Numerical simulation of deformation and fragmentation of fractal-like nanoaggregates

Abstract

A flexible fractal-like aggregate model was used to study deformation and fragmentation of the structure of fractal-like aggregates via their impaction with rigid rough surface. Aggregates were conveyed one at the time towards a surface under vacuum conditions. The number of primary particles remaining in each fragment, ratio of average fragment radius of gyration after impaction to the average fragment initial radius of gyration and ratio of average coordination number to the initial coordination number were monitored for each individual aggregate. Results demonstrate that depending on the impact velocity, the fractal dimension of the aggregate, the strength of bonds between primary particles, the stiffness of the aggregate structure and the diameter of primary particle composing an aggregate, restructuring or breakage of the aggregate occur. Moreover, in the analysis of the ratio of coordination number of aggregates after impaction to the initial coordination number, three regimes were distinguished: first no deformation at low impact velocities, second restructurisation regime and finally fragmentation regime where partial or total fragmentation of aggregates was observed.