Effect of Bone Mineral Content on the Tensile Properties of Cortical Bone: Experiments and Theory

2003 ◽  
Vol 125 (6) ◽  
pp. 785-793 ◽  
Author(s):  
S. P. Kotha ◽  
N. Guzelsu
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Bone Mineral Content ◽  
Cortical Bone ◽  
Yield Stress ◽  
Bone Tissue ◽  
Bone Mineral ◽  
Mineral Content ◽  
Organic Matrix ◽  
Experimental Values

The effect of mineral volume fraction on the tensile mechanical properties of cortical bone tissue is investigated by theoretical and experimental means. The mineral content of plexiform, bovine bone was lowered by 18% and 29% by immersion in fluoride solutions for 3 days and 12 days, respectively. The elastic modulus, yield strength and ultimate strength of bone tissue decreased, while the ultimate strain increased with a decrease in mineral content. The mechanical behavior of bone tissue was modeled by using a micro-mechanical shear lag theory consisting of overlapped mineral platelets reinforcing the organic matrix. The decrease in yield stress, by the 0.002 offset method, of the fluoride treated bones were matched in the theoretical curves by lowering the shear yield stress of the organic matrix. The failure criterion used was based on failure stresses determined from a failure envelope (Mohr’s circle), which was constructed using experimental data. It was found that the model predictions of elastic modulus got worse with a decrease in mineral content (being 7.9%, 17.2% and 33.0% higher for the control, 3-day and 12-day fluoride-treated bones). As a result, the developed theory could not fully predict the yield strain of bones with lowered mineral content, being 12.9% and 21.7% lower than the experimental values. The predicted ultimate stresses of the bone tissues with lower mineral contents were within ±10% of the experimental values while the ultimate strains were 12.7% and 26.3% lower than the experimental values. Although the model developed in this study did not take into account the presence of hierarchical structures, voids, orientation of collagen molecules and micro cracks, it still indicated that the mechanical properties of the organic matrix depend on bone mineral content.

scholarly journals Kearns texture parameters, mechanical properties and damageability of titanium sheet after alternating bending

2021 ◽  
Vol 22 (3) ◽  
pp. 543-550
Author(s):  
V.V. Usov ◽  
N.M. Shkatulyak ◽  
O.S. Savchuk ◽  
N.I. Rybak
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Ultimate Tensile Strength ◽  
Yield Stress ◽  
Rolling Direction ◽  
Initial State ◽  
Texture Parameters ◽  
Experimental Values ◽  
Alternating Bending

This work aims to determine the Kearns texture parameters and evaluate on their basis the elastic moduli, mechanical properties (ultimate tensile strength, conditional yield stress), as well as damageability parameters of the sheets commercial titanium (CT-grade 1: 0.04% Fe; 0.015% C; 0.05% N 0.05% c; 0.009% H)  as delivered after rolling and annealing at 840°C (original sheet) and further alternating bending (AB) in the amount of 0.5; 1, 3 and 5 cycles. Damageability parameters characterizing damage accumulation were determined from the elastic modulus change after the above-mentioned number of AB cycles relative to the values ​​of the elastic modulus in different directions of the original sheet of the studied titanium. The elastic constants of the single crystal and the Kearns texture parameters were used to estimate the elastic modulus in the rolling direction (RD) and transverse direction (TD) of the original sheet, and sheets after an above number of AB cycles. The deviation of the calculated and experimental values ​​of the elastic modulus did not exceed 5%. The deviation of the calculated and experimental values of the ultimate tensile strength and yield stress in the RD and TD both in the initial state and after the corresponding number cycles of the AB did not exceed 10%.

scholarly journals Analysis of Mechanical Properties and Mechanical Anisotropy in Canine Bone Tissues of Various Ages

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Changqi Luo ◽  
Junyi Liao ◽  
Zhenglin Zhu ◽  
Xiaoyu Wang ◽  
Xiao Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Cortical Bone ◽  
Bone Tissue ◽  
Poisson Ratio ◽  
Age Groups ◽  
Distal Region ◽  
Mechanical Anisotropy ◽  
Age Group ◽  
Cross Sectional

The effect of age on mechanical behavior and microstructure anisotropy of bone is often ignored by researchers engaged in the study of biomechanics. The objective of our study was to determine the variations in mechanical properties of canine femoral cortical bone with age and the mechanical anisotropy between the longitudinal and transverse directions. Twelve beagles divided into three age groups (6, 12, and 36 months) were sacrificed and all femurs were extracted. The longitudinal and transverse samples of cortical bone were harvested from three regions of diaphysis (proximal, central, and distal). A nanoindentation technique was used for simultaneously measuring force and displacement of a diamond tip pressed 2000nm into the hydrated bone tissue. An elastic modulus was calculated from the unloading curve with an assumed Poisson ratio of 0.3, while hardness was defined as the maximal force divided by the corresponding contact area. The mechanical properties of cortical bone were determined from 852 indents on two orthogonal cross-sectional surfaces. Mean elastic modulus ranged from 7.56±0.32 GPa up to 21.56±2.35 GPa, while mean hardness ranged from 0.28±0.057 GPa up to 0.84±0.072 GPa. Mechanical properties of canine femoral cortical bone tended to increase with age, but the magnitudes of these increase for each region might be different. The longitudinal mechanical properties were significantly higher than that of transverse direction (P<0.01). A significant anisotropy was found in the mechanical properties while there was no significant correlation between the two orthogonal directions in each age group (r2<0.3). Beyond that, the longitudinal mechanical properties of the distal region in each age group were lower than the proximal and central regions. Hence, mechanical properties in nanostructure of bone tissue must differ mainly among age, sample direction, anatomical sites, and individuals. These results may help a number of researchers develop more accurate constitutive micromechanics models of bone tissue in future studies.

Intramedullary Nailing and Cortical Bone Mineral Content

1993 ◽  
Vol 34 (5) ◽  
pp. 464-467 ◽  
Author(s):  
Esko Kaartinen ◽  
L. Keskisaari ◽  
T. Holmström
Keyword(s):  
Bone Mineral Content ◽  
Cortical Bone ◽  
Intramedullary Nailing ◽  
Bone Mineral ◽  
Mineral Content

Altitude, pasture type, and sheep breed affect bone metabolism and serum 25-hydroxyvitamin D in grazing lambs

2013 ◽  
Vol 114 (10) ◽  
pp. 1441-1450 ◽  
Author(s):  
Helen Willems ◽  
Florian Leiber ◽  
Martina Kohler ◽  
Michael Kreuzer ◽  
Annette Liesegang
Keyword(s):  
Bone Mineral Content ◽  
Bone Metabolism ◽  
Cortical Bone ◽  
Bone Mineral ◽  
Mineral Content ◽  
Mineral Density ◽  
Hydroxyvitamin D ◽  
Alpine Pastures ◽  
25 Hydroxyvitamin D ◽  
Ca:P Ratio

This study aimed to investigate the bone development of two mountain sheep breeds during natural summer grazing either in the lowlands or on different characteristic alpine pastures. Pasture types differed in topographic slope, plant species composition, general nutritional feeding value, Ca and P content, and Ca:P ratio of herbage. Twenty-seven Engadine sheep (ES) lambs and 27 Valaisian Black Nose sheep (VS) lambs were divided into four groups of 6 to 7 animals per breed and allocated to three contrasting alpine pasture types and one lowland pasture type. The lambs were slaughtered after 9 wk of experimental grazing. The steep alpine pastures in combination with a high (4.8) to very high (13.6) Ca:P ratio in the forage decreased total bone mineral content as measured in the middle of the left metatarsus of the lambs from both breeds, and cortical bone mineral content and cortical bone mineral density of ES lambs. Breed × pasture type interactions occurred in the development of total and cortical bone mineral content, and in cortical thickness, indicating that bone metabolism of different genotypes obviously profited differently from the varying conditions. An altitude effect occurred for 25-hydroxyvitamin D with notably higher serum concentrations on the three alpine sites, and a breed effect led to higher concentrations for ES than VS. Despite a high variance, there were pasture-type effects on serum markers of bone formation and resorption.

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