% \documentclass[runningheads]{llncs} % \begin{document} % \noindent A finite element (FE) based limit analysis procedure for the evaluation of the collapse load of human proximal femur coupled with patient-specific Computed Tomography (CT) imaging is presented. The onset of the femoral failure is predicted in the framework of the static approach of limit analysis with the aid of an iterative procedure that, within an accurate digital twin FE model of the bone, redistributes stresses through successive elastic analyses until a plastically admissible stress state is achieved. A lower bound to the collapse load is so evaluated. It is worth noting that plasticity in bones, at the macroscale, arises from fibrillar sliding which ensures plastic deformation and energy dissipation; at the microscale, occurs when hydrogen bonds within individual collagen molecules break, followed by bond rupture and intermolecular sliding within collagen fibrils. Indeed, plasticity is here assumed only to define a domain of admissible stresses, the relevant feature is in fact that, unlike conventional nonlinear FE approaches that often require complex post-elastic constitutive assumptions to predict failure, the only required information are geometry of the structure and material strengths of the bone’s cortical and trabecular tissues. Patient-specific CT imaging is used to this aim. It allows both a detailed reconstruction of femoral geometry and a precise determination of bone density-dependent strength parameters. A comparison of the obtained numerical findings with experimental ones from cadaveric femurs is used to show the effectiveness of the promoted approach which provides reliable lower-bound estimates of femur collapse load, particularly when exponential-type strength–density relations are adopted. Although limited to a single loading condition, the obtained results suggest that the promoted method assures clinical applicability and could serve as a practical tool for human fracture risk assessment. \end{document}