Study of Pullout Performance of Self-Tapping Screws for Human Bone

2011 ◽  
Author(s):  
Zhijun Wu ◽  
Sayed A. Nassar ◽  
Xianjie Yang
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Analytical Model ◽  
Material Properties ◽  
Pedicle Screws ◽  
Pullout Strength ◽  
Bone Material ◽  
Synthetic Bone ◽  
Failure Propagation ◽  
Device Applications

The study investigates the pullout strength of self-tapping pedicle screws using analytical, finite element, and experimental methodologies with focus on medical device applications. The stress distribution and failure propagation around implant threads in the synthetic bone during the pullout process, as well as the pullout strength of pedicle screws, are explored. Based on the FEA results, an analytical model for the pullout strength of the pedicle screw is constructed in terms of the synthetic bone material properties, screw size, and implant depth. The characteristics of pullout behavior of self-tapping pedicle screws are discussed. Both the analytical model and finite element results are validated using experimental techniques.

Pullout Performance of Self-Tapping Medical Screws

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
Zhijun Wu ◽  
Sayed A. Nassar ◽  
Xianjie Yang
Keyword(s):  
Finite Element ◽  
The Self ◽  
Propagation Mode ◽  
Finite Element Models ◽  
Pullout Strength ◽  
Element Analysis ◽  
Synthetic Bone ◽  
Pilot Hole ◽  
The Finite Element Analysis ◽  
Failure Propagation

This study investigates the effect of the pilot hole size, implant depth, synthetic bone density, and screw size on the pullout strength of the self-tapping screw using analytical, finite element, and experimental methodologies. Stress distribution and failure propagation mode around the implant thread zone are also investigated. Based on the finite element analysis (FEA) results, an analytical model for the pullout strength of the self-tapping screw is constructed in terms of the (synthetic) bone mechanical properties, screw size, and the implant depth. The pullout performance of self-tapping screws is discussed. Results from the analytical and finite element models are experimentally validated.

scholarly journals Increase of pullout strength of spinal pedicle screws with conical core: Biomechanical tests and finite element analyses

2005 ◽  
Vol 23 (4) ◽  
pp. 788-794 ◽  
Author(s):  
Ching-Chi Hsu ◽  
Ching-Kong Chao ◽  
Jaw-Lin Wang ◽  
Sheng-Mou Hou ◽  
Ying-Tsung Tsai ◽  
...  
Keyword(s):  
Finite Element ◽  
Pedicle Screws ◽  
Finite Element Analyses ◽  
Pullout Strength ◽  
Biomechanical Tests

scholarly journals Material property and boundary condition effects on stresses in avalanche snow-packs

1974 ◽  
Vol 13 (67) ◽  
pp. 99-108 ◽  
Author(s):  
J. O. Curtis ◽  
F. W. Smith
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Stress Distribution ◽  
Computer Program ◽  
Material Properties ◽  
Shear Failure ◽  
Stress Distributions ◽  
Snow Pack ◽  
Snow Layer ◽  
Linear Elastic

A linear elastic finite element computer program was applied to determine the stress distributions in multi-layered snow-packs typical of those found at Berthoud Pass, Colorado. The effect on stress distribution of wide variations in elastic material properties was examined. Also, an attempt was made to model the shear failure of a weak sub-layer in the snow-pack by relaxing the condition that the bottom snow layer be firmly attached to the ground.

Finite Element Analysis of Human Tibia Modeled as a Functionally Graded Material

2019 ◽  
Vol 2 (3) ◽  
Author(s):  
Ashish Tiwari ◽  
Pankaj Wahi ◽  
Niraj Sinha
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Functionally Graded Material ◽  
Material Properties ◽  
Functionally Graded ◽  
Element Analysis ◽  
Cross Sectional ◽  
Human Tibia ◽  
Graded Material

Human tibia, the second largest bone in human body, is made of complex biological material having inhomogeneity and anisotropy in such a manner that makes it a functionally graded material. While analyses of human tibia assuming it to be made of different material regions have been attempted in past, functionally graded nature of the bone in the mechanical analysis has not been considered. This study highlights the importance of functional grading of material properties in capturing the correct stress distribution from the finite element analysis (FEA) of human tibia under static loading. Isotropic and orthotropic material properties of different regions of human tibia have been graded functionally in three different manners and assigned to the tibia model. The nonfunctionally graded and functionally graded models of tibia have been compared with each other. It was observed that the model in which functional grading was not performed, uneven distribution and unrealistic spikes of stresses occurred at the interfaces of different material regions. On the contrary, the models with functional grading were free from this potential artifact. Hence, our analysis suggests that functional grading is essential for predicting the actual distribution of stresses in the entire bone, which is important for biomechanical analysis. We find that orthotropic nature of the bone tends to increase the maximum von Mises stress in the entire tibia, while inclusion of cross-sectional inhomogeneity typically increases the stresses across normal cross section. Accordingly, our analysis suggests that both orthotropy as well as cross-sectional inhomogeneity should be included to correctly capture the stress distribution in the bone.

Impact of Grain Structure and Material Properties on Via Extrusion in 3D Interconnects

2015 ◽  
Vol 12 (3) ◽  
pp. 118-122 ◽  
Author(s):  
Tengfei Jiang ◽  
Chenglin Wu ◽  
Jay Im ◽  
Rui Huang ◽  
Paul S. Ho
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Grain Size ◽  
Finite Element ◽  
Analytical Model ◽  
Material Properties ◽  
Grain Structure ◽  
Element Analysis ◽  
Silicon Vias ◽  
The Relationship

In this article, the effects of Cu microstructure on the mechanical properties and extrusion of through-silicon vias (TSVs) were studied based on two types of TSVs with different microstructure. A direct correlation was found between the grain size and the mechanical properties of the vias. Both an analytical model and finite element analysis (FEA) were used to establish the relationship between the mechanical properties and via extrusion. The effect of via/Si interface on extrusion was also studied by FEA. The results suggest small and uniform grains in the Cu vias, as well as stronger interfaces between the via and Si led to smaller via extrusion, and are thus preferable for reduced via extrusion failure and improved TSV reliability.

A new approach for assigning bone material properties from CT images into finite element models

2010 ◽  
Vol 43 (5) ◽  
pp. 1011-1015 ◽  
Author(s):  
G. Chen ◽  
B. Schmutz ◽  
D. Epari ◽  
K. Rathnayaka ◽  
S. Ibrahim ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Ct Images ◽  
Finite Element Models ◽  
Bone Material ◽  
New Approach ◽  
Bone Material Properties

scholarly journals Material property and boundary condition effects on stresses in avalanche snow-packs

1974 ◽  
Vol 13 (67) ◽  
pp. 99-108 ◽  
Author(s):  
J. O. Curtis ◽  
F. W. Smith
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Stress Distribution ◽  
Computer Program ◽  
Material Properties ◽  
Shear Failure ◽  
Stress Distributions ◽  
Snow Pack ◽  
Snow Layer ◽  
Linear Elastic

A linear elastic finite element computer program was applied to determine the stress distributions in multi-layered snow-packs typical of those found at Berthoud Pass, Colorado. The effect on stress distribution of wide variations in elastic material properties was examined. Also, an attempt was made to model the shear failure of a weak sub-layer in the snow-pack by relaxing the condition that the bottom snow layer be firmly attached to the ground.

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