Long Bone Torsion: I. Effects of Heterogeneity, Anisotropy and Geometric Irregularity

1985 ◽  
Vol 107 (2) ◽  
pp. 183-188 ◽  
Author(s):  
J. G. Kennedy ◽  
D. R. Carter
Keyword(s):  
Finite Element ◽  
Bone Geometry ◽  
Long Bone ◽  
Finite Element Models ◽  
Long Bones ◽  
Cross Sectional ◽  
Torsional Response ◽  
Simple Models

The influences of heterogeneity, anisotropy and geometric irregularity on the unrestrained, linearly elastic torsional response of long bones are assessed. Longitudinal geometric variations contribute insignificantly to the torsional response for typical long bone geometries. Anisotropy, heterogeneity and transverse geometric irregularity significantly influence the torsional response. A procedure is discussed which uses an approximate means to characterize both heterogeneity and anisotropy in predicting the torsional response. The accuracy of circular and elliptical annulus models of the bone cross-sectional geometry are assessed by comparing the stress predictions of these simple models to those of finite element models of the bone geometry.

Subject-specific finite element models can accurately predict strain levels in long bones

2007 ◽  
Vol 40 (13) ◽  
pp. 2982-2989 ◽  
Author(s):  
Enrico Schileo ◽  
Fulvia Taddei ◽  
Andrea Malandrino ◽  
Luca Cristofolini ◽  
Marco Viceconti
Keyword(s):  
Finite Element ◽  
Finite Element Models ◽  
Long Bones ◽  
Subject Specific

Subject-specific finite element models of long bones: An in vitro evaluation of the overall accuracy

2006 ◽  
Vol 39 (13) ◽  
pp. 2457-2467 ◽  
Author(s):  
Fulvia Taddei ◽  
Luca Cristofolini ◽  
Saulo Martelli ◽  
H.S. Gill ◽  
Marco Viceconti
Keyword(s):  
Finite Element ◽  
Finite Element Models ◽  
Long Bones ◽  
In Vitro Evaluation ◽  
Subject Specific

Modelling of Rotating Twisted Blades as 1D Continuum

2016 ◽  
Vol 821 ◽  
pp. 183-190
Author(s):  
Jan Brůha ◽  
Drahomír Rychecký
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Beam Theory ◽  
Parameter Tuning ◽  
Finite Element Models ◽  
Cross Sectional ◽  
One Dimensional ◽  
Rayleigh Beam ◽  
Twisted Blade ◽  
Sectional Parameters

Presented paper deals with modelling of a twisted blade with rhombic shroud as one-dimensional continuum by means of Rayleigh beam finite elements with varying cross-sectional parameters along the finite elements. The blade is clamped into a rotating rigid disk and the shroud is considered to be a rigid body. Since the finite element models based on the Rayleigh beam theory tend to slightly overestimate natural frequencies and underestimate deflections in comparison with finite element models including shear deformation effects, parameter tuning of the blade is performed.

scholarly journals Electrical Capacitance Tomography (ECT) Electrode Size Simulation Study for Cultured Cell

2021 ◽  
Vol 2071 (1) ◽  
pp. 012052
Author(s):  
N A Zulkiflli ◽  
M D Shahrulnizahani ◽  
X F Hor ◽  
F A Phang ◽  
M F Rahmat ◽  
...  
Keyword(s):  
Finite Element ◽  
Cultured Cells ◽  
Electrical Capacitance Tomography ◽  
Finite Element Models ◽  
Capacitive Sensing ◽  
Electrical Capacitance ◽  
Cross Sectional ◽  
Electrode Size ◽  
Cell Monitoring ◽  
Capacitance Tomography

Abstract Cell sensing and monitoring using capacitive sensors are widely used in cell monitoring because of the flexible and uncomplicated design and fabrication. Previous work from many different fields of applications has integrated capacitive sensing technique with tomography to produce cross-sectional images of the internal dielectric distribution. This paper carried an investigation on the capabilities of four 16-channel sensor electrodes with different electrode sizes to detect the change in the dielectric distribution of the cultured cells. All three 16-channel sensor electrodes are designed and simulate on COMSOL 6.3a Multiphysics. The pre-processing results obtained from three finite element models (FEM) of ECT sensor configurations in detecting the cell phantom shows that bigger electrodes size are more sensitive to permittivity distribution.

scholarly journals Morphometric Maps of Bilateral Asymmetry in the Human Humerus: An Implementation in the R Package Morphomap

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1711
Author(s):  
Antonio Profico ◽  
Carlotta Zeppilli ◽  
Ileana Micarelli ◽  
Alessandro Mondanaro ◽  
Pasquale Raia ◽  
...  
Keyword(s):  
R Package ◽  
Long Bone ◽  
Biological Anthropology ◽  
Long Bones ◽  
Loading History ◽  
Biological Profile ◽  
Cross Sectional ◽  
Novel Approach ◽  
Males And Females ◽  
Major Factors

In biological anthropology, parameters relating to cross-sectional geometry are calculated in paired long bones to evaluate the degree of lateralization of anatomy and, by inference, function. Here, we describe a novel approach, newly added to the morphomap R package, to assess the lateralization of the distribution of cortical bone along the entire diaphysis. The sample comprises paired long bones belonging to 51 individuals (10 females and 41 males) from The New Mexico Decedent Image Database with known biological profile, occupational and loading histories. Both males and females show a pattern of right lateralization. In addition, males are more lateralized than females, whereas there is not a significant association between lateralization with occupation and loading history. Body weight, height and long-bone length are the major factors driving the emergence of asymmetry in the humerus, while interestingly, the degree of lateralization decreases in the oldest individuals.

scholarly journals High throughput phenotyping of cross-sectional morphology to assess stalk lodging resistance

Plant Methods ◽  
2022 ◽  
Vol 18 (1) ◽  
Author(s):  
Yusuf A. Oduntan ◽  
Christopher J. Stubbs ◽  
Daniel J. Robertson
Keyword(s):  
Finite Element ◽  
High Throughput ◽  
Plant Traits ◽  
Finite Element Models ◽  
Vascular Bundles ◽  
Lodging Resistance ◽  
Cross Sectional ◽  
Conium Maculatum ◽  
Finite Element Software ◽  
Stalk Lodging

Abstract Background Stalk lodging (mechanical failure of plant stems during windstorms) leads to global yield losses in cereal crops estimated to range from 5% to 25% annually. The cross-sectional morphology of plant stalks is a key determinant of stalk lodging resistance. However, previously developed techniques for quantifying cross-sectional morphology of plant stalks are relatively low-throughput, expensive and often require specialized equipment and expertise. There is need for a simple and cost-effective technique to quantify plant traits related to stalk lodging resistance in a high-throughput manner. Results A new phenotyping methodology was developed and applied to a range of plant samples including, maize (Zea mays), sorghum (Sorghum bicolor), wheat (Triticum aestivum), poison hemlock (Conium maculatum), and Arabidopsis (Arabis thaliana). The major diameter, minor diameter, rind thickness and number of vascular bundles were quantified for each of these plant types. Linear correlation analyses demonstrated strong agreement between the newly developed method and more time-consuming manual techniques (R2 > 0.9). In addition, the new method was used to generate several specimen-specific finite element models of plant stalks. All the models compiled without issue and were successfully imported into finite element software for analysis. All the models demonstrated reasonable and stable solutions when subjected to realistic applied loads. Conclusions A rapid, low-cost, and user-friendly phenotyping methodology was developed to quantify two-dimensional plant cross-sections. The methodology offers reduced sample preparation time and cost as compared to previously developed techniques. The new methodology employs a stereoscope and a semi-automated image processing algorithm. The algorithm can be used to produce specimen-specific, dimensionally accurate computational models (including finite element models) of plant stalks.

An Experimental Investigation of Deformation of Plated Holes for a Single 30-210-30°C Thermal Cycle

1994 ◽  
Vol 116 (1) ◽  
pp. 1-5 ◽  
Author(s):  
T. S. Gross ◽  
J. A. Perault ◽  
D. W. Watt
Keyword(s):  
Finite Element ◽  
Thermal Cycle ◽  
Compressive Strain ◽  
Large Diameter ◽  
Temperature Cycle ◽  
Finite Element Models ◽  
Elastic Analysis ◽  
Printed Wiring Board ◽  
Cross Sectional ◽  
Full Temperature

The out-of-plane displacement field around two plated holes with different pad diameters in an FR-4 printed wiring board was measured for a single 30°C–210°C–30°C temperature cycle using electro-optic holographic interferometry. At the end of the temperature cycle, the outside edge of the pad was raised above the level of the laminate and the inside edge was depressed below the level of the laminate. This indicates that the barrel is plastically deformed in compression to a total strain of approximately 0.58–0.66 percent which is well above typical yield strains of 0.2 percent. The smaller diameter pad was inclined more than the large diameter pad, but the residual compressive strain in the barrel was roughly the same. Both the residual compressive strain and the inward inclination of the pad are in conflict with the predictions of most finite element models of plated hole deformation. However, there were cracks at the pad-barrel interface which are not included in finite element models. The residual compressive deformation of the barrel is attributed to inelastic deformation of the FR-4 matrix at the high end of the thermal cycle. The stress in the barrel was estimated using an approximate elastic analysis of pad deflections. The estimated stress for different hole diameters for the same pad diameter was roughly proportional to the ratio of their barrel plating cross-sectional areas for a 30–150°C temperature change. The elastic analysis is shown to predict (unrealistic) tensile barrel stresses at the end of the full temperature cycle.

scholarly journals Finite Element Study on Continuous Rotating versus Reciprocating Nickel-Titanium Instruments

2016 ◽  
Vol 27 (4) ◽  
pp. 436-441 ◽  
Author(s):  
Mohamed I. El-Anwar ◽  
Salah A. Yousief ◽  
Engy M. Kataia ◽  
Tarek M. Abd El-Wahab
Keyword(s):  
Finite Element ◽  
Low Cost ◽  
Nickel Titanium ◽  
Finite Element Models ◽  
Element Analysis ◽  
Cross Sectional ◽  
Design And Manufacturing ◽  
Cad Cam ◽  
Strain Stress ◽  
Sectional Shape

Abstract In the present study, GTX and ProTaper as continuous rotating endodontic files were numerically compared with WaveOne reciprocating file using finite element analysis, aiming at having a low cost, accurate/trustworthy comparison as well as finding out the effect of instrument design and manufacturing material on its lifespan. Two 3D finite element models were especially prepared for this comparison. Commercial engineering CAD/CAM package was used to model full detailed flute geometries of the instruments. Multi-linear materials were defined in analysis by using real strain-stress data of NiTi and M-Wire. Non-linear static analysis was performed to simulate the instrument inside root canal at a 45° angle in the apical portion and subjected to 0.3 N.cm torsion. The three simulations in this study showed that M-Wire is slightly more resistant to failure than conventional NiTi. On the other hand, both materials are fairly similar in case of severe locking conditions. For the same instrument geometry, M-Wire instruments may have longer lifespan than the conventional NiTi ones. In case of severe locking conditions both materials will fail similarly. Larger cross sectional area (function of instrument taper) resisted better to failure than the smaller ones, while the cross sectional shape and its cutting angles could affect instrument cutting efficiency.

A Method to Improve Experimental Validation of Finite-Element Models of Long Bones

Strain ◽  
2008 ◽  
Vol 46 (3) ◽  
pp. 242-251 ◽  
Author(s):  
M. Juszczyk ◽  
E. Schileo ◽  
S. Martelli ◽  
L. Cristofolini ◽  
M. Viceconti
Keyword(s):  
Finite Element ◽  
Experimental Validation ◽  
Finite Element Models ◽  
Long Bones

scholarly journals High Throughput Phenotyping of Cross-sectional Morphology to Assess Stalk Lodging Resistance

2021 ◽  
Author(s):  
Yusuf A Oduntan ◽  
Christopher J Stubbs ◽  
Daniel J Robertson
Keyword(s):  
Finite Element ◽  
High Throughput ◽  
Plant Traits ◽  
Finite Element Models ◽  
Vascular Bundles ◽  
Lodging Resistance ◽  
Cross Sectional ◽  
Conium Maculatum ◽  
Finite Element Software ◽  
Stalk Lodging

Abstract Background Stalk lodging (mechanical failure of plant stems during windstorms) leads to global yield losses in cereal crops estimated to range from 5% - 25% annually. The cross-sectional morphology of plant stalks is a key determinant of stalk lodging resistance. However, previously developed techniques for quantifying cross-sectional morphology of plant stalks are relatively low-throughput, expensive and often require specialized equipment and expertise. There is need for a simple and cost-effective technique to quantify plant traits related to stalk lodging resistance in a high-throughput manner.Results A new phenotyping methodology was developed and applied to a range of plant samples including, maize (Zea mays), sorghum (Sorghum bicolor), wheat (Triticum aestivum), poison hemlock (Conium maculatum), and Arabidopsis (Arabis thaliana). The major diameter, minor diameter, rind thickness and number of vascular bundles were quantified for each of these plant types. Linear correlation analyses demonstrated strong agreement between the newly developed method and more time-consuming manual techniques (R2>0.9). In addition, the new method was used to generate several specimen-specific finite element models of plant stalks. All the models compiled without issue and were successfully imported into finite element software for analysis. All the models demonstrated reasonable and stable solutions when subjected to realistic applied loads.Conclusions A rapid, low-cost, and user-friendly phenotyping methodology was developed to quantify two-dimensional plant cross-sections. The methodology offers reduced sample preparation time and cost as compared to previously developed techniques. The new methodology employs a stereoscope and a semi-automated image processing algorithm. The algorithm can be used to produce specimen-specific, dimensionally accurate computational models (including finite element models) of plant stalks.

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