Finite element model–based evaluation of tissue stress variations to fabricate corrective orthosis in feet with neutral subtalar joint

2016 ◽  
Vol 41 (2) ◽  
pp. 157-163
Author(s):  
Sathish Paul ◽  
Rekha Vijayakumar ◽  
Lazar Mathew ◽  
Sudesh Sivarasu
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Finite Element Model ◽  
Subtalar Joint ◽  
Three Dimensional ◽  
Element Model ◽  
Neutral Position ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Computed Tomography Images

Background: The subtalar joint position during static stance is a crucial determinant of the peak plantar pressures and forms ideal reference point for any intervention in foot-related problems for leprosy-affected patients. Objectives: The study pursued the hypothesis through a three-dimensional model that stress will be minimal in the distal joints of the foot when the subtalar joint is in neutral static stance position. Study design: Finite element model. Methods: The computed tomography images of the feet for five patients suffering from Hansen’s disease having no muscle weakness and joint restriction were acquired. The gray intensities corresponding to the bones of the foot from the computed tomography images were three-dimensionally reconstructed. The three-dimensional model of the human foot, incorporating the realistic geometry, and the material properties of the hard tissues were then analyzed using a finite element solver for the stress distribution on bones of the foot. Results: The results demonstrate that the position of the calcaneum in the static stance position does contribute to the varying stress in the foot. Conclusion: The stresses in the bones of the foot are minimal while the subtalar is in neutral position; this position will be suitable for foot orthotic fabrication. Clinical relevance The clinicians, therapists, and podiatrists having less engineering skills can quickly assess the patient and get optimal results on the stress associated with the joints of the foot.

Finite Element Simulation on Stress of Steel Sphere Shell

2012 ◽  
Vol 532-533 ◽  
pp. 297-300
Author(s):  
Chang Li Song ◽  
Jing Ji
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Steel Sphere ◽  
Element Simulation ◽  
Good Agreement

In order to verify correctness of two-dimensional axisymmetric finite element model, this paper carries out axial symmetry analysis of the steel ball shell by ANSYS software and 2-D finite element model is established. The radial and tangential stress distribution is acquired, through comparison with the theoretical solution, both are in good agreement. So it is feasible to simulate the three-dimensional model by finite element axisymmetrical two-dimensional model.

OS0510 Development of a finite element model of foamed plastics with X-ray computed tomography images

2013 ◽  
Vol 2013 (0) ◽  
pp. _OS0510-1_-_OS0510-2_
Author(s):  
Mai NONOGAWA ◽  
Yuya KOZUKA ◽  
Tsuyoshi NISHIWAKI ◽  
Yasumasa NAKANISHI ◽  
Takaya KOBAYASHI
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
X Ray ◽  
Computed Tomography Images ◽  
Foamed Plastics ◽  
X Ray Computed

Modal Analysis of Two Wheels Scooter Based on Solidworks

2014 ◽  
Vol 960-961 ◽  
pp. 1420-1423
Author(s):  
Zhi Dong Huang ◽  
Guo Fei Li ◽  
Juan Cong ◽  
Yun Wang ◽  
Wei Na Yu ◽  
...  
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Dynamic Design ◽  
Driving System ◽  
Set Up ◽  
The Finite Element Model

Based on Solidworks software, the three-dimensional model of two wheels scooter is set up. The finite element model of two wheels scooter is generated. Modal analysis of driving system and telescopic mechanism of bar on two wheels scooter is investigated. The first five orders natural frequency and major modes of driving system and telescopic mechanism of bar are clarified. The method and the result can be used as a reference of dynamic design and lay foundation for calculation and analysis of dynamic response for the two wheels scooter.

scholarly journals Analysis of historical structures by using finite element method in Iznik Yeşil Mosque

2019 ◽  
Vol 5 (4) ◽  
pp. 121
Author(s):  
Aykut Uray ◽  
Hasan Selim Şengel ◽  
Serdar Çarbaş
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Soil Survey ◽  
Three Dimensional Model ◽  
Historical Structures ◽  
Model Study ◽  
Non Destructive ◽  
The Finite Element Model

In this study, non-destructive tests and laboratory tests were carried out in order to determine the material properties in Iznik Yeşil Mosque, Iznik District, Bursa Province. For the purpose of determining the soil characteristics of the building, the soil survey studies conducted in the Iznik Yeşil Mosque area were investigated. The finite element model was formed by making a three dimensional model study of the structure. With the finite element model, static analysis, modal analysis and behavioral spectrum analysis were performed under vertical loads in order to collect data for the damaged areas of the structure.

Crushing of a Steel Tube Umbilical (STU) Cable During Laying Operation: A Finite Element Method Assessment at the Entry/Exit Regions of Tensioner Shoes

2020 ◽  
Author(s):  
William C. Guttner ◽  
Caio C. P. Santos ◽  
Celso P. Pesce
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Strain Curve ◽  
Element Model ◽  
Steel Tube ◽  
Gas Production ◽  
Three Dimensional Model ◽  
Steel Tubes ◽  
Umbilical Cable

Abstract Umbilical cables are fundamental equipment used in deep and ultra-deep waters oil and gas production systems. The complexity of this kind of structure leads structural analysis to be currently performed with numerical tools. This paper presents a nonlinear three-dimensional finite element model of a typical armored Steel Tube Umbilical Cable (STU) subjected to crushing loads imposed to the umbilical cable during laying operation. The study focuses on the analysis of the stress distribution in the steel tubes at caterpillar shoes, mainly at the entry/exit transition regions. With the use of a commercial software, the finite element model is constructed, considering geometric and materials nonlinearities. Crushing loads are imposed by two rigid plates. Focus is given on the duplex tubes, with the material stress-strain curve modeled from a specific crushing experiment with a single tube and by using a classic Ramberg-Osgood fitting. Firstly, comparisons at mid-length of the three-dimensional model are made with the results from a simpler and planar finite element model. Then, the localized three-dimensional effects are analyzed. The results show a considerable increase of the stress levels in the steel tubes at these transition regions, with the occurrence of stress field redistribution after the onset of plastic deformation.

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.

scholarly journals Three-dimensional finite element modeling for evaluation of laryngomalacia severity in infants and children

2020 ◽  
Vol 48 (6) ◽  
pp. 030006052092640
Author(s):  
Hongming Xu ◽  
Jiali Chen ◽  
Shilei Pu ◽  
Xiaoyan Li
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Three Dimensional ◽  
Element Model ◽  
3D Finite Element ◽  
Element Modeling ◽  
Laryngeal Cartilage ◽  
Computed Tomography Images

This study was performed to investigate the feasibility of using a three-dimensional (3D) finite element model for laryngomalacia severity assessment. We analyzed laryngeal computed tomography images of seven children with laryngomalacia using Mimics software. The gray threshold of different tissues was distinguishable, and a 3D visualization model and finite element model were constructed. The laryngeal structure parameters were defined. The peak von Mises stress (PVMS) value was obtained through laryngeal mechanical analysis. The PVMS values of the laryngeal soft tissue and cartilage scaffolds were independently correlated with disease severity. After stress loading the model, the relationship between laryngomalacia severity and the PVMS value was apparent. However, the PVMS value of laryngeal soft tissue was not correlated with laryngomalacia severity. This study established the efficacy of a finite element model to illustrate the morphological features of the laryngeal cavity in infants with laryngomalacia. However, further study is required before widespread application of 3D finite element modeling of laryngomalacia. PVMS values of the laryngeal cartilage scaffold might be useful for assessment of laryngomalacia severity. These findings support the notion that structural abnormalities of the laryngeal cartilage may manifest as quantifiable changes in stress variants of the supraglottic larynx.

scholarly journals Comparison of Hertzian and JKR theories with a finite element model in boundary lubrication conditions between a compression ring and a cylinder

2018 ◽  
Vol 188 ◽  
pp. 04009
Author(s):  
Kyriakos Grigoriadis ◽  
Anastasios Zavos ◽  
Pantelis G. Nikolakopoulos
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Combustion Engine ◽  
Three Dimensional ◽  
Element Model ◽  
Elastic Model ◽  
Three Dimensional Model ◽  
Dry Conditions ◽  
The Common ◽  
Lubrication Conditions

This study focuses on the creation of an isothermal elastic model to highlight, through stresses, the occurrence of plastic deformation in certain crank angles under extreme dry conditions inside an internal combustion engine. The stresses that are exported from this analysis are pointing out not only the necessity for an elastoplastic model to be created, but also the importance of predicting the correct friction coefficient, as pointed out by both the contact surface stress and those in depth of the two bodies in contact. A comparison between two coefficients of frictions and one frictionless case is conducted. The comparison between the finite element model and the adhesion mathematical model of Johnson, Kendall and Roberts (JKR), seals the importance of the interaction forces, acting on the common solid surface, in the pursuit of defining a propriate contact patch. Furthermore, a three-dimensional model is proposed for further investigation, highlighting the importance of modelling surface’s micro asperities for a solid stress analysis.

Biomechanical Structural Effect of Pinball Region Contact Applied to a Finite Element Model of Human Foot

2019 ◽  
Author(s):  
Agustín Vidal-Lesso ◽  
Carlos Lara-Velázquez ◽  
Javier Bayod-López ◽  
Ricardo Becerro de Bengoa Vallejo ◽  
Natali Mancera Campos
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Structural Effect ◽  
Contact Radius ◽  
Three Dimensional Model ◽  
Human Foot ◽  
Contact Parameters

Abstract Developing a finite element model of the human foot to analyze the numerical effect of the contact between its bones can also help to understand the complex biomechanics of this member. Therefore, in this work, a three-dimensional model of finite elements of the foot is developed, in order to determine the contact radius between each pair of bones, which help to achieve an adequate distribution of body weight and be able to perform a correct characterization of the biomechanical effect of the foot. In the finite element model developed in this work, the cartilage was replaced by the pair of contact between two bodies (bones) and was simplified to the bony and ligamentous system. It was observed that the radius of the contact sphere of the pinball region has a great impact on the distribution of reactions with the ground (GRF) and the general behavior of the simulation. By varying the contact parameters, it was possible to reduce the error of the results obtained by the simulation with respect to those obtained experimentally up to a value of less than 5%; emphasizing the importance of checking the contact parameters before continuing with a simulation of finite elements.

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