Finite Element Analysis of Fixation System Influence on the Thoracolumbar Spine Stability

2016 ◽  
Vol 821 ◽  
pp. 685-692 ◽  
Author(s):  
Klaudia Szkoda ◽  
Celina Pezowicz
Keyword(s):  
Finite Element ◽  
Sagittal Plane ◽  
Thoracolumbar Spine ◽  
Element Model ◽  
Intervertebral Discs ◽  
Vertebral Compression Fractures ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Transpedicular Fixation ◽  
The Stability

All segments of the spine are characterized by a corresponding curvature in the sagittal plane and different geometrical parameters of vertebrae, which affects the complicated structure of transition between subsequent segments. The aim of the study was to assess changes occurring in the thoracolumbar spine, as a result of application of the transpedicular fixation. The research was conducted on finite element model, which was constructed on the basis of CT images. Five different configurations of the model were analyzed: focusing on vertebral compression fractures and degeneration of intervertebral discs. The analysis showed that the highest displacement occurred for a segment with intervertebral disc degeneration. Transpedicular fixation of injured thoracolumbar spine is given the opportunity to improve the stability and stiffness of the segment under consideration.

FINITE ELEMENT ANALYSIS OF A DENTAL IMPLANT

2003 ◽  
Vol 15 (02) ◽  
pp. 82-85 ◽  
Author(s):  
SHYH-CHOUR HUANG ◽  
CHANG-FENG TSAI
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Element Model ◽  
Element Analysis ◽  
3 Dimensional ◽  
Dimensional Finite Element ◽  
The Stability ◽  
Stress Concentration Effect ◽  
Implant System

This paper presents results from using a 3-dimensional finite element model to assess the stress distribution in the bone, in the implant and in the abutment as a function of the implant's diameter and length. Increasing implant diameter and length increases the stability of the implant system. By using a finite element analysis, we show that implant length does not decrease the stress distribution of either the implant or the bone. Alternatively, however implant diameter increases reduce the stresses. For the latter case, the contact area between implant and bone is increased thus the stress concentration effect is decreased. Also, with increased implant diameter the bone loss is decreased and as a consequence the success rate is improved.

Finite Element Analysis on Stability for Elastic-Jumping Membrane

2011 ◽  
Vol 287-290 ◽  
pp. 717-722 ◽  
Author(s):  
Zhen Ting Wu ◽  
Shun Jiang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Critical Load ◽  
Element Model ◽  
Structure Parameter ◽  
Element Analysis ◽  
Factors Influencing ◽  
Optimizing Design ◽  
Main Factors ◽  
The Stability

In order to increase the designing precision and study the main factors influencing the stability of metal elastic-jumping membrane, a set of experimental equipments have been designed to test the stability of metal elastic-jumping membrane. The laws of influencing the stability of elastic-jumping membrane were studies by changing the thickness, high, radius etc structure parameter. It shows that the increasing of high and thickness can enhance the distortion rigidity of metal elastic-jumping membrane, result in the increase of critical load at losing stability; the increasing of diameter can reduce the distortion rigidity of metal elastic-jumping membrane, result in the decrease of critical load at losing stability. At the same time, the correctness of finite element model was confirmed, and the basis was established for finite element method applying in optimizing design of metal elastic-jumping membrane.

Structural Finite Element Analysis on Side Wall Pouring Formwork Trolley for Subway Station

2013 ◽  
Vol 380-384 ◽  
pp. 95-100
Author(s):  
Yan Fang Ma ◽  
Zhen Tong He ◽  
Qin Zhao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Light Condition ◽  
Side Wall ◽  
Element Model ◽  
Structure Design ◽  
Analysis Software ◽  
Element Analysis ◽  
Work Condition ◽  
The Stability

Structure finite element analysis software ANSYS is used to establish relatively complete finite element model for automatic side wall formwork trolley, analyze the stability of formwork trolley under light condition and work condition, and give a correct classification on working conditions of formwork trolley. Main factors influencing the stability of formwork trolley are found and improving measures are proposed to provide reference for optimal structure design and standardized design of formwork trolley.

Analysis of progressive deformation of the Edmonton Convention Centre excavation

1987 ◽  
Vol 24 (3) ◽  
pp. 430-440 ◽  
Author(s):  
D. H. Chan ◽  
N. R. Morgenstern
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Softening ◽  
Progressive Failure ◽  
Field Measurements ◽  
Shear Zones ◽  
Element Model ◽  
Progressive Deformation ◽  
Element Analysis ◽  
The Stability

A finite element analysis was performed of the deformations observed during the excavation of the Edmonton Convention Centre. Local geology in the Edmonton area consists of layers of shale with weak bentonite seams overlain by glacial deposits. The presence of the bentonite seams, which possess strain-softening characteristics, controls the stability of the excavation, which is located in a valley wall. To simulate the influence of the bentonite seams a strain-softening finite element model is used to estimate the amount of deformation in the foundation of the excavation. Field measurements indicated that localized progressive straining had occurred during the excavation process, and substantial heave of the foundation floor was observed. The finite element results show progressive deformation of the excavation and propagation of shear zones. Good agreement between the finite element results and the field observations is obtained. Key words: progressive failure, strain softening, finite element analysis, shear band, excavation stability.

scholarly journals The Effects of Physiological Biomechanical Loading on Intradiscal Pressure and Annulus Stress in Lumbar Spine: A Finite Element Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Siti Nurfaezah Zahari ◽  
Mohd Juzaila Abd Latif ◽  
Nor Raihanah Abdull Rahim ◽  
Mohammed Rafiq Abdul Kadir ◽  
Tunku Kamarul
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Three Dimensional ◽  
Element Model ◽  
Intervertebral Discs ◽  
Intradiscal Pressure ◽  
Element Analysis ◽  
Physiological Loading ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The present study was conducted to examine the effects of body weight on intradiscal pressure (IDP) and annulus stress of intervertebral discs at lumbar spine. Three-dimensional finite element model of osseoligamentous lumbar spine was developed subjected to follower load of 500 N, 800 N, and 1200 N which represent the loads for individuals who are normal and overweight with the pure moments at 7.5 Nm in flexion and extension motions. It was observed that the maximum IDP was 1.26 MPa at L1-L2 vertebral segment. However, the highest increment of IDP was found at L4-L5 segment where the IDP was increased to 30% in flexion and it was more severe at extension motion reaching to 80%. Furthermore, the maximum annulus stress also occurred at the L1-L2 segment with 3.9 MPa in extension motion. However, the highest increment was also found at L4-L5 where the annulus stress increased to 17% in extension motion. Based on these results, the increase of physiological loading could be an important factor to the increment of intradiscal pressure and annulus fibrosis stress at all intervertebral discs at the lumbar spine which may lead to early intervertebral disc damage.

Finite Element Analysis of Flexible Pipes Under Compression: Influence of the Sample Length

2015 ◽  
Author(s):  
Eduardo Ribeiro Malta ◽  
Clóvis de Arruda Martins
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
High Strength ◽  
Element Model ◽  
Sample Length ◽  
Flexible Pipe ◽  
Element Analysis ◽  
Flexible Pipes ◽  
The Stability

In order to study the compressive behavior of flexible pipes, a nonlinear tridimensional finite element model was developed. This model recreates a five layer flexible pipe with two tensile armor layers, an external polymeric sheath, an orthotropic high strength tape and a rigid inner nucleus. Using this model, several studies are being conducted to verify the influence of key parameters on the wire instability phenomenon. The pipe sample length can be considered one of these parameters and its variation causes significant change at the stability response of the tensile layers. This article includes a detailed description of the finite element model itself and a case study where the length of the pipe is changed. The procedure of this analysis is here described, along with the results.

Finite-element modelling of multilayer X-ray optics

2017 ◽  
Vol 24 (3) ◽  
pp. 717-724
Author(s):  
Xianchao Cheng ◽  
Lin Zhang
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Photon Flux ◽  
Attractive Alternative ◽  
Geometrical Parameters ◽  
X Rays ◽  
Element Analysis ◽  
Ray Optics ◽  
X Ray ◽  
Fea Model

Multilayer optical elements for hard X-rays are an attractive alternative to crystals whenever high photon flux and moderate energy resolution are required. Prediction of the temperature, strain and stress distribution in the multilayer optics is essential in designing the cooling scheme and optimizing geometrical parameters for multilayer optics. The finite-element analysis (FEA) model of the multilayer optics is a well established tool for doing so. Multilayers used in X-ray optics typically consist of hundreds of periods of two types of materials. The thickness of one period is a few nanometers. Most multilayers are coated on silicon substrates of typical size 60 mm × 60 mm × 100–300 mm. The high aspect ratio between the size of the optics and the thickness of the multilayer (107) can lead to a huge number of elements for the finite-element model. For instance, meshing by the size of the layers will require more than 1016 elements, which is an impossible task for present-day computers. Conversely, meshing by the size of the substrate will produce a too high element shape ratio (element geometry width/height > 106), which causes low solution accuracy; and the number of elements is still very large (106). In this work, by use of ANSYS layer-functioned elements, a thermal-structural FEA model has been implemented for multilayer X-ray optics. The possible number of layers that can be computed by presently available computers is increased considerably.

Study on Influence of Implant Thickness and Fixation Position on Implant Stability Using Finite Element Analysis

2011 ◽  
Vol 9 ◽  
pp. 47-55
Author(s):  
D. Devika ◽  
G. Arumaikkannu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bone Fractures ◽  
Element Model ◽  
Lateral Position ◽  
Implant Design ◽  
Orthopaedic Implant ◽  
Element Analysis ◽  
The Stability ◽  
As Stress

Patient anatomy specific orthopaedic implant design, fabrication and identification of the most suitable position to fix implants onto bone fractures are challenging problems for surgeons to overcome of the existing shortcomings of commercially available implants. In this work, a 3D finite element model of the left tibial bone of an adult male is developed from Computed Tomography scan images. Proximal tibial fracture type B1 (as per Association for the Study of Internal Fixation) is simulated on the bone model. A geometry specific implant is obtained in order to promote better bone ingrowths and uniform stress distribution, by extracting the surface features of the bone. Finite Element Analysis is performed to evaluate and compare the mechanical properties such as stress, strain and displacement of the bone and implant of four various thicknesses which are fixed at two different positions. The design objectives such as low stress and displacement combination is obtained through the antero-lateral position with 1.8 mm implant thickness. Various material properties are assigned to cortical, cancellous, trabecular regions of the bone and to implants made up of titanium alloy. The results obtained from the Finite Element Analysis are used to evaluate the stability and suitability of the implant for that particular fracture.

Large Displacement Finite Element Analysis of Submarine Slide due to Gas Hydrate Dissociation

2011 ◽  
Author(s):  
Jun Liu ◽  
Long Yu ◽  
Xianjing Kong ◽  
Yuxia Hu
Keyword(s):  
Finite Element ◽  
Gas Hydrate ◽  
Soil Layer ◽  
Element Model ◽  
Large Displacement ◽  
Element Analysis ◽  
Hydrate Dissociation ◽  
Submarine Slide ◽  
Submarine Slope ◽  
The Stability

Gas hydrate dissociation will reduce the stability of the submarine slope, which has been increasingly considered as a potential geohazard. In this study, a conventional geotechnical model is used to simulate gas hydrate dissociation while the thermal and geochemical effects are considered by reducing geotechnical strength parameters (c-φ) and stiffness (E). The stability analysis of submarine slope due to gas hydrate dissociation is carried out using the large displacement finite element model – RITSS (Remeshing and Interpolating Technique with Small Strain model). The strength and stiffness parameters of gas hydrates are reduced gradually after each remesh according to the strength-dissociation relationship. The large displacement analysis procedure considering dissociation is given and the effects of the thickness of the top normal soil layer on slope stability is discussed.

Sign in / Sign up

Export Citation Format

Share Document