AbstractThe focus of this work is on matrix-inclusion nanocomposites and their mechanical behavior, particularly taking into account inelasticity and damage. We propose a nonlocal damage model based on a micropolar continuum theory which captures the heterogeneous interphases in the nanostructure. The model is valid for a large range of matrix-inclusion nanocomposites. The effects of the interaction between nanoparticles, the thickness of the interphase and the size of nanoparticles on the overall mechanical properties of the nanocomposite are analyzed to optimize the microstructure of the nanocomposites. 3D micromechanical simulations are conducted for the particular example of a tailored, ultrastrong nanocomposite. It has extraordinary mechanical properties, and to date, is the strongest synthetic inorganic-organic nanocomposite. The simulation results are compared to experimental data from microcantilever beams for different process temperatures.