Measurement and simulation of micromechanical properties of nanostructured aggregates via nanoindentation and DEM-simulation

•Micromechanical properties depend on aggregate structure and binding mechanisms.•Deformation behavior was measured via indentation and was compared to DEM simulations.•The strength and stiffness of solid bridges were investigated.•The distribution of normal and radial stresses was compared to fracture behavior.

During the production of nanoparticles in large scale processes, usually larger aggregates are synthesized and subsequently redispersed to obtain the desired product properties. Dispersion processes are energy intense and not always predictable or even unsuccessful. The resistance of aggregates against redispersion and thus, the micromechanical properties strongly depends on the aggregate structure and the primary particle properties as well as on the binding mechanisms. The aim of this study was the investigation of the deformation and breakage behavior of aggregated structures composed of nanoparticles. This was done by comparing experimental and computational results. The larger scale simulations were based on a dimensioning of interaction forces and geometry and calibrated using experimental nanoindentation results. As a result the nature and strength of particle–particle interactions can be described. Furthermore, the distribution of normal and radial forces within the aggregates was compared to theoretical models of aggregate breakage.

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