical response under more complex loading scenarios (e.g. multi-axial loading, post yield behaviour, buckling and dynamic loads) is not well characterised; in particular, if the lattices cannot be treated as strictly periodic (e.g. presence of finite boundaries, cell wall irregularities, etc). Our research aims to address some of these challenges: such as, developing theoretical bounds for their effective toughness and cross-property corrections, developing effective homogenised and constitutive models, understanding how effective bulk properties are affected by edge effects, and properties degradation during fatigue, etc.

On-going projects:

  • Edge effects in lattices
  • Fracture toughness and fatigue life of lattices
  • Development of effective models for lattice materials by mathematical homogenisation
  • Designing mechanical metamaterials for blast and impact attenuation

Resilient Lightweight Structures

Drivers for development of innovative lightweight technologies go beyond the low carbon agenda where there is a fast moving trend towards lightweight materials and structures for body armour and protection, building, packaging, etc. A significant challenge remains on how to increase the blast/shock resistance of lightweight systems in addition to enhancing its ballistic/spall performance without structural degradation. Our research focuses on how light-weight materials (foams, micro-architectured lattices, composites, etc.) and structural systems (sandwich panels, bonded structures etc.) respond to unconventional loadings and how they may be designed, or used in combination, to withstand more arduous operating conditions; including dynamic loading, thermal and mechanical stresses, enhanced resistance to spall and shock without structural degradation.

On-going projects:

  • Blast-resistant structural connections for lightweight panels
  • Integrating protective functionality into lightweight structures
  • Fluid-structure interactions: on energy and momentum transfer, damage characterisation, and the ultimate failure of structures in underwater explosions and air blasts
  • Synergistic interactions during combined blast and fragment loadings of structures
  • Real-time simulation of materials damage and structural deformation in a game environment

Enhancing Energy Absorption by Nanostructuring, Topological Optimisation and Biomimicry

Almost all materials are heterogeneous and are composed of domains of different materials (phases), such as a composite; or the same material in different states, such as a polycrystal; or the tessellation of material(s) in space to form lattices, such as cancellous bones or a leaf. Traditionally, energy absorption is based on the use of expendable sacrificial device(s) that are sufficiently ductile to absorb energy – typically through elasto-plastic deformation – as it undergoes large geometrical changes. Recent trend has moved towards using lightweight components where their ability to also absorb energy should be considered as an effusive property of interest. Our research aims to achieve this through topological optimisation of the material microstructure, at different length-scales, from which the component is made and/or introducing new phases (nano-fillers etc.), or both. As the physical phenomena of interest are on length scales that span tens of nanometers to the millimetres, novel computational approaches, such as phase-field modelling and molecular dynamics simulation, are employed to describe the mechanistic phenomenon operating at those scales.

On-going projects:

  • Phase-field models of large elastoplastic deformation at the microscale
  • Multi-scale damage modelling of CMC (ceramic matrix composites) and FRC (fibre-reinforced composites)