Finite Element Analysis Demonstrates Splinting in the Porcine Mandibular Condyle Causes Changes in Bone Volume Fraction and Stiffness Anisotropy

2012 ◽  
Author(s):  
William Zaylor ◽  
Betty Sindelar ◽  
John R. Cotton
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Volume Fraction ◽  
Mandibular Condyle ◽  
Signs And Symptoms ◽  
Bone Volume ◽  
Bone Volume Fraction ◽  
Element Analysis ◽  
Mechanical Loads ◽  
Stiffness Anisotropy

Currently about 10 million Americans report signs and symptoms of TMJ dysfunction. One form of treatment for TMJ dysfunction is dental splints which reorient the jaw during mastication. This presumably changes the direction, magnitude and location of mechanical loads on the mandibular condyle of the temporomandibular joint (TMJ). The precise nature of load changes and their effect on the underlying condylar trabecular bone have not been reported.

Effects of Thresholding Techniques on μCT-Based Finite Element Models of Trabecular Bone

2006 ◽  
Vol 129 (4) ◽  
pp. 481-486 ◽  
Author(s):  
Chi Hyun Kim ◽  
Henry Zhang ◽  
George Mikhail ◽  
Dietrich von Stechow ◽  
Ralph Müller ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Trabecular Bone ◽  
Volume Fraction ◽  
Ct Images ◽  
Bone Volume ◽  
Finite Element Models ◽  
Micro Ct ◽  
Bone Volume Fraction ◽  
Element Analysis

Microimaging based finite element analysis is widely used to predict the mechanical properties of trabecular bone. The choice of thresholding technique, a necessary step in converting grayscale images to finite element models, can significantly influence the predicted bone volume fraction and mechanical properties. Therefore, we investigated the effects of thresholding techniques on microcomputed tomography (micro-CT) based finite element models of trabecular bone. Three types of thresholding techniques were applied to 16-bit micro-CT images of trabecular bone to create three different models per specimen. Bone volume fractions and apparent moduli were predicted and compared to experimental results. In addition, trabecular tissue mechanical parameters and morphological parameters were compared among different models. Our findings suggest that predictions of apparent mechanical properties and structural properties agree well with experimental measurements regardless of the choice of thresholding methods or the format of micro-CT images.

Finite Element Analysis of Tool Particle Interaction, Particle Volume Fraction, Size, Shape and Distribution in Machining of A356/SiCp

2018 ◽  
Vol 5 (8) ◽  
pp. 16800-16806 ◽  
Author(s):  
Y.J. Nithiya Sandhiya ◽  
M.M. Thamizharasan ◽  
B.V. Ajay Subramanyam ◽  
K.S. Vijay Sekar ◽  
S. Suresh Kumar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Particle Interaction ◽  
Particle Volume ◽  
Element Analysis ◽  
Fraction Size

scholarly journals The Quartic Piecewise-Linear Criterion for the Multiaxial Yield Behavior of Human Trabecular Bone

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Arnav Sanyal ◽  
Joanna Scheffelin ◽  
Tony M. Keaveny
Keyword(s):  
Finite Element ◽  
Trabecular Bone ◽  
Volume Fraction ◽  
Yield Criterion ◽  
Shear Loading ◽  
Bone Volume ◽  
Mechanical Anisotropy ◽  
Bone Volume Fraction ◽  
Human Trabecular Bone ◽  
Strain Space

Prior multiaxial strength studies on trabecular bone have either not addressed large variations in bone volume fraction and microarchitecture, or have not addressed the full range of multiaxial stress states. Addressing these limitations, we utilized micro-computed tomography (μCT) based nonlinear finite element analysis to investigate the complete 3D multiaxial failure behavior of ten specimens (5 mm cube) of human trabecular bone, taken from three anatomic sites and spanning a wide range of bone volume fraction (0.09–0.36), mechanical anisotropy (range of E3/E1 = 3.0–12.0), and microarchitecture. We found that most of the observed variation in multiaxial strength behavior could be accounted for by normalizing the multiaxial strength by specimen-specific values of uniaxial strength (tension, compression in the longitudinal and transverse directions). Scatter between specimens was reduced further when the normalized multiaxial strength was described in strain space. The resulting multiaxial failure envelope in this normalized-strain space had a rectangular boxlike shape for normal–normal loading and either a rhomboidal boxlike shape or a triangular shape for normal-shear loading, depending on the loading direction. The finite element data were well described by a single quartic yield criterion in the 6D normalized-strain space combined with a piecewise linear yield criterion in two planes for normal-shear loading (mean error ± SD: 4.6 ± 0.8% for the finite element data versus the criterion). This multiaxial yield criterion in normalized-strain space can be used to describe the complete 3D multiaxial failure behavior of human trabecular bone across a wide range of bone volume fraction, mechanical anisotropy, and microarchitecture.

scholarly journals Trabecular bone scales allometrically in mammals and birds

2011 ◽  
Vol 278 (1721) ◽  
pp. 3067-3073 ◽  
Author(s):  
Michael Doube ◽  
Michał M. Kłosowski ◽  
Alexis M. Wiktorowicz-Conroy ◽  
John R. Hutchinson ◽  
Sandra J. Shefelbine
Keyword(s):  
Finite Element ◽  
Trabecular Bone ◽  
Finite Element Modelling ◽  
Unit Volume ◽  
Volume Fraction ◽  
Bone Volume ◽  
Bone Volume Fraction ◽  
Element Modelling ◽  
Trabecular Network ◽  
Animal Size

Many bones are supported internally by a latticework of trabeculae. Scaling of whole bone length and diameter has been extensively investigated, but scaling of the trabecular network is not well characterized. We analysed trabecular geometry in the femora of 90 terrestrial mammalian and avian species with body masses ranging from 3 g to 3400 kg. We found that bone volume fraction does not scale substantially with animal size, while trabeculae in larger animals' femora are thicker, further apart and fewer per unit volume than in smaller animals. Finite element modelling indicates that trabecular scaling does not alter the bulk stiffness of trabecular bone, but does alter strain within trabeculae under equal applied loads. Allometry of bone's trabecular tissue may contribute to the skeleton's ability to withstand load, without incurring the physiological or mechanical costs of increasing bone mass.

Finite Element Analysis of <img src="/images/tex/20750.gif" alt="\hbox {Nb}_{3}\hbox {Sn}"> Sub-Cables Under Transverse Compression With Different Approaches

2013 ◽  
Vol 23 (3) ◽  
pp. 8400705-8400705 ◽  
Author(s):  
Tiening Wang ◽  
Luisa Chiesa ◽  
Makoto Takayasu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cross Sections ◽  
Load Distribution ◽  
Strain State ◽  
Transverse Load ◽  
Electrical Performance ◽  
Flat Plates ◽  
Element Analysis ◽  
Mechanical Loads

Currently, very few experimental results describing the behavior of Nb3Sn subcables under transverse load are available. Those results are of importance for predicting how a full-sized cable-in-conduit conductor behaves during operations. Current experimental devices used to study the effect of transverse load on the electrical performance of cables utilize concave plates to apply mechanical loads and contain the sample and subject it to mechanical loads that mimic the electromagnetic loads of full-sized cables during operation. From finite element analysis, it is found that the strain state in the strands of a triplet is greatly affected by the shape of the pressing element contact surface. We will discuss the strain state within the strands from the simulations using two pressing configurations: concave and flat plates. The strain state in each strand in a twisted triplet is investigated by considering two cross-sections of a triplet along the length of the cable. Those results can provide useful information on the electrical performance of each strand based on its location along the axis. It is verified that the load distribution is very different depending on the shape of the pressing plates.

Evaluation of 3D Embedded Element Technique in the Finite Element Analysis for the Composite

2019 ◽  
Vol 801 ◽  
pp. 65-70
Author(s):  
Jian Hong Gao ◽  
Xiao Xiang Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Aspect Ratio ◽  
Conventional Method ◽  
Volume Fraction ◽  
Fe Model ◽  
Element Analysis ◽  
High Fiber ◽  
Fiber Aspect Ratio ◽  
Element Technique

RVE combined with finite element analysis (FEA) is a very popular method to predict the mechanical property of the composite reinforced by short fibers. In the conventional method, generally the “tie” approach is used. By this method, the FE model with high fiber aspect ratio can not be achieved and the non-convergence of the numerical calculation may appear because of the complex mesh. The embedded element techinique is considered to be a replaceable method . Using this method, the mechanical behavior of composite with high fiber aspect ratio would be simulated. Therefore, in this study, the 3D solid element was employed for the FE model with multi cylinder particles. The comparisions of the Mise stress and the displacement between the embedded and conventional method indicate that compared with the stress transfer, the simulated result of composite stiffness is more accurate. In addition, the effects of model size, fiber orientated angle, fiber volume fraction and fiber aspect ratio were investigated. The numerical results were compared with the Mori-Tanaka model and the good agreements verify the applicability of the embedded element technique we studied in this paper.

Effect of Microcomputed Tomography Voxel Size on the Finite Element Model Accuracy for Human Cancellous Bone

2005 ◽  
Vol 127 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Yener N. Yeni ◽  
Gregory T. Christopherson ◽  
X. Neil Dong ◽  
Do-Gyoon Kim ◽  
David P. Fyhrie
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Boundary Conditions ◽  
Cancellous Bone ◽  
Coefficient Of Variation ◽  
Volume Fraction ◽  
Bone Volume ◽  
Bone Volume Fraction ◽  
Voxel Size ◽  
Fixed End

The level of structural detail that can be acquired and incorporated in a finite element (FE) analysis might greatly influence the results of microcomputed tomography (μCT)-based FE simulations, especially when relatively large bones, such as whole vertebrae, are of concern. We evaluated the effect of scanning and reconstruction voxel size on the μCT-based FE analyses of human cancellous tissue samples for fixed- and free-end boundary conditions using different combinations of scan/reconstruction voxel size. We found that the bone volume fraction (BV/TV) did not differ considerably between images scanned at 21 and 50 μm and reconstructed at 21, 50, or 110 μm (−0.5% to 7.8% change from the 21/21 μm case). For the images scanned and reconstructed at 110 μm, however, there was a large increase in BV/TV compared to the 21/21 μm case (58.7%). Fixed-end boundary conditions resulted in 1.8% [coefficient of variation (COV)] to 14.6% (E) difference from the free-end case. Dependence of model output parameters on scanning and reconstruction voxel size was similar between free- and fixed-end simulations. Up to 26%, 30%, 17.8%, and 32.3% difference in modulus (E), and average (VMExp), standard deviation (VMSD) and coefficient of variation (COV) of von Mises stresses, respectively, was observed between the 21/21 μm case and other scan/reconstruction combinations within the same (free or fixed) simulation group. Observed differences were largely attributable to scanning resolution, although reconstruction resolution also contributed significantly at the largest voxel sizes. All 21/21 μm results (taken as the gold standard) could be predicted from the 21/50 radj2=0.91-0.99;p<0.001, 21/110 radj2=0.58-0.99;p<0.02 and 50/50 results radj2=0.61-0.97;p<0.02. While BV/TV, VMSD, and VMExp/σz from the 21/21 could be predicted by those from the 50/110 radj2=0.63-0.93;p<0.02 and 110/110 radj2=0.41-0.77;p<0.05 simulations as well, prediction of E, VMExp, and COV became marginally significant 0.04<p<0.13 at 50/110 and nonsignificant at 110/110 0.21<p<0.70. In conclusion, calculation of cancellous bone modulus, mean trabecular stress, and other parameters are subject to large errors at 110/110 μm voxel size. However, enough microstructural details for studying bone volume fraction, trabecular shear stress scatter, and trabecular shear stress amplification VMExp/σz can be resolved using a 21/110 μm, 50/110 μm, and 110/110 μm voxels for both free- and fixed-end constraints.

Finite Element Analysis of X-Cor Sandwich’s Compressive Modulus

2011 ◽  
Vol 228-229 ◽  
pp. 259-264
Author(s):  
Xu Dan Dang ◽  
Meng Wei ◽  
Xin Li Wang ◽  
Jun Xiao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Analysis ◽  
Stress Field ◽  
Computational Model ◽  
Volume Fraction ◽  
Compressive Modulus ◽  
Finite Model ◽  
Element Analysis ◽  
Fraction Increase

By contrasting the two finite models, a practical finite element computational model of X-cor sandwich’s compressive modulus was proposed. Through numerical analysis the X-cor sandwich’s stress field and compressive modulus were achieved and the effects of changing Z-pin’s radius, density, angle and volume fraction to the X-cor sandwich’s compressive modulus were analyzed. The numerical analysis results indicate that as the Z-pin’s angle increases the X-cor sandwich’s compressive modulus decreases, as the Z-pin’s radius, density and volume fraction increase the X-cor sandwich’s compressive modulus increases. Through the computation of finite model the influencing trends of X-cor sandwich’s parameters are achieved and the rationality of the proposed finite model is verified.

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