A nonlinear micromechanical model for progressive damage of vertebral trabecular bones

A new three-dimensional (3D) nonlinear micromechanical analysis is proposed to predict the overall mechanical response to damage evolution of the vertebral trabecular bone (VTB) highly porous microstructure. Towards that goal, a nonlinear micromechanical model, based on the 3D parametric high fidelity generalized method of cells (HFGMC) micromechanics, is extended to include progressive damage. The damage is initiated at the local subcell and its evolution is carried out using a strain-softening method. The nonlinear HFGMC behavior including damage evolution is first verified by examining its ability to predict the experimental nonlinear compression stress-strain response of printed polymeric VTB highly porous microstructure. Next, predicted HFGMC pre- and postultimate failure for native VTB representative unit cells (RUCs) harvested from different vertebrae of human cadavers (n = 10) are carried out. Some of the latter predictions were compared to reported values found in the literature. The proposed nonlinear HFGMC micromechanical model with evolving damage can predict the overall nonlinear behavior, including postultimate range.