Accurate modelling of the mechanical behaviour of elastomeric materials including microscale filler particles represents a challenge in terms of the range of length scales involved. This difficulty arises because the macroscopic continuum-scale properties are strongly influenced by chemical and physical interactions at the atom-scale and mesoscale. Modelling of these materials is affected by the choice of filler particles, the particle size distribution, the percentage filler content in addition to manufacturing processes employed for the bulk material.
This PhD project will tackle example material systems using a combination of molecular dynamics computation and continuum modelling. The aim is to characterise the local mechanical properties that result from interaction between the microscale filler particle surfaces and the surrounding polymer. An example elastomer of interest is PDMS, whereas the filler particles may be glass, a thermoplastic, or an inorganic species. These properties will inform a description of the interface regions around filler particles, the properties of which vary according to distance from the filler surfaces and the nature of the surrounding polymer. The localised mechanical parameters and the nature of the interface region will then be used to develop constitutive relations within micro-mechanical models of the composite and homogenization from the mesoscale to the continuum scale, allowing the prediction of the linear elastic (low strain deformation) region of stress / strain curves. These models could potentially aid in the design and down-selection of new materials with optimised or novel properties.
The project will involve a combination of computational and modelling work. A suitable candidate should have (or be expected to soon obtain) a good degree in a STEM subject, and be willing to engage with existing computational physics / chemistry codes and techniques to tackle the molecular dynamics aspects. The scale-up process and micromechanical modelling will also require a student with strong analytical skills.