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.

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.

The Crash-Box Crashworthiness Design Based on RCAR Tests

2014 ◽  
Vol 971-973 ◽  
pp. 781-784
Author(s):  
Hong Lan Liu ◽  
Ning Hu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Models ◽  
Performance Study ◽  
Analysis Software ◽  
Element Analysis ◽  
Test Standards ◽  
The Finite Element Analysis ◽  
Crashworthiness Design ◽  
Different Thickness

Based on the RCAR test standards, this paper analyzed the low-speed bumper tests regulations, proposed the design principles of the crash-box and identified the key parameters to evaluate the crashworthiness of the crash-box. This paper built the crash finite element models of the front bumper system, used the finite element analysis software LS-DYNA and HYPERWORKS to simulate the crashworthiness of the crash-box based on different thickness models and completed the performance study of the crash-box. The optimized crash-box has good crashworthiness and it will provide important guidance to the crash-box design.

Mechanical Properties Analysis of Steel-Timber Combined Member

2011 ◽  
Vol 347-353 ◽  
pp. 4093-4096
Author(s):  
Fu Ting Pan ◽  
Lei Kou ◽  
Cheng Yu Wang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Member ◽  
Finite Element Models ◽  
Element Analysis ◽  
Steel Core ◽  
The Finite Element Analysis ◽  
Finite Element Package ◽  
Analysis Models

Steel-timber combined member is a new kind of structural member composed of steel core and timber facing with bolt joint.This paper established the finite element analysis models of cantilever beam, and the finite element models were analyzed by the finite element package ANSYS considering the material and geometrically nonlinear.The results were compared with experimental results.Good mechanical properties were verified with comparison between data abtained from the test and calculated results.

Computational Modeling for the Dynamic Simulation of Paper and its Application to Some Paper Handling Problems

1998 ◽  
Author(s):  
Shinya Sekimoto ◽  
Makoto Ukai
Keyword(s):  
Finite Element ◽  
Rigid Wall ◽  
The Self ◽  
Bending Test ◽  
Flexible Plate ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Linear Finite Element ◽  
The Finite Element Analysis ◽  
Simulation Results

Abstract This paper deals with the paper handling problems in highspeed labor saving machines. Non-linear finite element analyses are done for a lightweight and flexible plate or beam leaping from a sliding constraint and colliding against a rigid wall. The fluid force of air and the paper elasticity are taken into account. The elastic property of paper is identified by comparing the “self-bending test” and the finite element analysis. The effect of geometrical stiffness with an initial deformation is studied. The change of the flying orbit is shown with flat paper and geometrically stiffened paper. The behavior of paper after colliding against a rigid wall is also simulated with the parameters of the paper velocity and the friction coefficient between the paper and the wall. The simulation results agree well with the designers’ experiences and help the designers design new machines with higher speed.

Mechanical Properties Research of Planar K-Joint

2015 ◽  
Vol 1091 ◽  
pp. 83-87
Author(s):  
Xi Bing Hu ◽  
Fei Hua Yi ◽  
Da Long Zhang ◽  
Hui Mao
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Models ◽  
Analysis Software ◽  
Joint Region ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Rotational Deformation ◽  
Increasing Load

The finite element models of the planar K-joint are established based on the finite element analysis software ANSYS. The bracing members are under the action of axial force and moment. Different rotational deformation values of the joint with different geometric parameters are reached with calculation and analysis. Results show that the deformation value approximate linearly increased with the increasing load of the bracing member. It also shows that the influence of the bracing member diameter and wall thickness is larger on rotational deformation values and the rotational deformation of the part of the K-joint is greatly influenced by the deformation of joint region.

Influence of Vertebra Stiffness in the Finite Element Analysis of the Intervertebral Disc

2012 ◽  
Author(s):  
Carlos A. Díaz ◽  
Jose J. García ◽  
Christian M. Puttlitz
Keyword(s):  
Finite Element ◽  
Intervertebral Disc ◽  
Complex Geometry ◽  
Rigid Bodies ◽  
Finite Element Models ◽  
Stress Distributions ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Low Stiffness ◽  
Computational Resources

Spine finite element models are an essential tool to study the degeneration of the intervertebral disc (IVD). Due to the complex geometry of the vertebras, the anisotropy and heterogeneity of the tissues, and the contact and material nonlinearities [1], spine models demand high computational resources. Considering the relatively low stiffness of the IVD compared to that of the vertebrae, we hypothesized that finite element stress and stress distributions of the IVD do not change substantially if the vertebras are modeled as rigid bodies. This simplification in spine models may considerably reduce the solution time when the interest is the analysis of the IVD.

scholarly journals Determining the exponent of the unloading curve when flattening a sphere

2020 ◽  
Vol 329 ◽  
pp. 03066
Author(s):  
Petr Ogar ◽  
Elena Ugryumova ◽  
Denis Gorokhov
Keyword(s):  
Finite Element ◽  
Residual Deformation ◽  
Spherical Segment ◽  
Finite Element Models ◽  
Rigid Surface ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Kinetic Indentation ◽  
Range Of Values ◽  
Space Property

To study the flattening of the sphere, it is proposed to use the kinetic indentation diagram by the plane. Given the known values of the reduced elastic modulus, applied force, maximum and residual deformation, it is possible to determine the contact area. It is indicated that in this regard, the exponent of the unloading curve of a pre-loaded sphere with a flat rigid surface plays an important role. The analysis of methods for determining the unloading curves of unloading for the finite element models, taking into account strain hardening, is carried out. It is shown that dependences of the unloading curves during flattening on the relative indentation in the form and the range of values differ from the similar ones during indentations of the sphere. The dependence between the exponents of the unloading curves for the force and for the area is determined. The range of correct use of the results of the finite element analysis of a hemisphere for rough surfaces is indicated. The exponent of the unloading curve after flattening the spherical segment from the half-space property is determined.

scholarly journals Experimental Finite Element Approach for Stress Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Ahmet Erklig ◽  
M. Akif Kütük
Keyword(s):  
Finite Element ◽  
Experimental Models ◽  
Finite Element Models ◽  
Nonlinear Case ◽  
Element Analysis ◽  
Mesh Structure ◽  
Numerical Studies ◽  
The Finite Element Analysis ◽  
Element Approach ◽  
Good Agreement

This study aims to determining the strain gauge location points in the problems of stress concentration, and it includes both experimental and numerical results. Strain gauges were proposed to be positioned to corresponding locations on beam and blocks to related node of elements of finite element models. Linear and nonlinear cases were studied. Cantilever beam problem was selected as the linear case to approve the approach and conforming contact problem was selected as the nonlinear case. An identical mesh structure was prepared for the finite element and the experimental models. The finite element analysis was carried out with ANSYS. It was shown that the results of the experimental and the numerical studies were in good agreement.

A Finite Element Analysis of the General Rolling Contact Problem for a Viscoelastic Rubber Cylinder

1988 ◽  
Vol 16 (1) ◽  
pp. 18-43 ◽  
Author(s):  
J. T. Oden ◽  
T. L. Lin ◽  
J. M. Bass
Keyword(s):  
Finite Element ◽  
Variational Principles ◽  
Standing Waves ◽  
Rolling Contact ◽  
Finite Element Models ◽  
Viscoelastic Cylinder ◽  
Element Analysis ◽  
Elastic Rubber ◽  
Frictional Effects ◽  
Rough Foundation

Abstract Mathematical models of finite deformation of a rolling viscoelastic cylinder in contact with a rough foundation are developed in preparation for a general model for rolling tires. Variational principles and finite element models are derived. Numerical results are obtained for a variety of cases, including that of a pure elastic rubber cylinder, a viscoelastic cylinder, the development of standing waves, and frictional effects.

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