Deformations and Stresses in Soft Body Tissues of a Sitting Person

1978 ◽  
Vol 100 (2) ◽  
pp. 79-87 ◽  
Author(s):  
W. W. Chow ◽  
E. I. Odell
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Surface Friction ◽  
Element Model ◽  
The Finite Element Method ◽  
Decubitus Ulcers ◽  
Surface Pressure Distribution ◽  
Body Tissues ◽  
Von Mises ◽  
Von Mises Stresses

This paper investigates the deformations and stresses in the buttocks of a person when he sits on a cushion. The study is motivated by the need for a better understanding of the design of wheelchair cushions and the prevention of decubitus ulcers. The finite element method is used on an axisymmetric model. Surface pressure distribution, surface friction, hydrostatic pressures and von Mises stresses are obtained. The finite element model reveals the three-dimensional state of stress at all internal locations for a typical human body. Thus the study complements the experimental measurements performed by many physicians and bioengineers.

scholarly journals Effect of Augmentation Material Stiffness on Adjacent Vertebrae after Osteoporotic Vertebroplasty Using Finite Element Analysis with Different Loading Methods

2015 ◽  
Vol 6;18 (6;11) ◽  
pp. E1101-E1110
Author(s):  
Ah-Reum Cho
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bone Cement ◽  
Vertebral Fractures ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Adjacent Vertebral Body ◽  
Von Mises ◽  
Von Mises Stresses

Background: Vertebroplasty is an effective treatment for osteoporotic vertebral fractures, which are one of the most common fractures associated with osteoporosis. However, clinical observation has shown that the risk of adjacent vertebral body fractures may increase after vertebroplasty. The mechanism underlying adjacent vertebral body fracture after vertebroplasty is not clear; excessive stiffness resulting from polymethyl methacrylate has been suspected as an important mechanism. Objectives: The aim of our study was to compare the effects of bone cement stiffness on adjacent vertebrae after osteoporotic vertebroplasty under load-controlled versus displacementcontrolled conditions. Study Design: An experimental computer study using a finite element analysis. Setting: Medical research institute, university hospital, Korea. Methods: A three-dimensional digital anatomic model of L1/2 bone structure was reconstructed from human computed tomographic images. The reconstructed three-dimensional geometry was processed for finite element analysis such as meshing elements and applying material properties. Two boundary conditions, load-controlled and displacement-controlled methods, were applied to each of 5 deformation modes: compression, flexion, extension, lateral bending, and torsion. Results: The adjacent L1 vertebra, irrespective of augmentation, revealed nearly similar maximum von Mises stresses under the load-controlled condition. However, for the displacementcontrolled condition, the maximum von Mises stresses in the cortical bone and inferior endplate of the adjacent L1 vertebra increased significantly after cement augmentation. This increase was more significant than that with stiffer bone cement under all modes, except the torsion mode. Limitations: The finite element model was simplified, excluding muscular forces and incorporating a large volume of bone cement, to more clearly demonstrate effects of bone cement stiffness on adjacent vertebrae after vertebroplasty. Conclusion: Excessive stiffness of augmented bone cement increases the risk of adjacent vertebral fractures after vertebroplasty in an osteoporotic finite element model. This result was most prominently observed using the displacement-controlled method. Key words: Bone cements, displacement-controlled method, finite element analysis, loadcontrolled method, osteoporosis, osteoporotic fracture, polymethyl methacrylate, vertebroplasty

A Finite Element Analysis of the Human Temporomandibular Joint

1994 ◽  
Vol 116 (4) ◽  
pp. 401-407 ◽  
Author(s):  
J. Chen ◽  
Liangfeng Xu
Keyword(s):  
Finite Element ◽  
Temporomandibular Joint ◽  
Reaction Force ◽  
Element Model ◽  
Contact Stresses ◽  
Element Analysis ◽  
Tensile Stresses ◽  
Reaction Forces ◽  
Von Mises ◽  
Von Mises Stresses

A 2-D finite element model of the human temporomandibular joint (TMJ) has been developed to investigate the stresses and reaction forces within the joint during normal sagittal jaw closure. The mechanical parameters analyzed were maximum principal and von Mises stresses in the disk, the contact stresses on the condylar and temporal surfaces, and the condylar reactions. The model bypassed the complexity of estimating muscle forces by using measured joint motion as input. The model was evaluated by several tests. The results demonstrated that the resultant condylar reaction force was directed toward the posterior side of the eminence. The contact stresses along the condylar and temporal surfaces were not evenly distributed. Separations were found at both upper and lower boundaries. High tensile stresses were found at the upper boundaries. High tensile stresses were found at the upper boundary of the middle portion of the disk.

Vertical tail FEA with a CAD/CAE based multidisciplinary process

2018 ◽  
Vol 90 (4) ◽  
pp. 652-658
Author(s):  
Péter Deák
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Tail Length ◽  
Element Model ◽  
Point Of View ◽  
Content Type ◽  
Nodal Displacements ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Aided Design

Purpose The purpose of this paper is to make an analytical comparison of two vertical tail models from a structural point of view. Design/methodology/approach The original vertical tail design of PZL-106BT aircraft was used for Computer aided design (CAD) modeling and for creating the finite element model. Findings The nodal displacements, Von-Mises stresses and Buckling factors for two vertical tail models have been found using the finite element method. The idea of a possible Multidisciplinary concept assessment and design (MDCAD) concept was presented. Practical implications The used software analogy introduces an idea of having an automated calculation procedure within the framework of MDCAD. Originality/value The aircraft used for calculation had undergone a modification in its vertical tail length, as there was an urgent need to calculate for the plane’s manufacturer, PZL Warszawa – Okecie.

Finite Element Analysis of Gold Bonding under Different Loading Conditions

2014 ◽  
Vol 607 ◽  
pp. 713-716
Author(s):  
Wen Liang Tang ◽  
Chun Yue Huang ◽  
Tian Ming Li ◽  
Ying Liang ◽  
Guo Ji Xiong ◽  
...  
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Simulation Software ◽  
Bonding Time ◽  
Von Mises Stress ◽  
Bonding Pressure ◽  
Element Analysis ◽  
Von Mises ◽  
Three Dimensional Finite Element

In this paper, ANSYS-LSDYNA simulation software is used to build the three-dimensional finite element model of the ball bond and to get the Von Mises stress. The change of stress about the bump is researched which base on the model in different bonding pressure, bonding power and bonding time. The result show that: The stress increase with bonding pressure increase within a certain bonding pressure range, and then the stress will maintain a table number, however, the stress will continue to increase when the bonding pressure reach a certain value; increasing the bonding power, the area of lager stress will grow; prolonging the bonding time, the stress of the pad will increase with time, but when time increase to a certain value, the stress of the pad will not increase over time.

The Application of Multi-Wedge Cross Wedge Rolling Forming Long Shaft Technology

2011 ◽  
Vol 101-102 ◽  
pp. 1002-1005 ◽  
Author(s):  
Jing Zhao ◽  
Li Qun Lu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Model ◽  
Rolling Mill ◽  
Three Dimensional ◽  
Element Model ◽  
Solid Model ◽  
The Finite Element Method ◽  
Cross Wedge Rolling ◽  
The Finite Element Model

The process of multi-wedge cross wedge rolling is an advanced precision technology for forming long shaft parts such as automobile semi-axes. Three-dimensional solid model and the finite element model of semi-axes on automobile and dies of its cross wedge rolling were established. The process of cross wedge rolling was simulated according to the actual dimension of semi-axes on automobile utilizing the finite element method (FEM)software ANSYS/LS-DYNA. The required force parameters for designing semi-axes mill are determined. The appropriate roller width was determined according to the length and diameter of semi-axes on automobile. The results have provided the basis for the design of specific structure of automobile semi-axes cross wedge rolling mill.

scholarly journals Assessment of stress changes in dentoalveolar and skeletal structures of the mandible with the miniplate anchored Forsus: A three-dimensional finite element stress analysis study

2017 ◽  
Vol 7 ◽  
pp. 87-93
Author(s):  
Harshal Ashok Patil ◽  
Pawankumar Dnyandeo Tekale ◽  
Veerendra V. Kerudi ◽  
Jitendra S. Sharan ◽  
Ratnadip Arunrao Lohakpure ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Von Mises Stress ◽  
Functional Appliance ◽  
3D Finite Element ◽  
Fixed Functional Appliance ◽  
Finite Element Stress Analysis ◽  
Von Mises

ObjectiveThe study conducted to assess the effects of a fixed functional appliance (Forsus Fatigue Resistant Device; 3M Unitek, Monrovia, CA, USA) on the mandible with three-dimensional (3D) finite element stress analysis.Materials and MethodsA 3D finite element model of mandible with miniplate at mandibular symphysis was prepared using SolidEdge software along with the plate geometry. The changes were deliberated with the finite element method, in the form of highest von Mises stress and maximum principal stress regions.ResultsMore areas of stress were seen in the model of the mandible at cortical bone in canine region at bone and miniplate interface.ConclusionsThis fixed functional appliance studied by finite element model analysis caused more von Mises stress and principal stress in both the cortical bone and the condylar region.

scholarly journals Stress distribution in a mandibular premolar after separated nickel-titanium instrument removal and root canal preparation: a three-dimensional finite element analysis

2019 ◽  
Vol 47 (4) ◽  
pp. 1555-1564 ◽  
Author(s):  
Na Ni ◽  
Jing Ye ◽  
Liyuan Wang ◽  
Simin Shen ◽  
Lei Han ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Cervical Region ◽  
Element Analysis ◽  
Straight Line ◽  
Mandibular First Premolar ◽  
Von Mises ◽  
Von Mises Stresses

Objective This study used finite element analysis (FEA) to assess the von Mises stresses of a mandibular first premolar after removing a separated instrument with an ultrasonic technique. Methods FEA models of the original and treated mandibular first premolar were reconstructed, and three models (the original canal, size 30/taper 0.04 canal, and separated instrument removal canal) were created. Two-direction (vertical and lateral) loading patterns were simulated with a 175-N force. The maximum von Mises stresses of the models within the roots from the apex to the cervical region were collected and summarized. Results Under vertical and lateral loads, all maximal values in the three models were localized in the straight-line access region. Compared with the original model (model 1), the treated models (models 2 and 3) had greater maximum stress values from the apex to the cervical region. Greater differences in the maximum von Mises stresses between models 2 and 3 were present in the straight-line access region. Conclusions Separated instrument removal caused changes in stress distribution and increases in stress concentration in the straight-line access region of roots.

Three-Dimensional Thermo-Mechanical Finite Element Simulation for Casting Ladle Structure under Thermal Loadings

2008 ◽  
Vol 575-578 ◽  
pp. 1-6
Author(s):  
Shou Ju Li ◽  
Ying Xi Liu ◽  
He Yu
Keyword(s):  
Finite Element ◽  
Shell Structure ◽  
Yield Criterion ◽  
Three Dimensional ◽  
Element Model ◽  
Steel Shell ◽  
Casting Ladle ◽  
Lining Structure ◽  
Calculation Results ◽  
Von Mises

The finite element model of coupling the thermal field with structural analysis is proposed in order to analyze the thermo-stress of casting ladle structure. The thermal fields of casting ladle with refractory lining structure are computed according to the thermal properties of materials and boundary conditions. Numerical simulation shows that that computed outer temperatures of casting ladle agree with measured ones. The thermo-stress of casting ladle structure is simulated by taking thermal loadings as the loading conditions of the steel shell structure. Material behaviors were described by the Drucker–Prager plasticity model and Von Mises yield criterion. Calculation results of thermo-stress fields shows the outer shell structure is safety under the action of thermal loadings.

Finite Element Analysis for the Mega Columns for XRL West Kowloon Terminus

2013 ◽  
Vol 405-408 ◽  
pp. 1139-1143
Author(s):  
Wei Su ◽  
Ying Sun ◽  
Shi Qing Huang ◽  
Ren Huai Liu
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Parametric Design ◽  
Three Dimensional ◽  
Element Model ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Von Mises ◽  
Three Dimensional Finite Element

Using ANSYS parametric design language, a three-dimensional finite element model is developed to analyze the stress distribution and the strength of the mega columns for XRL West Kowloon Terminus. The detailed von Mises stress distribution in each column, vertical stiffener plates and the diaphragm plates is obtained. From the analysis, the phenomenon of stress concentration is obvious in both upper and lower diaphragm plates. The local value of von Mises stress in them is higher than the yield stress value, which must be avoided by more detailed local structural design.

Investigation into the Effect of the Nut Thread Run-Out on the Stress Distribution in a Bolt Using the Finite Element Method

2003 ◽  
Vol 125 (3) ◽  
pp. 527-532 ◽  
Author(s):  
J. W. Hobbs ◽  
R. L. Burguete ◽  
E. A. Patterson
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Element Model ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Dimensional Models ◽  
Three Dimensional Models

By means of comparing results from finite element analysis and photoelasticity, the salient characteristics of a finite element model of a nut and bolt have been established. A number of two-dimensional and three-dimensional models were created with varying levels of complexity, and the results were compared with photoelastic results. It was found that both two-dimensional and three-dimensional models could produce accurate results provided the nut thread run-out and friction were modeled accurately. When using two-dimensional models, a number of models representing different positions around the helix of the thread were created to obtain more data for the stress distribution. This approach was found to work well and to be economical.

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