scholarly journals Orientation and size-dependent mechanical modulation within individual secondary osteons in cortical bone tissue

2013 ◽  
Vol 10 (81) ◽  
pp. 20120953 ◽  
Author(s):  
Davide Carnelli ◽  
Pasquale Vena ◽  
Ming Dao ◽  
Christine Ortiz ◽  
Roberto Contro
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Mechanical Behaviour ◽  
Long Bone ◽  
Periodic Pattern ◽  
Haversian Canal ◽  
Length Scale ◽  
Lamellar Bone ◽  
Mechanical Modulation ◽  
Secondary Osteons

Anisotropy is one of the most peculiar aspects of cortical bone mechanics; however, its anisotropic mechanical behaviour should be treated only with strict relationship to the length scale of investigation. In this study, we focus on quantifying the orientation and size dependence of the spatial mechanical modulation in individual secondary osteons of bovine cortical bone using nanoindentation. Tests were performed on the same osteonal structure in the axial (along the long bone axis) and transverse (normal to the long bone axis) directions along arrays going radially out from the Haversian canal at four different maximum depths on three secondary osteons. Results clearly show a periodic pattern of stiffness with spatial distance across the osteon. The effect of length scale on lamellar bone anisotropy and the critical length at which homogenization of the mechanical properties occurs were determined. Further, a laminate-composite-based analytical model was applied to the stiffness trends obtained at the highest spatial resolution to evaluate the elastic constants for a sub-layer of mineralized collagen fibrils within an osteonal lamella on the basis of the spatial arrangement of the fibrils. The hierarchical arrangement of lamellar bone is found to be a major determinant for modulation of mechanical properties and anisotropic mechanical behaviour of the tissue.

Mechanical Anisotropy of Individual Osteons in Bone Tissue at High Spatial Resolutions

2009 ◽  
Author(s):  
Davide Carnelli ◽  
Haimin Yao ◽  
Ming Dao ◽  
Pasquale Vena ◽  
Roberto Contro ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Mechanical Anisotropy ◽  
Haversian Canal ◽  
Maximum Penetration ◽  
Fundamental Units ◽  
Anisotropy Of Mechanical Properties ◽  
Penetration Depths ◽  
Secondary Osteons ◽  
Mineralized Collagen

Secondary osteons, the fundamental units of cortical bone, consist of cylindrical lamellar composites composed of mineralized collagen fibrils. Due to its lamellar structure, a multiscale knowledge of the mechanical properties of cortical bone is required to understand the biomechanical function of the tissue. In this light, nanoindentation tests were performed along the axial and transverse directions following a radial path from the Haversian canal to the osteonal edges. Different length scales are explored by means of indentations at different maximum penetration depths. Indentation moduli and hardness data were then interpreted in the context of the known microstructure. Results suggest that secondary osteons hierarchical structure is responsible for an observed length scale effect, homogenization phenomena and anisotropy of mechanical properties.

scholarly journals Osteology of a perinatal aristonectine (Plesiosauria; Elasmosauridae)

2016 ◽  
Vol 29 (1) ◽  
pp. 61-72 ◽  
Author(s):  
José P. O’Gorman ◽  
Marianella Talevi ◽  
Marta S. Fernández
Keyword(s):  
Cortical Bone ◽  
Bone Tissue ◽  
Endochondral Ossification ◽  
Morphological Changes ◽  
Relative Size ◽  
Lamellar Bone ◽  
Breeding Area ◽  
Primary Bone ◽  
Secondary Osteons ◽  
Seymour Island

AbstractPerinatal specimens give valuable information about the first stages of vertebrate ontogeny. Here, the morphology and palaeohistology of an aristonectine perinatal specimen from Seymour Island (Isla Marambio), López de Bertodano Formation are analysed. The palaeohistological analysis shows incomplete endochondral ossification (retention of a calcified cartilaginous core in the medullary region), predominance of primary bone tissue without secondary remodelling, lack of primary or secondary osteons and of growth marks in the cortical bone, and open vascular spaces not surrounded by a thin coat of lamellar bone tissue. General lines of morphological changes were inferred from comparing the fossil with an adult aristonectine specimen indicating i) a tendency of relatively high and broad posterior cervicals to decrease during ontogeny, ii) a decrease of relative size of the dorsolateral process and an increase of the glenoid ramus and iii) the existence of two separate stages in propodial growth divided into an initial elongation followed by a distal expansion. The presence of a perinatal specimen in the James Ross Archipelago indicates that the region was used as a breeding area by the aristonectines during the last part of the Cretaceous.

Elastic Anisotropy of Human Cortical Bone Secondary Osteons Measured by Nanoindentation

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Giampaolo Franzoso ◽  
Philippe K. Zysset
Keyword(s):  
Cortical Bone ◽  
Elastic Properties ◽  
Elastic Constants ◽  
Elastic Anisotropy ◽  
Elastic Model ◽  
Indentation Modulus ◽  
Lamellar Bone ◽  
Macroscopic Level ◽  
Human Cortical Bone ◽  
Secondary Osteons

The identification of anisotropic elastic properties of lamellar bone based on nanoindentation data is an open problem. Therefore, the purpose of this study was to develop a method to estimate the orthotropic elastic constants of human cortical bone secondary osteons using nanoindentation in two orthogonal directions. Since the indentation modulus depends on all elastic constants and, for anisotropic materials, also on the indentation direction, a theoretical model quantifying the indentation modulus from the stiffness tensor of a given material was implemented numerically (Swadener and Pharr, 2001, “Indentation of Elastically Anisotropic Half-Spaces by Cones and Parabolae of Revolution,” Philos. Mag. A, 81(2), pp. 447–466). Nanoindentation was performed on 22 osteons of the distal femoral shaft: A new holding system was designed in order to indent the same osteon in two orthogonal directions. To interpret the experimental results and identify orthotropic elastic constants, an inverse procedure was developed by using a fabric-based elastic model for lamellar bone. The experimental indentation moduli were found to vary with the indentation direction and showed a marked anisotropy. The estimated elastic constants showed different degrees of anisotropy among secondary osteons of the same bone and these degrees of anisotropy were also found to be different than the one of cortical bone at the macroscopic level. Using the log-Euclidean norm, the relative distance between the compliance tensors of the estimated mean osteon and of cortical bone at the macroscopic level was 9.69%: Secondary osteons appeared stiffer in their axial and circumferential material directions, and with a greater bulk modulus than cortical bone, which is attributed to the absence of vascular porosity in osteonal properties. The proposed method is suitable for identification of elastic constants from nanoindentation experiments and could be adapted to other (bio)materials, for which it is possible to describe elastic properties using a fabric-based model.

scholarly journals Evolution of the viscoelastic properties of painting stratigraphies: a moisture weathering and nanoindentation approach

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Mathilde Tiennot ◽  
Davide Iannuzzi ◽  
Erma Hermens
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Cultural Heritage ◽  
Mechanical Behaviour ◽  
Viscoelastic Properties ◽  
Viscoelastic Behaviour ◽  
Storage And Loss Moduli ◽  
Heritage Studies ◽  
Paint Films ◽  
The Impact

AbstractIn this investigation on the mechanical behaviour of paint films, we use a new ferrule-top nanoindentation protocol developed for cultural heritage studies to examine the impact of repeated relative humidity variations on the viscoelastic behaviour of paint films and their mechanical properties in different paint stratigraphies through the changes in their storage and loss moduli. We show that the moisture weathering impact on the micromechanics varies for each of these pigment-oil systems. Data from the nanoindentation protocol provide new insights into the evolution of the viscoelastic properties dsue to the impact of moisture weathering on paint films.

Research on Anisotropic Fracture Mechanical Behavior of Cortical Bone with Combined Method of Fractal and Gray Level Co-Occurrence Matrix

2021 ◽  
Vol 11 (1) ◽  
pp. 67-75
Author(s):  
Dagang Yin ◽  
Bin Chen ◽  
Huifen Zhou
Keyword(s):  
Mechanical Properties ◽  
Fracture Surface ◽  
Cortical Bone ◽  
Fracture Mechanisms ◽  
Gray Level ◽  
Combined Method ◽  
Characteristic Parameters ◽  
Fracture Surfaces ◽  
Anisotropic Fracture ◽  
Occurrence Matrix

The irregular fracture surface of cortical bone, which is caused by complex multilevel micro-nanostructure, reflects the mechanical properties and fracture mechanisms. It is of great significance to characterize some characteristic parameters from the fracture surfaces of bone. In this research, anisotropic fracture mechanical properties of bovine femoral cortical bone along transverse, longitudinal and radial direction are firstly obtained by three-point bend experiment. Then the fracture routes and fracture surfaces are observed by scanning electron microscope. The observation shows that the formed fracture surfaces, which are caused by different crack routes, are extremely rough and have complex textures. Lastly, the combined method of fractal and gray level co-occurrence matrix are adopted to describe the morphology of fracture surface of cortical bone objectively and quantitatively. It is shown that the fracture surface of cortical bone has obvious fractal characteristics and four statistical texture feature parameters (contrast,angular second moment, correlation and entropy) of GLCM of fracture surfaces can describe a certain fracture texture character. The relationship between the characteristic parameters and macroscopic mechanical properties are established. The quantitative analysis and automatic class identification for the fracture surfaces of cortical bone can be achieved.

scholarly journals Effect of the mechanical properties and mode loading on the mechanical behaviour of weldment: a numerical analysis

2013 ◽  
Vol 16 (4) ◽  
pp. 853-859 ◽  
Author(s):  
Meddah Hadj Miloud ◽  
Ould chikh Bahri ◽  
Benhamena Ali ◽  
Benguediab Mohamed ◽  
Bouchouicha Benattou
Keyword(s):  
Mechanical Properties ◽  
Numerical Analysis ◽  
Mechanical Behaviour

Tissue level mechanical properties of cortical bone in skeletally immature and mature dogs

2009 ◽  
Vol 22 (03) ◽  
pp. 210-215 ◽  
Author(s):  
C.A. Phillips ◽  
S.A. Fernandez ◽  
Y. Li ◽  
S.S. Huja
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Tissue Level ◽  
Mechanical Tests ◽  
Indentation Modulus ◽  
Skeletally Immature ◽  
Beagle Dogs ◽  
Cross Sectional ◽  
Specimen Holder ◽  
Immature Group

Summary Objectives: The purpose of this study was to quantify the tissue level mechanical properties of cortical bone of skeletally immature (~five-month-old) Beagle dogs and compare them to data from mature dogs measured in a previous study. Methods: Eight femoral cross sectional specimens (two bone sections / dog) were obtained from four skeletally immature dogs. A pair of calcein bone labels were administered intravenously to the dogs to mark sites of active mineralization prior to euthanasia. Prepared bone specimens were placed in a nanoindenter specimen holder and the previously identified calcein labelled osteons were located. Labelled (n = 128) and neighbouring unlabelled (n = 127) osteons in skeletally immature femurs were examined by instrumented indentation testing. Indents were made to a depth of 500 nm at a loading rate of 10 nm/s. Indentation modulus (IM) and hardness (H) were obtained. Results: The overall IM of the cortical bone in the skeletally mature groups was significantly greater than in the immature group (p = 0.0011), however overall H was not significantly different. The differences between the groups in IM were significant for the unlabelled osteons (p = 0.001), but not for the labelled osteons (p = 0.56). Conclusion: There are differences in the IM of unlabelled osteons in skeletally immature and mature groups of Beagle dogs. In contrast to whole bone mechanical tests, where there are obvious differences between growing and mature bones, there are only small differences in the micro-mechanical properties.

scholarly journals Atomistic investigation into the mechanical behaviour of crystalline and amorphous TiO2 nanotubes

RSC Advances ◽  
2016 ◽  
Vol 6 (33) ◽  
pp. 28121-28129 ◽  
Author(s):  
Yanan Xu ◽  
Mingchao Wang ◽  
Ning Hu ◽  
John Bell ◽  
Cheng Yan
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Titanium Dioxide ◽  
Molecular Dynamics Simulations ◽  
Mechanical Behaviour ◽  
Tio2 Nanotubes ◽  
Amorphous Tio2 ◽  
Dynamics Simulations

The mechanical properties of titanium dioxide (TiO2) nanotubes are studied based on molecular dynamics simulations.

The tensile behaviour of biaxial and triaxial braided fabrics

2016 ◽  
Vol 47 (8) ◽  
pp. 2184-2204 ◽  
Author(s):  
Duchamp Boris ◽  
Legrand Xavier ◽  
Soulat Damien
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Mechanical Behaviour ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Tensile Behaviour ◽  
Linear Mass ◽  
Double Peak ◽  
Specific Behaviour ◽  
Braiding Angle

The tensile behaviour of braid reinforcement is classically described by the behaviour of composite elaborated from these reinforcements. Few studies concern the tensile behaviour of braided fabrics. In this paper biaxial and triaxial braids are manufactured on a braiding loom. The evolution of key parameters as linear mass and braiding angle in function of process parameters is presented. Braid reinforcements are characterized in uniaxial tensile. The mechanical behaviour is analysed and compared in function of the braiding angle, but also different kinds of braid are considered. A specific behaviour called “double-peak” is identified for triaxial braids which have a higher braiding angle. The evolution of the braiding angle measured during tensile tests gives a comprehension on the mechanical behaviour of dry braids. Associated with this experimental study, an analytical model is also proposed, to predict mechanical properties of braid reinforcements.

Effects of dynamic indentation on the mechanical response of materials

2008 ◽  
Vol 23 (6) ◽  
pp. 1604-1613 ◽  
Author(s):  
M.J. Cordill ◽  
N.R. Moody ◽  
W.W. Gerberich
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Mechanical Response ◽  
Length Scale ◽  
Polycrystalline Nickel ◽  
Dynamic Indentation ◽  
Crystalline Materials ◽  
Fused Quartz ◽  
Hardness Values ◽  
Measured Hardness

Dynamic indentation techniques are often used to determine mechanical properties as a function of depth by continuously measuring the stiffness of a material. The dynamics are used by superimposing an oscillation on top of the monotonic loading. Of interest was how the oscillation affects the measured mechanical properties when compared to a quasi-static indent run at the same loading conditions as a dynamic. Single crystals of nickel and NaCl as well as a polycrystalline nickel sample and amorphous fused quartz and polycarbonate have all been studied. With respect to dynamic oscillations, the result is a decrease of the load at the same displacement and thus lower measured hardness values of the ductile crystalline materials. It has also been found that the first 100 nm of displacement are the most affected by the oscillating tip, an important length scale for testing thin films, nanopillars, and nanoparticles.

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