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.

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.

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.

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.

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.

Submarine Slope Stability Evaluation Based on Strength Reduction Finite Element Method

2013 ◽  
Vol 423-426 ◽  
pp. 1325-1329
Author(s):  
Jin Feng Cao ◽  
Xiao Jie Jin ◽  
Jia Gang Li ◽  
Guang Hai Hu
Keyword(s):  
Finite Element ◽  
Slope Stability ◽  
Energy Demand ◽  
Equivalent Plastic Strain ◽  
Element Model ◽  
Strength Reduction ◽  
Stability Evaluation ◽  
Submarine Slide ◽  
Submarine Slope ◽  
Finite Element Software

Submarine landslide can destroy various engineering facilities. So, submarine slope stability evaluation is not only an important link of the construction safety guarantee and soil mechanics in the new field of ocean direction, but also the development of energy demand. Based on the finite element software Abaqus, the strength reduction method has been introduced to submarine slope stability evaluation. With the same finite element model, the safety factors of the land slope and submarine slope are respectively 1.82, 1.83, and 1.205, 1.215, using two criterions such as run-through of plastic zone and run-through of the equivalent plastic strain zone. The studies show that the submarine slide has the following characteristics: the displacement is 5~10 times larger than that of landslide; the obvious " uplift " and " collapse " phenomenon appears near the slope toe and the top of slope; the slide region is much more wider, deeper, less clearly slip shear zone boundary.

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.

Effect of Dissociation of Gas Hydrate on the Stability of Submarine Slope

2012 ◽  
Author(s):  
Zhongsheng Xiong ◽  
Jianhong Zhang
Keyword(s):  
Pore Pressure ◽  
Water Depth ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Embedment Depth ◽  
Human Beings ◽  
Submarine Slide ◽  
Submarine Slope ◽  
The Stability ◽  
Pressure Changes

Gas hydrate is a promising energy source because of its great storage under the sea. However, it is not easy to exploit as it becomes unstable and is easy to dissociate when it is disturbed and may trigger a submarine slide and cause a great impact to the safety of human beings and facilities in the sea. In this paper, changes of strength and pore pressure in a soil caused by the dissociation of gas hydrates are discussed. The shear strength of the soil containing gas hydrates decreases significantly with the dissociation of gas hydrates, which reduce the safety factor of a slope but not sufficient to cause failure. During a quick dissociation of gas hydrates in soil, gas or water in pores can hardly escape, and the released gas is greatly compressed and the pore pressure can be calculated. The strength and the pore pressure changes were considered in an infinite slope model. The result shows that only a small amount of gas hydrates has dissociated before the failure of the slope occurs. It is the increasing pore pressure rather than the reduction of soil strength that causes the failure of the slope. Parametric study was also carried out on gradient of slope, water depth and embedment depth of gas hydrates in the seabed. It was found that the gradient of a submarine slope is not an important factor to the failure of the slope while the water depth and the embedment depth affect the stability of the slope significantly.

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