Mesh-free micromechanical modeling of inverse opal structures

The application of mesh-free discrete element method (DEM) for modeling of macroporous inverse opals is proposed. The developed and implemented DEM-based strategy is applied to analyze stiffness and strength of inverse opals made of pure silica and inverse opals coated with titania layers of various thicknesses. Also, the influence of the porosity of the initial packing on the properties of the material is investigated. Simulation results have shown that due to the heterogeneous macroscopic structure and unequal material distribution in nodes, struts or near interstitial pores, strong inhomogeneities of the stress distribution arise. Spots of localized stresses located near the interpore openings are the sources of initial defects and small interpore cracks. Reducing the overall porosity or an additional coating of the structure with a titania layer allows to partially homogenize and improve its mechanical properties. It was shown that the obtained simulation results are in very good agreement with previous studies. Despite large computational effort, the performed analysis confirms the high efficiency of the proposed DEM-based approach and demonstrates its great potential for use in problems of a similar class: for modelling of complex-structured multicomponent materials.