scholarly journals Does the Screw Position in the ACDF Affect the Degeneration of Adjacent Segments? A Three-Dimensional Finite Element Analysis

2020 ◽  
Author(s):  
Kai Guo ◽  
Jiawei Lu ◽  
Ziqi Zhu ◽  
Beiduo Shen ◽  
Tongde Wu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Intervertebral Disc ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Adjacent Segment ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Abstract Background: ACDF is the main treatment of cervical disease. Adjacent Segment Degeneration (ASD) is the main complication of long-term follow-up of ACDF. we conduct a detailed study of ACDF by means of three-dimensional finite element analysis and find the effect of screw placement and location on the occurrence of ASD.Methods: The cervical computed tomography (CT) data (layer thickness of 0.625 mm) for a 30-year-old healthy male volunteer was collected. All the data were combined to create a C2-7 3D finite element model using Abaqus software. Based on the data and the actual surgical maneuver, a screw positioning model was established, in order to observe the cervical range of motion (ROM) with different positions of screw, as well as the pressure change of the adjacent segment intervertebral disc.Results: The proposed finite element model of cervical spine was effective, and ROM on all directions of C4-C6 segments changed after ACDF surgery. Under the same torque settings, compared with the control group, C2/3 segment rotational ROM increased; C2/3, C3/4 segments lateral flexion ROM also increased. Regarding the influence of screw positioning, it has limited influence on the ROM and The intervertebral disc pressure (IDP), and compared with different horizontal positions, different vertical positions imposed greater influence on the ROM and IDP. Conclusions: For ACDF surgery, positioning the screw at the anterior inferior part of the cervical vertebral body could provide more natural cervical ROM and the least IDP, while maintaining high biomechanical stability, and is more in line with human biomechanical requirements.

Parametric Analysis Mechanical Properties of Bolted Joints

2010 ◽  
Vol 97-101 ◽  
pp. 3924-3927 ◽  
Author(s):  
Da Zhao Yu ◽  
Yue Liang Chen ◽  
Zhong Hu Jia ◽  
Yong Gao ◽  
Wen Lin Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Three-dimensional finite element model of a bolted joint has been developed in the non-linear finite element code MSC.Marc and attempts were made to validate it by comparing results with those of experiments and other finite element. Issues in modeling the contact between the joint parts, which affect the accuracy and efficiency of the model, were presented. Experimental measurements of surface strains and load transfer ratio(LTR) were compared with results from finite element analysis. The results show that three-dimensional finite element model of bolted joint can produce results in close agreement with experiment. Three-dimensional effects such as bolt titling, seconding and through-thickness variations in stress and strain are well represented by such models. Three-dimensional finite element analysis was also used to study the effects of different parameters on the mechanical behaviour of single lap bolted joints. The results show that straight hole, small bolt diameter, and big hole pitch are selected first for bolted joint if other conditions allowed, and effect of bolt material on LTR of joint is small for small load. Interference and pre-stress should be strictly controlled for bolted joints in order to attain the best fatigue capability of lap joint.

Three-Dimensional Finite Element Analysis of Mixed-Mode Interfacial Delamination for the Pull-Off Test

2007 ◽  
Author(s):  
Zuo Sun ◽  
David A. Dillard
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Mixed Mode ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Interfacial Delamination ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A three-dimensional nonlinear finite element analysis model is presented to study mixed-mode interfacial delamination for a pull-off test consisting of a thin film strip debonded from a glass substrate. Since the strain energy release rates of all three modes (Mode I, Mode II, and Mode III) and the mode mixities vary along the width of the debond front, prediction of the in-situ shape of the debond front remains an interesting and challenging topic. A cohesive zone model is incorporated into the three-dimensional finite element model to predict the interfacial crack propagation profile for the film deformation regime ranging from bending plate to stretching membrane. This three-dimensional finite element model is found to provide additional insights for interfacial delamination for the pull-off test.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

INVESTIGATION OF DAMAGE ON DERBENDIKHAN DAM DURING EARTHQUAKE EXCITATION

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Cagri Mollamahmutoglu ◽  
Idris Bedirhanoglu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Main Body ◽  
Damage Development ◽  
Element Analysis ◽  
Rock Fill ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this study, the performance of a damaged dam was evaluated through a three-dimensional finite element model. The dam is located in Derbendikhan city of Northern Iraq and damaged during a 7.3 magnitude earthquake which was happened 30 kilometers south of Halabja city. Derbendikhan dam which was built between the years 1956-1961 is a clay-core rock fill dam. The damage of the dam was investigated at the site right after the earthquake and some cracks were observed in the main body of the dam. The main goal of this work is to present the results of the survey which was conducted at the site and investigating the damage development mechanism through a realistic three-dimensional finite element model of the dam. As complying with the observations at the site, the finite element analysis has shown that the primary failure mechanism is due to the separation of the core and rock fill sections at the downstream side of the dam.

Load Transfer Analysis of Cracked Bolted Joints

2010 ◽  
Vol 118-120 ◽  
pp. 147-150
Author(s):  
Da Zhao Yu ◽  
Yue Liang Chen ◽  
Yong Gao ◽  
Wen Lin Liu ◽  
Zhong Hu Jia
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Load Transfer ◽  
Three Dimensional ◽  
Element Model ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Three-dimensional finite element model of a cracked bolted joint has been developed in the non-linear finite element code MSC.Marc and attempts were made to validate it by comparing results with those of experiments and other finite element. Issues in modeling the contact between the joint parts, which affect the accuracy and efficiency of the model, were presented. Experimental measurements of load transfer were compared with results from finite element analysis. The results show that three-dimensional finite element model of cracked bolted joint can produce results in close agreement with experiment. Three-dimensional effects such as bolt titling, seconding and through-thickness variations in stress and strain are well represented by such models. Three-dimensional finite element analysis was also used to study the effects of hole mod and crack on the load transfer behaviour of single lap bolted joints. The results show that hole mode has big effect on load transfer of cracked bolted joint. In the whole progress of crack growth, the load transfer through bolt 1 decrease, and almost all of the load duduction of bolt 1 transfer into blot 2 rather than into bolt 3.

scholarly journals A Finite Element Analysis of Sacroiliac Joint Displacements and Ligament Strains in Response to Three Manipulations

2020 ◽  
Author(s):  
Zhun Xu ◽  
Yikai Li ◽  
Shaoqun Zhang ◽  
Liqing Liao ◽  
Kai Wu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Sacroiliac Joint ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Ligament Strain ◽  
Dimensional Finite Element ◽  
The Right ◽  
Three Dimensional Finite Element

Abstract Background: Clinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes. However, the specific mechanisms of manipulations are still unclear. The purpose of this study was to investigate the effects of three common manipulations on the pressures and displacements of SIJ, and the strains of the surrounding ligaments. Methods: A three-dimensional finite element model of the pelvis-femur was developed. The manipulation of hip and knee flexion (MHKF), the manipulation of oblique pulling (MOP), and the manipulation of lower limb hyperextension (MLLH) were simulated. The pressures and displacements of SIJs, and the strains of the surrounding ligaments were analyzed under the three manipulations. Results: The MOP produced the greatest pressure on the left SIJ, at 6.6 MPa, while the MHKF could produce the lowest pressure on the right SIJ, at 1.5 MPa. The displacements of SIJs were all less than 1mm in the three manipulations. The three manipulations could cause different degrees of the strains of ligaments around the SIJs, and the MOP could produce the largest strain of ligaments. Conclusion: The three manipulations all produced small displacements of SIJs, while they caused different degrees of ligament strains, which might be the reason for relieving the SIJ pain. The MOP may be a more effective manual therapy. Key words: Manipulation, Sacroiliac joint, Displacement, Ligament strain, Finite element analysis.

Precision Machines: Diagnostics of Vibration Through Modal and Finite Element Analysis

1991 ◽  
Author(s):  
V. Prakash ◽  
R. J. Montague
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Test Model ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Structure Correlation ◽  
Three Dimensional Finite Element ◽  
Precision Machines

Abstract This paper presents the diagnostics of the effects of vibration on the precise placement of electronic components in a surface mount assembly process. Experimental Modal Analysis using present day software/hardware as well as a three dimensional finite element model are performed on the machine structure. Correlation between the experiment and finite element model are also performed and the strength of using the finite element model as a test model for contemplating any design alterations are presented.

scholarly journals Structural Optimization of Road Fully Enclosed Sound Barrier Based on Three-Dimensional Finite Element Analysis

2021 ◽  
Vol 1210 (1) ◽  
pp. 012002
Author(s):  
Yang jingqiang ◽  
Din dewei ◽  
Yang zhimian
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Sound Barrier ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Elevated Road ◽  
Three Dimensional Finite Element

Abstract With the help of the finite element analysis software ANSYS, this paper establishes a finite element model of a fully enclosed sound barrier of elevated road, calculating and analyzing the stress of supporting structure under different working conditions, checking the strength, stiffness and stability of the structure under the most unfavorable working condition. Finally we optimize the structure according to its characteristics.

Evaluation of sternum closure methods by means of a nonlinear finite element analysis

2019 ◽  
Vol 233 (12) ◽  
pp. 1282-1291 ◽  
Author(s):  
Suleyman Nazif Orhan ◽  
Mehmet Hamit Ozyazicioglu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Plastic Material ◽  
Steel Wire ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Computed Tomography Images ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The main purpose of this study is to develop a validated three-dimensional finite element model of sternum closure techniques. For this aim, the finite element method analysis results of three closure methods were compared with experimental test results. Also, three more closure techniques are simulated numerically to study the effect of the number of wires used in the manubrium and xiphoid regions. A three-dimensional model of polyurethane sternum foam was created based on computed tomography images. Six different closure techniques using steel wire, steel bands and ZipFix bands were modeled on the sternum and transferred into a three-dimensional finite element model. The sternum was modeled as an isotropic bilinear-elasto-plastic material, and nonlinear contact conditions were applied. The models were analyzed under lateral distraction loading, and load-displacement curves were obtained from displacements at the incision line. Allowable loads and stiffness values of the methods were evaluated from these curves. The results showed the importance of the including material as well as geometric nonlinearities in the simulations to obtain realistic results from the numerical analyses. Also, the analyses showed that closures that include steel or ZipFix bands are superior to conventional wiring, and addition of a single wire at the manubrium and xiphoid regions significantly improved the efficiency of the closure techniques.

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