Mechanical behaviour of staggered array of mineralised collagen fibrils in protein matrix: Effects of fibril dimensions and failure energy in protein matrix

Lai, Zheng Bo; Chen, Yan

doi:10.1016/j.jmbbm.2016.08.024

Cited by 28 publications

(8 citation statements)

References 42 publications

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“…Indeed, the cortical bone is a dense connective tissue consisting of dense and hard concentric layers called lamellae [31,57]. Each single lamella consists of mineralized collagen fibrils, a soft and ductile collagen fibrils reinforced with stiff hydroxyapatite crystals [35,40,70]. In each single lamella, the mineralized collagen fibrils, considered as the primary building block of bone [30], are oriented in one direction and rotate relative to the adjacent lamella [73].…”

Section: Numerical Resultsmentioning

confidence: 99%

Application of the Johnson-Cook plasticity model in the finite element simulations of the nanoindentation of the cortical bone.

Remache

Semaan

Rossi

et al. 2020

Journal of the Mechanical Behavior of Biomedical Materials

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The mechanical behavior of the cortical bone in nanoindentation is a complicated mechanical problem. The finite element analysis has commonly been assumed to be the most appropriate approach to this issue. One significant problem in nanoindentation modeling of the elastic-plastic materials is pileup deformation, which is not observed in cortical bone nanoindentation testing. This phenomenon depends on the work-hardening of materials; it doesn't occur for work-hardening materials, which suggests that the cortical bone could be considered as a work-hardening material. Furthermore, in a recent study [59], a plastic hardening until failure was observed on the micro-scale of a dry ovine osteonal bone samples subjected to micropillar compression. The purpose of the current study was to apply an isotropic hardening model in the finite element simulations of the nanoindentation of the cortical bone to predict its mechanical behavior. The Johnson-Cook (JC) model was chosen as the constitutive model. The finite element modeling in combination with numerical optimization was used to identify the unknown material constants and then the finite element solutions were compared to the experimental results. A good agreement of the numerical curves with the target loading curves was found and no pileup was predicted. A Design Of Experiments (DOE) approach was performed to evaluate the linear effects of the material constants on the mechanical response of the material. The strain hardening modulus and the strain hardening exponent were the most influential parameters. While a positive effect was noticed with the Young's modulus, the initial yield stress and the strain hardening modulus, an opposite 1 effect was found with the Poisson's ratio and the strain hardening exponent. Finally, the JC model showed a good capability to describe the elastoplastic behavior of the cortical bone.

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Section: Numerical Resultsmentioning

confidence: 99%

Application of the Johnson-Cook plasticity model in the finite element simulations of the nanoindentation of the cortical bone.

Remache

Semaan

Rossi

et al. 2020

Journal of the Mechanical Behavior of Biomedical Materials

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“…They found that the mesh size of cohesive elements had a significant effect on the strength of the mineralized fibrils. A recent study 46 investigated the evolution of damage in staggered array of mineralized collagen fibrils (MCF) embedded in extrafibrillar protein matrix modeled by continuum cohesive finite elements. The authors found that the failure mechanisms of the extrafibrillar matrix play a dominant role on the energy dissipation capacity of the system.…”

Section: Discussionmentioning

confidence: 99%

“…Our main assumptions are to neglect the material properties of the interfibrillar matrix and to consider the fibrils linked by cohesive surfaces whose damage process occurs in terms of stiffness degradation. Previously, cohesive behaviors were used for studying the damage mechanisms of bone at different scales. − Our approach, on the contrary, is based on cohesive stiffness representative of interfaces with negligible small thicknesses. The main difference between the two approaches is that in surface-based laws the damage evolution describes the degradation of the cohesive stiffness whereas in the continuum-based approach − the damage concerns the degradation of the material stiffness.…”

Section: Discussion and Conclusionmentioning

confidence: 99%

Staggered Fibrils and Damageable Interfaces Lead Concurrently and Independently to Hysteretic Energy Absorption and Inhomogeneous Strain Fields in Cyclically Loaded Antler Bone

Falco

Barbieri

Pugno

et al. 2017

ACS Biomater. Sci. Eng.

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The high toughness and work to fracture of hierarchical composites, like antler bone, involve structural 13 mechanisms at the molecular, nano-and micro scales, which are not completely explored. A key 14 characteristic of the high energy absorption of such materials is the large hysteresis during cyclic loading, but 15 its origin remains unknown. In situ synchrotron X-ray diffraction tests during tensile loading of antler bone 16 showed heterogeneous fibrillar deformation and hysteresis. To explain the origin of these mechanisms from 17 the nanostructure of antler bone, here we develop a class of finite-element fibril models whose predictions 18 are compared to experimental data across a range of potential composite architectures. We demonstrate 19 that the key structural motif enabling a match to experimental data is an axially staggered arrangement of 20 stiff mineralized collagen fibrils coupled with weak, damageable interfibrillar interfaces. 21 22 between structural properties at different scales 3. Bio-composites, such as bone, shells 29 and nacre, represent an excellent example of how the design at lower hierarchical scales 30 confers higher mechanical properties than the single constituents 4. Although the stiffness 31 of these biocomposites is comparable to that of the basic constituent at the nanoscale, 32 their toughness results hugely increased. For instance, in bone and shell, the toughness of 33 the mineral constituents is << 1MPa*m 1/2 while the toughness of their macrostructure 34 varies, respectively, in a range of 2-7 MPa*m 1/2 and 3-7 MPa*m 1/2. 35 36 Bone, as shown in Figure 1, at the nanometre scale length is a composite of stiff inorganic 37 hydroxyapatite platelets interleaved with a softer organic matrix, made principally of type I 38 tropocollagen proteins 5. This sub-structure, together with an intrafibrillar phase of 39 noncollageneous proteins and mineral, forms mineralized fibrils that are arranged into 40 aggregate structures at higher levels and larger length scales, such as fibril arrays and 41 lamellae 1. The structural aspects of this architecture served as inspiration for bioinspired 42 materials that replicate the nanometre scale fibril-matrix 6-10 and intrafibrillar 11 structure, or 43 at micrometre scales 12,13. Nonetheless, the mechanical interactions between the 44 constituent units and the higher length scales remain a matter of active research. In 45 particular, previous studies focused on how the hierarchical architecture brings functionally 46 desirable properties such as high toughness 14 , energy absorption and fatigue resistance 15. 47

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“…Thus, CF and its derivatives have incomparable biocompatibility, which has allowed their application in prosthesis, artificial tissue, drug carrier, food and cosmetics [10][11][12]. Furthermore, CF has the features of special microstructure, good mechanical strength, resistance to enzymatic cleavage and unavailability for most microorganisms [10,11,13,14]. Therefore, CF has a great potential application as a biocompatible support material for microbial immobilization.…”

Section: Introductionmentioning

confidence: 99%

Immobilization of Saccharomyces cerevisiae using polyethyleneimine grafted collagen fibre as support and investigations of its fermentation performance

Zhu

Liao

et al. 2017

Biotechnology & Biotechnological Equipment

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In the present investigation, an collagen fibre (CF), abundant natural biomass, was successfully grafted by polyethyleneimine (PEI). The resultant PEI grafted collagen fibre (CF-PEI) was employed as biocompatible and high cell loading support matrix for the immobilization of Saccharomyces cerevisiae cells. The as-prepared CF-PEI immobilized cells (CF-PEI-cell) exhibited high activity and stability for both batch and continuous fermentation. In batch fermentation, CF-PEI-cells showed enhanced stability as compared with other matrices supported cells, and produced an average ethanol concentration of 45.04 g/L with ethanol yield (Y P/S) of 0.46 g/g and glucose conversion efficiency (h) of 90.4%. Continuous fermentation was operated stably in a down-flow trickling bed reactor charged with CF-PEI-cell for a total of 2 months. When the dilution rate was 0.16 1/h, the average ethanol productivity reached 7.18 g/(L h) with h of 88.94%. Further scanning electron microscopy observations confirmed that yeast cells can proliferate on the surface of CF-PEI during ethanol fermentation, which demonstrates that CF-PEI is indeed an ideal matrix for the immobilization of yeast cells.

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Mechanical behaviour of staggered array of mineralised collagen fibrils in protein matrix: Effects of fibril dimensions and failure energy in protein matrix

Cited by 28 publications

References 42 publications

Application of the Johnson-Cook plasticity model in the finite element simulations of the nanoindentation of the cortical bone.

Application of the Johnson-Cook plasticity model in the finite element simulations of the nanoindentation of the cortical bone.

Staggered Fibrils and Damageable Interfaces Lead Concurrently and Independently to Hysteretic Energy Absorption and Inhomogeneous Strain Fields in Cyclically Loaded Antler Bone

Immobilization of Saccharomyces cerevisiae using polyethyleneimine grafted collagen fibre as support and investigations of its fermentation performance

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