Microstructure-Based Modeling of Ti-6Al-4V Lattice Structures and Trabecular Bone

2010 ◽  
Author(s):  
Hang Yao ◽  
Wei Tong
Keyword(s):  
Trabecular Bone ◽  
Mechanical Test ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Bone Diseases ◽  
Bone Architecture ◽  
Fe Model ◽  
Micro Computed Tomography ◽  
Nondestructive Investigation ◽  
The Relationship

Knowledge of mechanical properties of bones is important for the designing of bone replacements and implants as well as the research of bone diseases such as osteoporosis. However, bone, especially trabecular bone, is a highly anisotropic and heterogeneous living tissue. Micro-computed-tomography (micro-CT) and three-dimensional ultrasound imaging techniques are valuable tools for nondestructive investigation of three-dimensional trabecular bone architecture. From a reconstruction of trabecular bone, a numerical model such as finite element (FE) model can be generated. Using this FE model to simulate compression test, and comparing the simulation results to the results from real mechanical test of the same specimen, the relationship between the observed mechanical behaviors and the microstructure can be established.

The Effect of Trabecular Bone on the Mechanical Response of Human Mandible with Implant

2014 ◽  
Vol 695 ◽  
pp. 588-591
Author(s):  
Khairul Salleh Basaruddin ◽  
Ruslizam Daud
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Trabecular Bone ◽  
Static Analysis ◽  
Load Distribution ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Fe Model ◽  
Micro Computed Tomography ◽  
Bone Specimen

This study aims to investigate the influence of trabecular bone in human mandible bone on the mechanical response under implant load. Three dimensional voxel finite element (FE) model of mandible bone was reconstructed from micro-computed tomography (CT) images that were captured from bone specimen. Two FE models were developed where the first consists of cortical bone, trabecular bone and implants, and trabecular bone part was excluded in the second model. A static analysis was conducted on both models using commercial software Voxelcon. The results suggest that trabecular bone contributed to the strength of human mandible bone and to the effectiveness of load distribution under implant load.

EFFECT OF STRESS INTENSITY FACTOR IN EVALUATION OF INSTABILITY OF ATHEROSCLEROTIC PLAQUE

2014 ◽  
Vol 14 (05) ◽  
pp. 1450072 ◽  
Author(s):  
HADI MOHAMMADI ◽  
KIBRET MEQUANINT
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Future Research ◽  
Plaque Morphology ◽  
Fe Model ◽  
Fibrous Cap ◽  
Arterial Blood ◽  
Proposed Model ◽  
Fibrous Cap Thickness ◽  
The Relationship

Understanding the relationship between coronary arterial blood pressure, plaque morphology and composition, and sites of fibrous cap (FC) bursting, has been the focus of many recent studies. Instability of atherosclerotic plaques, defined as the propensity for FCs to burst, has been thought to occur at places where FCs are thin and necrotic core (NC) areas are large and highly compliant. However, here we show quantitatively, using a fiber-reinforced, anisotropic and hyperelastic FE model, that FC thickness and NC size and compliance alone are limited in predicting vulnerable and high-risk plaques. We suggest that plaque instabilities primarily occur at sites of high and concentrated mechanical stresses irrespective of fibrous cap thickness or NC area and compliance. Also, limitations of imaging techniques, such as intravascular ultrasound and optical coherence tomography, for providing input into (FE) models of atherosclerosis are discussed. The proposed model can be used to predict vulnerable plaque sites and rupture risks in patients. The current study also provides a framework for future research in which three-dimensional platform and viscoelastic properties of plaque composition can be considered in time-dependent and fatigue studies.

scholarly journals Masticatory biomechanics in the rabbit: a multi-body dynamics analysis

2014 ◽  
Vol 11 (99) ◽  
pp. 20140564 ◽  
Author(s):  
Peter J. Watson ◽  
Flora Gröning ◽  
Neil Curtis ◽  
Laura C. Fitton ◽  
Anthony Herrel ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Muscle Fibres ◽  
Micro Computed Tomography ◽  
Body Dynamics ◽  
Masticatory System ◽  
Muscle Groups ◽  
Muscle Activations ◽  
Multi Body

Multi-body dynamics is a powerful engineering tool which is becoming increasingly popular for the simulation and analysis of skull biomechanics. This paper presents the first application of multi-body dynamics to analyse the biomechanics of the rabbit skull. A model has been constructed through the combination of manual dissection and three-dimensional imaging techniques (magnetic resonance imaging and micro-computed tomography). Individual muscles are represented with multiple layers, thus more accurately modelling muscle fibres with complex lines of action. Model validity was sought through comparing experimentally measured maximum incisor bite forces with those predicted by the model. Simulations of molar biting highlighted the ability of the masticatory system to alter recruitment of two muscle groups, in order to generate shearing or crushing movements. Molar shearing is capable of processing a food bolus in all three orthogonal directions, whereas molar crushing and incisor biting are predominately directed vertically. Simulations also show that the masticatory system is adapted to process foods through several cycles with low muscle activations, presumably in order to prevent rapidly fatiguing fast fibres during repeated chewing cycles. Our study demonstrates the usefulness of a validated multi-body dynamics model for investigating feeding biomechanics in the rabbit, and shows the potential for complementing and eventually reducing in vivo experiments.

scholarly journals Deciphering an extreme morphology: bone microarchitecture of the hero shrew backbone (Soricidae: Scutisorex )

2020 ◽  
Vol 287 (1926) ◽  
pp. 20200457 ◽  
Author(s):  
Stephanie M. Smith ◽  
Kenneth D. Angielczyk
Keyword(s):  
Trabecular Bone ◽  
Sagittal Plane ◽  
Bone Microarchitecture ◽  
Compressive Load ◽  
Bone Architecture ◽  
Micro Computed Tomography ◽  
Vertebral Centra ◽  
Behavioural Patterns ◽  
Compressive Loads

Biological structures with extreme morphologies are puzzling because they often lack obvious functions and stymie comparisons to homologous or analogous features with more typical shapes. An example of such an extreme morphotype is the uniquely modified vertebral column of the hero shrew Scutisorex , which features numerous accessory intervertebral articulations and massively expanded transverse processes. The function of these vertebral structures is unknown, and it is difficult to meaningfully compare them to vertebrae from animals with known behavioural patterns and spinal adaptations. Here, we use trabecular bone architecture of vertebral centra and quantitative external vertebral morphology to elucidate the forces that may act on the spine of Scutisorex and that of another large shrew with unmodified vertebrae ( Crocidura goliath ). X-ray micro-computed tomography (µCT) scans of thoracolumbar columns show that Scutisorex thori is structurally intermediate between C. goliath and S. somereni internally and externally, and both Scutisorex species exhibit trabecular bone characteristics indicative of higher in vivo axial compressive loads than C. goliath. Under compressive load, Scutisorex vertebral morphology is adapted to largely restrict bending to the sagittal plane (flexion). Although these findings do not solve the mystery of how Scutisorex uses its byzantine spine in vivo , our work suggests potentially fruitful new avenues of investigation for learning more about the function of this perplexing structure.

Three-Dimensional Local Measurements of Bone Strain and Displacement: Comparison of Three Digital Volume Correlation Approaches

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Marco Palanca ◽  
Gianluca Tozzi ◽  
Luca Cristofolini ◽  
Marco Viceconti ◽  
Enrico Dall'Ara
Keyword(s):  
Trabecular Bone ◽  
Cortical Bone ◽  
Computational Cost ◽  
Three Dimensional ◽  
Digital Volume Correlation ◽  
Micro Computed Tomography ◽  
Local Approach ◽  
Accuracy And Precision ◽  
Local Measurements ◽  
The Difference

Different digital volume correlation (DVC) approaches are currently available or under development for bone tissue micromechanics. The aim of this study was to compare accuracy and precision errors of three DVC approaches for a particular three-dimensional (3D) zero-strain condition. Trabecular and cortical bone specimens were repeatedly scanned with a micro-computed tomography (CT). The errors affecting computed displacements and strains were extracted for a known virtual translation, as well as for repeated scans. Three DVC strategies were tested: two local approaches, based on fast-Fourier-transform (DaVis-FFT) or direct-correlation (DaVis-DC), and a global approach based on elastic registration and a finite element (FE) solver (ShIRT-FE). Different computation subvolume sizes were tested. Much larger errors were found for the repeated scans than for the virtual translation test. For each algorithm, errors decreased asymptotically for larger subvolume sizes in the range explored. Considering this particular set of images, ShIRT-FE showed an overall better accuracy and precision (a few hundreds microstrain for a subvolume of 50 voxels). When the largest subvolume (50–52 voxels) was applied to cortical bone, the accuracy error obtained for repeated scans with ShIRT-FE was approximately half of that for the best local approach (DaVis-DC). The difference was lower (250 microstrain) in the case of trabecular bone. In terms of precision, the errors shown by DaVis-DC were closer to the ones computed by ShIRT-FE (differences of 131 microstrain and 157 microstrain for cortical and trabecular bone, respectively). The multipass computation available for DaVis software improved the accuracy and precision only for the DaVis-FFT in the virtual translation, particularly for trabecular bone. The better accuracy and precision of ShIRT-FE, followed by DaVis-DC, were obtained with a higher computational cost when compared to DaVis-FFT. The results underline the importance of performing a quantitative comparison of DVC methods on the same set of samples by using also repeated scans, other than virtual translation tests only. ShIRT-FE provides the most accurate and precise results for this set of images. However, both DaVis approaches show reasonable results for large nodal spacing, particularly for trabecular bone. Finally, this study highlights the importance of using sufficiently large subvolumes, in order to achieve better accuracy and precision.

3D Micro-Tomographic imaging and Quantitative Morphometry for the Nondestructive Evaluation of Porous Biomaterials

1996 ◽  
Vol 461 ◽  
Author(s):  
R. Müller ◽  
S. Matter ◽  
P. Neuenschwander ◽  
U. W. Suter ◽  
P. Rüegsegger
Keyword(s):  
Three Dimensional ◽  
Staining Technique ◽  
Bone Architecture ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Degree Of Anisotropy ◽  
Low X ◽  
Porous Biomaterials ◽  
Structural Indices ◽  
X Ray Absorption

ABSTRACTMicro-computed tomography (μCT) is a new and emerging technique for the nondestructive assessment and analysis of the three-dimensional trabecular bone architecture. The applications of μCT with respect to the analysis of bone are manyfold. Nevertheless, it also holds high promise for the microstructural measurement and analysis of porous biomaterials. For the purpose of the study, a desk-top μCT providing a nominal isotropie resolution of 14 μm was used. Since the polymeric material has a very low X-ray absorption coefficient, the scaffolds were stained prior to measurement using a commercial X-ray contrast agent. This allowed not only to acquire important microstructural features of the diree-dimensional scaffold but also to compute standard structural indices such as BV/TV, BS/BV, Tb.N, Tb.Th, Tb.Sp and the degree of anisotropy (DA) using mean intercept length measurements. The preliminary results show that different types of scaffolds can be distinguished both qualitatively (visualization) and quantitatively (morphometry) provided an adequate X-ray staining technique is used. It can be concluded that, in the future, μCT may be of considerable help in basic as well as in applied research and development.

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