Multiscale modelling framework for the mechanical properties of illite

Clay is one the most important materials in earth's crust and has wide applications in geotechnical, environmental, and biomedical engineering. It has complex mechanical properties due to its particulate nature and complex physico-chemical interactions between primary particles. In this presentation, a multiscale framework will be presented, linking the mechanical properties of illite from atomistic up to macroscopic scales. Illite is a typical type of clay with flexible plate-like particles. The framework includes the study of inter-particle interaction at atomistic scale through free energy perturbation calculations with molecular dynamics simulations, from which the potential of mean force will be used to calibrate the coarse-grained force field to be used in meso-scale simulations. The modes of deformation and mechanical response of the mesoscopic systems are incorporated into a thermodynamically consistent constitutive model describing the small-strain elastic stiffness of illite clay at macroscopic level. The simulation results are compared with experimental results on the same material. The framework can provide good guidance on similar multiscale study on physico-chemical properties of clay to facilitate efficient material modification targeting for a greener civil engineering construction practice and has potential application in the investigation of other geomaterials.

National Science Foundation (NSF) [ACI-1548562] under the grant no. 1702689.