Directional Tortuosity as a Predictor of Modulus Damage for Vertebral Cancellous Bone

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
David P. Fyhrie ◽  
Roger Zauel
Keyword(s):  
Mechanical Properties ◽  
Cancellous Bone ◽  
Volume Fraction ◽  
Compressive Strain ◽  
Effective Modulus ◽  
Hard Tissue ◽  
Bone Volume Fraction ◽  
Tissue Microstructure ◽  
Induced Changes ◽  
Effective Mechanical Properties

There are many methods used to estimate the undamaged effective (apparent) moduli of cancellous bone as a function of bone volume fraction (BV/TV), mean intercept length (MIL), and other image based average microstructural measures. The MIL and BV/TV are both only functions of the cancellous microstructure and, therefore, cannot directly account for damage induced changes in the intrinsic trabecular hard tissue mechanical properties. Using a nonlinear finite element (FE) approximation for the degradation of effective modulus as a function of applied effective compressive strain, we demonstrate that a measurement of the directional tortuosity of undamaged trabecular hard tissue strongly predicts directional effective modulus (r2 > 0.90) and directional effective modulus degradation (r2 > 0.65). This novel measure of cancellous bone directional tortuosity has the potential for development into an anisotropic approach for calculating effective mechanical properties as a function of trabecular level material damage applicable to understanding how tissue microstructure and intrinsic hard tissue moduli interact to determine cancellous bone quality.

Misalignment Error in Cancellous Bone Apparent Elastic Modulus Depends on Bone Volume Fraction and Degree of Anisotropy

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Matthew B. L. Bennison ◽  
A. Keith Pilkey ◽  
W. Brent Lievers
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Cancellous Bone ◽  
Volume Fraction ◽  
Experimental Studies ◽  
Bone Volume ◽  
Bone Volume Fraction ◽  
Skeletal Site ◽  
Degree Of Anisotropy ◽  
Misalignment Error

Abstract Cancellous bone is an anisotropic structure with architectural and mechanical properties that vary due to both skeletal site and disease state. This anisotropy means that, in order to accurately and consistently measure the mechanical properties of cancellous bone, experiments should be performed along the primary mechanical axis (PMA), that is, the orientation in which the mechanical properties are at their maximum value. Unfortunately, some degree of misalignment will always be present, and the magnitude of the resulting error is expected to be architecture dependent. The goal of this work is to quantify the dependence of the misalignment error, expressed in terms of change in apparent elastic modulus (ΔE), on both the bone volume fraction (BV/TV) and the degree of anisotropy (DA). Finite element method (FEM) models of bovine cancellous bone from five different skeletal sites were created at 5 deg and 20 deg from the PMA determined for each region. An additional set of models was created using image dilation/erosion steps in order to control for BV/TV and better isolate the effect of DA. Misalignment error was found to increase with increasing DA and decreasing BV/TV. At 5 deg misaligned from the PMA, error is relatively low (<5%) in all cases but increases to 8–24% error at 20 deg. These results suggest that great care is needed to avoid introducing misalignment error into experimental studies, particularly when studying regions with high anisotropy and/or low bone volume fraction, such as vertebral or osteoporotic bone.

Prediction of Mechanical Properties of the Cancellous Bone of the Mandibular Condyle

2003 ◽  
Vol 82 (10) ◽  
pp. 819-823 ◽  
Author(s):  
L.J. van Ruijven ◽  
E.B.W. Giesen ◽  
M. Farella ◽  
T.M.G.J. van Eijden
Keyword(s):  
Mechanical Properties ◽  
Cancellous Bone ◽  
Volume Fraction ◽  
Bone Structure ◽  
Structural Parameters ◽  
Mandibular Condyle ◽  
Element Model ◽  
Micro Computed Tomography ◽  
Bone Volume Fraction ◽  
Apparent Stiffness

The mechanical properties of cancellous bone depend on the bone structure. The present study examined the extent to which the apparent stiffness of the cancellous bone of the human mandibular condyle can be predicted from its structure. Two models were compared. The first, a structure model, used structural parameters such as bone volume fraction and anisotropy to estimate the apparent stiffness. The second was a finite element model (FEM) of the cancellous bone. The bone structure was characterized by micro-computed tomography. The calculated stiffnesses of 24 bone samples were compared with measured stiffnesses. Both models could predict 89% of the variation in the measured stiffnesses. From the stiffness approximated by FEM in combination with the measured stiffness, the stiffness of the bone tissue was estimated to be 11.1 ± 3.2 GPa. It was concluded that both models could predict the stiffness of cancellous bone with adequate accuracy.

Changed Morphology and Mechanical Properties of Cancellous Bone in the Mandibular Condyles of Edentate People

2004 ◽  
Vol 83 (3) ◽  
pp. 255-259 ◽  
Author(s):  
E.B.W. Giesen ◽  
M. Ding ◽  
M. Dalstra ◽  
T.M.G.J. van Eijden
Keyword(s):  
Mechanical Properties ◽  
Cancellous Bone ◽  
Regression Models ◽  
Volume Fraction ◽  
Mechanical Load ◽  
Micro Computed Tomography ◽  
Bone Morphology ◽  
Bone Volume Fraction ◽  
Fundamental Relationship ◽  
Morphology And Mechanical Properties

Since edentate subjects have a reduced masticatory function, it can be expected that the morphology of the cancellous bone of their mandibular condyles has changed according to the altered mechanical environment. In the present study, the morphology of cylindrical cancellous bone specimens of the mandibular condyles of edentate subjects (n = 25) was compared with that of dentate subjects (n = 24) by means of micro-computed tomography and by the application of Archimedes’ principle. Stiffness and strength were determined by destructive mechanical testing. Compared with dentate subjects, it appeared that, in edentate subjects, the bone was less dense and the trabecular structure was less plate-like. The regression models of stiffness and strength built from bone volume fraction and the trabecular orientation relative to the axis of the specimen were similar for both dentate and edentate subjects. This indicates that, under reduced mechanical load, the fundamental relationship between bone morphology and mechanical properties does not change.

scholarly journals Bone health in spacefaring rodents and primates: systematic review and meta-analysis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jingyan Fu ◽  
Matthew Goldsmith ◽  
Sequoia D. Crooks ◽  
Sean F. Condon ◽  
Martin Morris ◽  
...  
Keyword(s):  
Bone Formation ◽  
Trabecular Bone ◽  
Bone Health ◽  
Volume Fraction ◽  
Meta Analysis ◽  
Bone Volume ◽  
Trabecular Bone Volume ◽  
Bone Volume Fraction ◽  
Percentage Difference ◽  
Induced Changes

AbstractAnimals in space exploration studies serve both as a model for human physiology and as a means to understand the physiological effects of microgravity. To quantify the microgravity-induced changes to bone health in animals, we systematically searched Medline, Embase, Web of Science, BIOSIS, and NASA Technical reports. We selected 40 papers focusing on the bone health of 95 rats, 61 mice, and 9 rhesus monkeys from 22 space missions. The percentage difference from ground control in rodents was –24.1% [Confidence interval: −43.4, −4.9] for trabecular bone volume fraction and –5.9% [−8.0, −3.8] for the cortical area. In primates, trabecular bone volume fraction was lower by –25.2% [−35.6, −14.7] in spaceflight animals compared to GC. Bone formation indices in rodent trabecular and cortical bone were significantly lower in microgravity. In contrast, osteoclast numbers were not affected in rats and were variably affected in mice. Thus, microgravity induces bone deficits in rodents and primates likely through the suppression of bone formation.

scholarly journals Comparative finite-element analysis: a single computational modelling method can estimate the mechanical properties of porcine and human vertebrae

2014 ◽  
Vol 11 (95) ◽  
pp. 20140186 ◽  
Author(s):  
K. Robson Brown ◽  
S. Tarsuslugil ◽  
V. N. Wijayathunga ◽  
R. K. Wilcox
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Model Development ◽  
Computational Modelling ◽  
Bone Volume Fraction ◽  
Element Analysis ◽  
Modelling Method ◽  
Modelling Techniques ◽  
Musculoskeletal Systems ◽  
Development And Validation

Significant advances in the functional analysis of musculoskeletal systems require the development of modelling techniques with improved focus, accuracy and validity. This need is particularly visible in the fields, such as palaeontology, where unobservable parameters may lie at the heart of the most interesting research questions, and where models and simulations may provide some of the most innovative solutions. Here, we report on the development of a computational modelling method to generate estimates of the mechanical properties of vertebral bone across two living species, using elderly human and juvenile porcine specimens as cases with very different levels of bone volume fraction and mineralization. This study is presented in two parts; part I presents the computational model development and validation, and part II the virtual loading regime and results. This work paves the way for the future estimation of mechanical properties in fossil mammalian bone.

Structural and Mechanical Properties of Mandibular Condylar Bone

2006 ◽  
Vol 85 (1) ◽  
pp. 33-37 ◽  
Author(s):  
T.M.G.J. van Eijden ◽  
P.N. van der Helm ◽  
L.J. van Ruijven ◽  
L. Mulder
Keyword(s):  
Mechanical Properties ◽  
Elastic Moduli ◽  
Volume Fraction ◽  
Sagittal Plane ◽  
Mandibular Condyle ◽  
Mechanical Anisotropy ◽  
Bone Volume Fraction ◽  
Shear Moduli ◽  
Trabecular Density ◽  
Ct System

The trabecular bone of the mandibular condyle is structurally anisotropic and heterogeneous. We hypothesized that its apparent elastic moduli are also anisotropic and heterogeneous, and depend on trabecular density and orientation. Eleven condyles were scanned with a micro-CT system. Volumes of interest were selected for the construction of finite element models. We simulated compressive and shear tests to determine the principal mechanical directions and the apparent elastic moduli. Compressive moduli were relatively large in directions acting in the sagittal plane, and small in the mediolateral direction. The degree of mechanical anisotropy ranged from 4.7 to 10.8. Shear moduli were largest in the sagittal plane and smallest in the transverse plane. The magnitudes of the moduli varied with the condylar region and were proportional to the bone volume fraction. Furthermore, principal mechanical direction correlated significantly with principal structural direction. It was concluded that variation in trabecular structure coincides with variation in apparent mechanical properties.

Combination of topological parameters and bone volume fraction better predicts the mechanical properties of trabecular bone

2002 ◽  
Vol 35 (8) ◽  
pp. 1091-1099 ◽  
Author(s):  
Laurent Pothuaud ◽  
Bert Van Rietbergen ◽  
Lis Mosekilde ◽  
Olivier Beuf ◽  
Pierre Levitz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Trabecular Bone ◽  
Volume Fraction ◽  
Bone Volume ◽  
Bone Volume Fraction ◽  
Topological Parameters

scholarly journals Structure-Function Relationships of the Vertebral Endplate

2021 ◽  
Author(s):  
Yuanqiao Wu ◽  
Elise Feng-i Morgan ◽  
Johnfredy Loaiza ◽  
Rohin Banerji ◽  
Olivia Rose Blouin
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Yield Stress ◽  
Volume Fraction ◽  
Level Density ◽  
Micro Computed Tomography ◽  
Vertebral Endplate ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Apparent Stiffness

Background: Although deformation and fracture of the vertebral endplate have been implicated in spinal conditions such as vertebral fracture and disc degeneration, few biomechanical studies of this structure are available. The goal of this study was to quantify the mechanical behavior of the vertebral endplate. Methods: Eight-five rectangular specimens were dissected from the superior and/or inferior central endplates of human lumbar spine segments L1-L4. Micro-computed tomography (μCT) imaging, four-point-bend testing, and ashing were performed to quantify the apparent elastic modulus and yield stress (modulus and yield stress, respectively, of the porous vertebral endplate), tissue yield stress (yield stress of the tissue of the vertebral endplate, excluding pores), ultimate strain, fracture strain, bone volume fraction (BV/TV), bone mineral density (BMD), and various measures of tissue density and composition (tissue mineral density, ash fraction, and ash density). Regression was used to assess the dependence of mechanical properties on density and composition. Results: Wide variations in elastic and failure properties, and in density and tissue composition, were observed. BMD and BV/TV were good predictors of many of the apparent-level mechanical properties, including modulus, yield stress, and in the case of the inferior vertebral endplate, failure strains. Similar values of the mechanical properties were noted between superior and inferior vertebral endplates. In contrast to the dependence of apparent stiffness and strength on BMD and BV/TV, none of the mechanical properties depended on any of the tissue-level density measurements. Conclusion: The dependence of many of the mechanical properties of the vertebral endplate on BV/TV and BMD suggests possibilities for non-invasive assessment of how this region of the spine behaves during habitual and injurious loading. Further study of the non-mineral components of the endplate tissue is required to understand how the composition of this tissue may influence the overall mechanical behavior of the vertebral endplate.

scholarly journals Effective Mechanical Property Estimation of Composite Solid Propellants Based on VCFEM

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Liu-Lei Shen ◽  
Zhi-Bin Shen ◽  
Yan Xie ◽  
Hai-Yang Li
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Structural Integrity ◽  
Volume Fraction ◽  
Solid Rocket Motor ◽  
Critical Material ◽  
Composite Solid ◽  
Effective Mechanical Properties ◽  
Element Method

A solid rocket motor is one of the critical components of solid missiles, and its life and reliability mostly depend on the mechanical behavior of a composite solid propellant (CSP). Effective mechanical properties are critical material constants to analyze the structural integrity of propellant grain. They are estimated by a numerical method that combines the Voronoi cell finite element method (VCFEM) and the homogenization method in the present paper. The correctness of this combined method has been validated by comparing with a standard finite element method and conventional theoretical models. The effective modulus and the effective Poisson’s ratio of a CSP varying with volume fraction and component material properties are estimated. The result indicates that the variations of the volume fraction of inclusions and the properties of the matrix have obvious influences on the effective mechanical properties of a CSP. The microscopic numerical analysis method proposed in this paper can also be used to provide references for the design and the analysis of other large volume fraction composite materials.

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