scholarly journals Micro-finite-element method to assess elastic properties of trabecular bone at micro- and macroscopic level

Morphologie ◽  
2018 ◽  
Vol 102 (336) ◽  
pp. 12-20 ◽  
Author(s):  
R. Rieger ◽  
J.C. Auregan ◽  
T. Hoc
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Trabecular Bone ◽  
Elastic Properties ◽  
Macroscopic Level ◽  
Element Method

Fracture Mechanics of Architecture Dependent Fracture in Trabecular Bone Using the Cohesive Finite Element Method

2007 ◽  
Author(s):  
Vikas Tomar
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Trabecular Bone ◽  
Fracture Behavior ◽  
Bone Microstructure ◽  
Tissue Properties ◽  
Rate Dependent ◽  
Microdamage Accumulation ◽  
Element Method ◽  
Rate Of Loading

Trabecular bone fracture is closely related to the trabecular architecture and microdamage accumulation. Micro-finite element models have been used to investigate the elastic and yield properties of trabecular bone but have only seen limited application in modeling the microstructure dependent fracture of trabecular bone, [1, 2]. In the presented research a cohesive finite element method (CFEM) based approach that can be used to model microstructure and loading rate dependent fracture in trabecular bone is developed for the first time. The emphasis is on understanding the effect of the rate of loading and its correlation with the bone microstructure on the microdamage accumulation and fracture behavior in the trabecular bone. Analyses focus on understanding the effect of the rate of loading, change in bone tissue properties with aging, and their correlation with the bone microstructure on the microdamage accumulation and the fracture behavior in the trabecular bone.

A finite element method to investigate the elastic properties of pillared graphene sheet under different conditions

Carbon ◽  
2018 ◽  
Vol 140 ◽  
pp. 210-217 ◽  
Author(s):  
Lubin Song ◽  
Zhangxin Guo ◽  
Gin Boay Chai ◽  
Zhihua Wang ◽  
Yongcun Li ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Graphene Sheet ◽  
Elastic Properties ◽  
Element Method

Renewed Inflation of Krafla Caldera, Iceland, since 2018: Sensitivity of Ground Deformation to lateral variation in Earth structure and architecture of the magmatic system explored with the Finite Element Method

2020 ◽  
Author(s):  
Chiara Lanzi ◽  
Vincent Drouin ◽  
Siqi Li ◽  
Freysteinn Sigmundsson ◽  
Halldor Geirsson ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Properties ◽  
Ground Deformation ◽  
Vertical Displacement ◽  
Magma Source ◽  
The Finite Element Method ◽  
Spherical Source ◽  
Horizontal Displacements ◽  
Element Method

<p>The Krafla volcanic area in Northern Volcanic Zone of Iceland was characterized by deflation starting in 1989, suggesting a general pressure decrease and/or volume contraction at depth, which then exponentially decayed until having no significant deformation since around 2000.  In summer 2018, the volcano behaviour changed to inflation as observed both by Global Navigation Satellite System (GNSS) geodesy  and Sentinel-1 satellite radar interferometry (InSAR). Inflation since 2018 occurs at a rate of 10-14 mm/yr, centered in the middle of the caldera. No significant change in seismicity has occurred in the area in 2018, but seismic moment release ocurrs at a higher rate since middle 2019. Gravity stations in the area were remeasured in November 2019 for allowing comparison with earlier observations, and for providing reference for later studies. Initial modelling of the geodetic data is carried out assuming that the deformation is caused by a spherical source of pressure in an uniform elastic half-space. The result suggests that the deformation can be broadly explained by a single source of magma inflow at depth around 3.9-7.5 km, with the best-fit value around 4-4.5 km. We also apply the Finite Element Method (FEM) to additionally consider modification of the deformation field caused by Earth’s elastic heterogeneities and the uncertain geometry and  depth of the magma source. A set of FEM models are built with the COMSOL Multiphysics software in a 50x50 km domain where we test three different geometries of the source: a spherical source (radius 1000 km), a prolate ellipsoid,  and an oblate ellipsoid (sill-like) source, at 2.5, 4.0 and 5.5 km of depth. We also build a model to test how the vertical and horizontal displacements may be influenced by different elastic properties (e.g. Young’s modulus; about an order of magnitude different within a caldera boundary) for these sources. The results show that lateral variations in material properites can have a significant influence on ground deformation. Low-value Young’s inside caldera boundaries compared to higher values outside caldera boundaries will in particular influence the vertical displacement: the vertical displacement is about half of of what it is the original modelling.  The ratio of vertical to horizontal displacements will thus also be modified. This can in turn influence the inferred magma source geometry as it depends on the displacement ratios. The outcome of our study will provide better constrain for the elastic properties in Krafla area, and help understand the magma intrusion rate in the area.</p>

scholarly journals Effects of Moisture Content and Grain Direction on the Elastic Properties of Beech Wood Based on Experiment and Finite Element Method

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 610
Author(s):  
Wei-Lian Fu ◽  
Hui-Yuan Guan ◽  
Sawata Kei
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Moisture Content ◽  
Elastic Properties ◽  
Elastic Constants ◽  
Beech Wood ◽  
Wood Products ◽  
Moisture Contents ◽  
Wide Range ◽  
Element Method

Beech wood (Fagus sylvatica L.) is used in a wide range of wood products. However, the influence of the wood’s moisture content on its mechanical functions will affect its structural strength. It would be complicated and time-consuming to experimentally measure wood’s mechanical functions under different moisture contents. Therefore, it is necessary to establish a prediction formula between the moisture content and elastic constants, and then verify whether its mechanical functions within a wide range of moisture content can be studied by using FEM (finite element method). In this study, which was based on experimentation, we studied the influence of a wide range of moisture contents and grain direction on the compressive yield strength, modulus of elasticity and shear modulus of beech wood. The relationship between the moisture content and elastic constants was established; the moisture sensitivities of different elastic parameters were obtained. Ultimately, compression curves under different moisture contents were plotted out, using both FEM and experimentation. According to the results, the interaction of moisture with the grain direction had a significant effect on the elastic constants of wood, with grain direction having a greater effect on the elastic properties than the moisture content. Moreover, the decay function can be used to fit these experimental results well. The elastic constants of beech wood responded differently to the moisture content, depending on whether it was in the longitude or transverse directions. Finally, this study proved the feasibility of using FEM to simulate wood’s compressive performance with a wide range of moisture contents.

scholarly journals Computation of Effective Elastic Properties Using a Three-Dimensional Semi-Analytical Approach for Transversely Isotropic Nanocomposites

2021 ◽  
Vol 11 (4) ◽  
pp. 1867
Author(s):  
Monica Tapia ◽  
Y. Espinosa-Almeyda ◽  
R. Rodríguez-Ramos ◽  
José A. Otero
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Properties ◽  
Three Dimensional ◽  
Transversely Isotropic ◽  
Geometrical Shape ◽  
Effective Elastic Properties ◽  
Periodic Cell ◽  
Local Problems ◽  
Element Method

A three-dimensional semi-analytical finite element method (SAFEM-3D) is implemented in this work to calculate the effective properties of periodic elastic-reinforced nanocomposites. Different inclusions are also considered, such as discs, ellipsoidals, spheres, carbon nanotubes (CNT) and carbon nanowires (CNW). The nanocomposites are assumed to have isotropic or transversely isotropic inclusions embedded in an isotropic matrix. The SAFEM-3D approach is developed by combining the two-scale asymptotic homogenization method (AHM) and the finite element method (FEM). Statements regarding the homogenized local problems on the periodic cell and analytical expressions of the effective elastic coefficients are provided. Homogenized local problems are transformed into boundary problems over one-eighth of the cell. The FEM is implemented based on the principle of the minimum potential energy. The three-dimensional region (periodic cell) is divided into a finite number of 10-node tetrahedral elements. In addition, the effect of the inclusion’s geometrical shape, volume fraction and length on the effective elastic properties of the composite with aligned or random distributions is studied. Numerical computations are developed and comparisons with other theoretical results are reported. A comparison with experimental values for CNW nanocomposites is also provided, and good agreement is obtained.

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