A Three-Dimensional Finite Element Scheme to Investigate the Apparent Mechanical Properties of Trabecular Bone

1999 ◽  
Vol 2 (4) ◽  
pp. 285-294 ◽  
Author(s):  
RAKESH SAXENA ◽  
TONY S. KELLERS ◽  
JOHN M. SULLIVAN
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Trabecular Bone ◽  
Three Dimensional ◽  
Finite Element Scheme ◽  
Element Scheme ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Finite Element Simulation of Ultrasound Propagation in Trabecular Bone

2013 ◽  
Author(s):  
Behzad Vafaeian ◽  
Yuchin Wu ◽  
Michael R. Doschak ◽  
Marwan El-Rich ◽  
Tarek El-Bialy ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Wave Propagation ◽  
Trabecular Bone ◽  
Quantitative Ultrasound ◽  
Three Dimensional ◽  
Osteoporotic Bone ◽  
Ultrasound Propagation ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Quantitative ultrasound is used to identify healthy versus osteoporotic bone. However the physics of ultrasound propagation in trabecular media is still not sufficiently understood. This lack of understanding is reported to be an obstacle in further development of this bone assessment technique. Numerical models of wave propagation stand as a potentially successful tool to explain the various experimental observations. The main issue in the numerical modeling of wave propagation in trabecular bone is the complex geometry of the trabecular structures surrounded by a fluid (bone marrow). So far, the complex geometrical domain of trabecular structures has been approximated by finite difference grids for wave propagation analyses. In this work, numerical simulation of ultrasound propagation into trabecular bone sample is performed using the finite element method (FEM). A new procedure for numerical modeling of trabecular bone tailored for the FEM is introduced. The entire complex trabecular geometries of two cubic bone samples are reconstructed using computed microtomography data. For the first time a three dimensional finite element mesh using tetrahedral elements is generated for the two-phase medium of a trabecular bone. Separate meshes for the bony part and the filling marrow (considered as non-viscous water) are generated and acoustic-structure interaction condition is imposed on their interface. It is shown that the three-dimensional simulation using the FEM can predict ultrasound propagation phenomena observed in experiments: linear dependency of attenuation on frequency, the effect of bone volume on the attenuation and speed of sound, and the propagation of fast and slow waves. Moreover, the broadband ultrasound attenuation (BUA) for two ultrasonic signals propagating into a healthy and an osteoporotic sample are compared. A distinguishable difference in BUA between the two samples is observed expressing lower BUA for osteoporotic bone. Our developed model is the first three-dimensional finite element analysis model to compare the ultrasound propagation in healthy versus osteoporotic bone. The developed model can be further utilized as a tool to explain various experimental observations of quantitative ultrasound of bone.

Three-dimensional finite element analysis of the effects of anisotropy on bone mechanical properties measured by nanoindentation

2004 ◽  
Vol 19 (1) ◽  
pp. 114-123 ◽  
Author(s):  
Z. Fan ◽  
J.Y. Rho ◽  
J.G. Swadener
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Cortical Bone ◽  
Three Dimensional ◽  
Indentation Modulus ◽  
Element Analysis ◽  
Fea Model ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A three-dimensional finite element analysis (FEA) model with elastic–plastic anisotropy was built to investigate the effects of anisotropy on nanoindentation measurements for cortical bone. The FEA model has demonstrated a capability to capture the cortical bone material response under the indentation process. By comparison with the contact area obtained from monitoring the contact profile in FEA simulations, the Oliver–Pharr method was found to underpredict or overpredict the contact area due to the effects of anisotropy. The amount of error (less than 10% for cortical bone) depended on the indentation orientation. The indentation modulus results obtained from FEA simulations at different surface orientations showed a trend similar to experimental results and were also similar to moduli calculated from a mathematical model. The Oliver–Pharr method has been shown to be useful for providing first-order approximations in the analysis of anisotropic mechanical properties of cortical bone, although the indentation modulus is influenced by anisotropy.

Influence of Platform and Abutment Angulation on Peri-Implant Bone. A Three-Dimensional Finite Element Stress Analysis

2013 ◽  
Vol 39 (6) ◽  
pp. 663-669 ◽  
Author(s):  
Ana Paula Martini ◽  
Rosália Moreira Barros ◽  
Amilcar Chagas Freitas Júnior ◽  
Eduardo Passos Rocha ◽  
Erika Oliveira de Almeida ◽  
...  
Keyword(s):  
Finite Element ◽  
Trabecular Bone ◽  
Three Dimensional ◽  
Central Incisor ◽  
Element Analysis ◽  
Anterior Maxilla ◽  
Dimensional Finite Element ◽  
Platform Switching ◽  
Solid Works ◽  
Three Dimensional Finite Element

The aim of this study was to evaluate stress distribution on the peri-implant bone, simulating the influence of Nobel Select implants with straight or angulated abutments on regular and switching platform in the anterior maxilla, by means of 3-dimensional finite element analysis. Four mathematical models of a central incisor supported by external hexagon implant (13 mm × 5 mm) were created varying the platform (R, regular or S, switching) and the abutments (S, straight or A, angulated 15°). The models were created by using Mimics 13 and Solid Works 2010 software programs. The numerical analysis was performed using ANSYS Workbench 10.0. Oblique forces (100 N) were applied to the palatine surface of the central incisor. The bone/implant interface was considered perfectly integrated. Maximum (σmax) and minimum (σmin) principal stress values were obtained. For the cortical bone the highest stress values (σmax) were observed in the RA (regular platform and angulated abutment, 51 MPa), followed by SA (platform switching and angulated abutment, 44.8 MPa), RS (regular platform and straight abutment, 38.6 MPa) and SS (platform switching and straight abutment, 36.5 MPa). For the trabecular bone, the highest stress values (σmax) were observed in the RA (6.55 MPa), followed by RS (5.88 MPa), SA (5.60 MPa), and SS (4.82 MPa). The regular platform generated higher stress in the cervical periimplant region on the cortical and trabecular bone than the platform switching, irrespective of the abutment used (straight or angulated).

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