Conferences and Presentations
















































p-FE analysis of the Proximal femur. International Workshop on High-Order Finite Element Methods, Herrsching, Germany May, 2007.


p-FE analysis of the human proximal femur compared to in-vitro experiments.

IACMM -20 Tel-Aviv University, Tel-Aviv, Israel May, 2006 


The behavior of safety glass under dynamic load.

The 30th Israeli conference of mechanical engineering, Tel-Aviv, Israel May, 2005


(1) Z. Yosibash, N. Trabelsi and C. Milgrom, 2007. Reliable simulations of the human proximal femur by high-order finite element analysis validated by experimental observations. Journal of Biomechanics 40, 3688–3699.


(2) Zohar Yosibash, Nir. Trabelsi and Christian Hellmich, 2008. Subject-specific p-FE analysis of the proximal femur utilizing micromechanics based material properties. International Journal for Multiscale Computational Engineering 6 (5), 483-498.


(3) Nir Trabelsi, Zohar Yosibash, and Charles Milgrom, 2009. Validation of subject-specific automated p-FE analysis of the proximal femur. Journal of Biomechanics 42, 234-241.

































תיבת טקסט: Mechanical response of the proximal femur: Finite element analyses validated by experimental observations.

The use of subject-specific FE models in clinical practice requires a high level of automation, validation and accurate evaluation of analysis prediction capabilities. This study present a novel high-order finite element method (p-FE) for generating FE models based on CT data. In the suggested method the geometry is represented by smooth surfaces accurately, based on QCT data. An internal smooth surface is used to separate the cortical and trabecular regions upon which a p-FE auto-mesh is constructed within each region (cortical or trabecular).

























תיבת טקסט: QCT Hounsfield Unit (HU) values are recalculated using a moving average method regardless of the FE mesh and isotropic inhomogeneous linear material representation was assigned to the FE models by a spatial function generated from the QCT data. Anisotropic material properties are also considered in the FE model and their influence will be presented. Calibration phantoms were used for the bone equivalent mineral density (EQM) calculation and Young's modulus were evaluated by Keyak & Falkinstein relations: 


To validate the FE results we performed QCT scans on three freshly frozen proximal femurs (30 years old male, 20 and 54 years old female) followed by mechanical in-vitro experiments at different inclination angles, measuring head deflection and strains at several points with a total of 77 experimental values recorded. The FE results, strains and displacements were compared to the in-vitro experiments. The linear regression of the experiment result vs. the FE prediction demonstrates the quality of the presented methods with a slope of 0.955 and R^2=0.957, results significantly better than in previous publications known to the authors.


































Ph.D. Research targets:


·        Enlarging the experimental data base for FE validation purposes.


·       Assigning anisotropic material properties to the FE model.


·       Investigate bones models affected by cancer tumors.


·       Optimization of implants position and dimensions in total hip head replacement.


·        Investigating tooth mechanical response by p-FE models generated from micro-CT data.




















Last Update: August 1, 2009