1,720,983 research outputs found
Characterization of Femoral Nonlinear Behavior Through Patient-specific CT-based FE Modeling
No full textFemoral biomechanics via CT-based finite element models with nonlinear constitutive response
No full textRisk assessment of femur failure: a computational model accounting for the influence of metastatic lesion
No full textA computational insight on damage-based constitutive modelling in femur mechanics
No full textThe present paper addresses femur failure mechanics, by numerically investigating the influence of brittle/ quasi-brittle bone constitutive description when combined with several failure criteria and different descriptions of bone ultimate parameters. Starting from computed tomography images of an experimentally-tested cadaveric femur, the bone geometry has been reconstructed through a semi-automatic segmentation procedure, and patient-specific material properties have been derived. Loading-induced loss of structural integrity has been simulated through a progressive thermodynamically-based damage model, by introducing different strain and stress-based damage evolution laws. An in-house displacement-driven incremental approach has been implemented in a finite element framework to mimic the in-vitro experimental procedure. An energy-based regularization technique allowed to obtain results which are mesh independent and therefore physically meaningful. Depending on the adopted modelling strategy, significant differences in terms of yield and failure load, as well as in fracture patterns, have been numerically experienced. Comparisons between the proposed numerical results and the available experimental outcomes have been carried out. For the femur model herein analysed, an elastic quasi-brittle bone description combined with strain-based failure criteria seems to be more effective in predicting the mechanical behaviour up to the fracture. Presented mesh-independent results therefore contribute to justify the need of damage-based approaches for predicting in an effective way failure mechanisms of femurs
Elasto-damage mechanics of osteons: A bottom-up multiscale approach
No full textIn this paper, a multiscale rationale is applied to develop a bottom-up modelling strategy for analysing the elasto-damage response of osteons, resulting in a first step towards a refined mechanical description of cortical bone tissue at the macroscale. Main structural features over multiple length scales are encompassed. A single osteon is described by considering a multi layered arrangement of cylindrical lamellae and accounting for both lacunar micro-voids and thin interlamellar regions, these latter modelled as soft interfaces. A multi-step homogenization procedure has been conceived and numerically applied to describe the equivalent mechanical response of osteon constituents, upscaling dominant subscale mechanisms. A progressive stress based damage approach has been implemented via a finite-element technique, allowing to describe interlaminar and/or intralaminar brittle failure modes. Proposed approach has been successfully validated by numerically reproducing available experimental tests of isolated osteons under different loading conditions. Present histologically-oriented multiscale model revealed to be sound and consistent, opening towards further insights about the influence on bone biomechanics of through-the-scales biophysical/biochemical alterations, possibly related to ageing or diseases
Improving the manufacturing of 3D printed insoles through a combined experimental and topology optimization approach
No full text
Elasto-damage mechanics of osteons: A bottom-up multiscale approach
No full textIn this paper, a multiscale rationale is applied to develop a bottom-up modelling strategy for analysing the elasto-damage response of osteons, resulting in a first step towards a refined mechanical description of cortical bone tissue at the macroscale. Main structural features over multiple length scales are encompassed. A single osteon is described by considering a multi layered arrangement of cylindrical lamellae and accounting for both lacunar micro-voids and thin interlamellar regions, these latter modelled as soft interfaces. A multi-step homogenization procedure has been conceived and numerically applied to describe the equivalent mechanical response of osteon constituents, upscaling dominant subscale mechanisms. A progressive stress based damage approach has been implemented via a finite-element technique, allowing to describe interlaminar and/or intralaminar brittle failure modes. Proposed approach has been successfully validated by numerically reproducing available experimental tests of isolated osteons under different loading conditions. Present histologically-oriented multiscale model revealed to be sound and consistent, opening towards further insights about the influence on bone biomechanics of through-the-scales biophysical/biochemical alterations, possibly related to ageing or diseases
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