Numerical simulations of 3D open cell structures – influence of structural irregularities on elasto-plasticity and deformation localization

Luxner, Mathias H.; Stampfl, Juergen; Pettermann, H.E.

doi:10.1016/j.ijsolstr.2006.08.039

Cited by 104 publications

(58 citation statements)

References 28 publications

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“…In the disordered structures, load was unevenly redistributed and this prevented the formation of localized regions with yielded trabeculae. This finding is in agreement with previous works on cellular structures (Luxner et al 2007(Luxner et al , 2009. It should be mentioned that a secondary effect of increasing disorder was an increase in the relative density of the lattice due to an increase in the average length of individual trabeculae.…”

Section: (C) (D)supporting

confidence: 93%

Mechanisms of reduced implant stability in osteoporotic bone

Ruffoni

Müller

Lenthe

2011

Biomech Model Mechanobiol

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The determining factors for the fixation of uncemented screws in bone are the bone-implant interface and the peri-implant bone. The goal of this work was to explore the role of the peri-implant bone architecture on the mechanics of the bone-implant system. In particular, the specific aims of the study were to investigate: (i) the impact of the different architectural parameters, (ii) the effects of disorder, and (iii) the deformations in the peri-implant region. A three-dimensional beam lattice model to describe trabecular bone was developed. Various microstructural features of the lattice were varied in a systematic way. Implant pull-out tests were simulated, and the stiffness and strength of the bone-implant system were computed. The results indicated that the strongest decrease in pull-out strength was obtained by trabecular thinning, whereas pull-out stiffness was mostly affected by trabecular removal. These findings could be explained by investigating the peri-implant deformation field. For small implant displacements, a large amount of trabeculae in the peri-implant region were involved in the load transfer from implant to bone. Therefore, trabecular removal in this region had a strong negative effect on pull-out stiffness. Conversely, at higher displacements, deformations mainly localized in the trabeculae in contact with the implant; hence, thinning those trabeculae produced the strongest decrease in the strength of the system. Although idealized, the current approach is helpful for a mechanical understanding of the role played by peri-implant bone.

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Section: (C) (D)supporting

confidence: 93%

Mechanisms of reduced implant stability in osteoporotic bone

Ruffoni

Müller

Lenthe

2011

Biomech Model Mechanobiol

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“…Luxner et al [29] studied how the energy is distributed in different struts of a 3D open cell structure when loaded uniaxially by looking at frequency distributions of the energy. In cases of a small irregularity of the structure, the distribution was sharply peaked, indicating a concentration of the strain energy in few sites of the cellular solid [29].…”

Section: Introductionmentioning

confidence: 99%

Effect of minimal defects in periodic cellular solids

Ruffoni

Dunlop

Fratzl

et al. 2010

Philosophical Magazine

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We study the relationship between the geometry of a point defect and the spatial distribution of the strain energy in an otherwise regular two-dimensional cellular solid. Sites of concentrated strain energy are potential sites for failure initiation in the cellular solid. For simplicity, a hexagonal honeycomb structure is chosen for our analysis. In our description, the basic building block of the honeycomb is not a beam, but rather a three-armed ''joint'', with the three beams meeting at a junction point. A minimal defect is introduced in an otherwise regular hexagonal honeycomb by exchanging one joint of the regular honeycomb with a joint of varying geometry. Finite element methods and micromechanical models are used to calculate the spatial distribution of the strain energy density (SED). Two different scenarios are found depending on the external loading. For hydrostatic loading, the SED is concentrated in the defect. Uniaxial loading resulted in intricate distribution of the SED, with its highest values not in the defect but in the nearer environment of the defect. The study demonstrates the complexity of SED patterns occurring around defects, which change their characteristics depending on the loading conditions.

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“…In [14 and 15], FEM is used to predict the linear and nonlinear mechanical behavior of open cell foams under compressive loads. Studies on the overall nonlinear response of regular and disordered simple cubic and Kelvin structures are presented in [16,17].…”

Section: Introductionmentioning

confidence: 99%