scholarly journals A Comparative Analysis of Standardised Threads for Use in Implants for Direct Skeletal Attachment of Limb Prosthesis: A Finite Element Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Piotr Prochor ◽  
Eugeniusz Sajewicz
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Comparative Analysis ◽  
Stress Distribution ◽  
Additional Stress ◽  
Element Analysis ◽  
Proposed Modification ◽  
Implant Loading ◽  
Stress Patterns ◽  
Limb Prosthesis

The aim of the research was to determine the optimal thread’s shape to be used in implants for direct skeletal attachment of limb prosthesis. In addition, by testing appropriate parameters’ modification of the suitable thread, an attempt was made to maximise its effectiveness. The analyses included three thread types described in the ISO standards: shallow, symmetrical, and asymmetrical. The obtained results suggest that shallow thread ensures the lowest equivalent and directional stress peaks generated in the bone as well as favourable stress patterns and profiles during implant loading in relation to symmetrical and asymmetrical threads. Moreover, shallow thread ensured the generation of single equivalent and directional stress peaks, while symmetrical and asymmetrical threads provided additional stress peak for equivalent as well as for each of directional peaks. Subsequently, optimisation of the shallow thread’s shape was conducted by changing two relevant thread’s parameters (flank angle and rounding arc) which influence the generated stress distribution. The highest reduction of stress peaks was obtained while reducing the rounding arc by 0.2 mm. Therefore, it can be stated that the proposed modification of the HA thread can lead to obtaining a higher biomechanical effectiveness of implants for direct skeletal attachment of limb prosthesis.

scholarly journals Comparative Analysis of Stress and Deformation between One-Fenced and Three-Fenced Dental Implants Using Finite Element Analysis

2021 ◽  
Vol 10 (17) ◽  
pp. 3986
Author(s):  
Chia-Hsuan Lee ◽  
Arvind Mukundan ◽  
Szu-Chien Chang ◽  
Yin-Lai Wang ◽  
Shu-Hao Lu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Comparative Analysis ◽  
Stress Distribution ◽  
Dental Implant ◽  
Maximum Stress ◽  
Vertical Force ◽  
Element Analysis ◽  
Different Types ◽  
Stress And Deformation

Finite element analysis (FEA) has always been an important tool in studying the influences of stress and deformation due to various loads on implants to the surrounding jaws. This study assessed the influence of two different types of dental implant model on stress dissipation in adjoining jaws and on the implant itself by utilizing FEA. This analysis aimed to examine the effects of increasing the number of fences along the implant and to compare the resulting stress distribution and deformation with surrounding bones. When a vertical force of 100 N was applied, the largest displacements found in the three-fenced and single-fenced models were 1.7469 and 2.5267, respectively, showing a drop of 30.8623%. The maximum stress found in the three-fenced and one-fenced models was 13.518 and 22.365 MPa, respectively, showing a drop of 39.557%. Moreover, when an oblique force at 35° was applied, a significant increase in deformation and stress was observed. However, the three-fenced model still had less stress and deformation compared with the single-fenced model. The FEA results suggested that as the number of fences increases, the stress dissipation increases, whereas deformation decreases considerably.

A NOVEL METHOD FOR THE DESIGN OF PROSTHESES BASED ON THERMOELASTIC STRESS ANALYSIS AND FINITE ELEMENT ANALYSIS

2014 ◽  
Vol 14 (05) ◽  
pp. 1450064
Author(s):  
FERDINANDO CANNELLA ◽  
ALBERTO GARINEI ◽  
MARIAPAOLA D'IMPERIO ◽  
GIANLUCA ROSSI
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Low Cost ◽  
Thermoelastic Stress ◽  
Fe Model ◽  
Element Analysis ◽  
The People ◽  
Teak Wood ◽  
Stress Patterns

This work is about a prosthesis destined for the people of Senegal and the victims of mines that have been spread throughout countries involved in war. The purpose of this study is to design a new, low-cost prosthesis using the materials produced in Senegal: teak wood and iron (AISI 304). In order to optimize the design of the new prosthesis, a methodology was developed to evaluate stress patterns for different configurations. A commercial CAD and ANSYS Workbench were used to define prosthesis geometry and to perform Finite Element Analysis. Load and constraints were defined according to Regulation ISO10328-2006, and stress distribution was estimated using the FE model. Fatigue due to the cycling load was also taken into account. The two materials currently used in western countries, titanium and steel (AISI 1020), were compared to iron and teak in order to determine the prosthesis' lifespan based on the differences in structural behaviors. An experimental, non-contact measurement technique based on the Thermoelastic principle is proposed here to validate the FE model. This technique permits the evaluation of superficial stress patterns on the prosthesis subjected to a cyclic load. A loading rig was built to test the prosthesis, and experimental and FEM results were compared to allow qualitative mechanical assessment of the new prosthesis. The finding of this work was that the prosthesis can indeed be built using autochthonous materials such as teak and iron. Moreover, the methodology proposed can be used for the performance prediction and design of new prostheses using materials that are typically expensive or difficult to test (such as wood), allowing for optimization of the geometry based on stress distribution, an increase in reliability and a decrease in costs.

scholarly journals Three-Dimensional Finite Element Analysis of Stress Distribution in a Tooth Restored with Full Coverage Machined Polymer Crown

2021 ◽  
Vol 11 (3) ◽  
pp. 1220
Author(s):  
Azeem Ul Yaqin Syed ◽  
Dinesh Rokaya ◽  
Shirin Shahrbaf ◽  
Nicolas Martin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Intraoral Scanner ◽  
Element Analysis ◽  
Dental Ceramic ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Ceramic Crown

The effect of a restored machined hybrid dental ceramic crown–tooth complex is not well understood. This study was conducted to determine the effect of the stress state of the machined hybrid dental ceramic crown using three-dimensional finite element analysis. Human premolars were prepared to receive full coverage crowns and restored with machined hybrid dental ceramic crowns using the resin cement. Then, the teeth were digitized using micro-computed tomography and the teeth were scanned with an optical intraoral scanner using an intraoral scanner. Three-dimensional digital models were generated using an interactive image processing software for the restored tooth complex. The generated models were imported into a finite element analysis software with all degrees of freedom concentrated on the outer surface of the root of the crown–tooth complex. To simulate average occlusal load subjected on a premolar a total load of 300 N was applied, 150 N at a buccal incline of the palatal cusp, and palatal incline of the buccal cusp. The von Mises stresses were calculated for the crown–tooth complex under simulated load application was determined. Three-dimensional finite element analysis showed that the stress distribution was more in the dentine and least in the cement. For the cement layer, the stresses were more concentrated on the buccal cusp tip. In dentine, stress was more on the cusp tips and coronal 1/3 of the root surface. The conventional crown preparation is a suitable option for machined polymer crowns with less stress distribution within the crown–tooth complex and can be a good aesthetic replacement in the posterior region. Enamic crowns are a good viable option in the posterior region.

scholarly journals A Machine Learning Approach as a Surrogate for a Finite Element Analysis: Status of Research and Application to One Dimensional Systems

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1654
Author(s):  
Poojitha Vurtur Badarinath ◽  
Maria Chierichetti ◽  
Fatemeh Davoudi Kakhki
Keyword(s):  
Machine Learning ◽  
Neural Networks ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Artificial Neural Networks ◽  
Stress Distribution ◽  
Maintenance Scheduling ◽  
Element Analysis ◽  
One Dimensional ◽  
Artificial Neural

Current maintenance intervals of mechanical systems are scheduled a priori based on the life of the system, resulting in expensive maintenance scheduling, and often undermining the safety of passengers. Going forward, the actual usage of a vehicle will be used to predict stresses in its structure, and therefore, to define a specific maintenance scheduling. Machine learning (ML) algorithms can be used to map a reduced set of data coming from real-time measurements of a structure into a detailed/high-fidelity finite element analysis (FEA) model of the same system. As a result, the FEA-based ML approach will directly estimate the stress distribution over the entire system during operations, thus improving the ability to define ad-hoc, safe, and efficient maintenance procedures. The paper initially presents a review of the current state-of-the-art of ML methods applied to finite elements. A surrogate finite element approach based on ML algorithms is also proposed to estimate the time-varying response of a one-dimensional beam. Several ML regression models, such as decision trees and artificial neural networks, have been developed, and their performance is compared for direct estimation of the stress distribution over a beam structure. The surrogate finite element models based on ML algorithms are able to estimate the response of the beam accurately, with artificial neural networks providing more accurate results.

scholarly journals Folding photopolymerized origami sheets by post-curing

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Xiaodong He ◽  
Christopher-Denny Matte ◽  
Tsz-Ho Kwok
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Principal Stress ◽  
Second Step ◽  
Post Processing ◽  
Element Analysis ◽  
Digital Light Processing ◽  
Processing Step ◽  
Lower Maximum

AbstractThe paper presents a novel manufacturing approach to fabricate origami based on 3D printing utilizing digital light processing. Specifically, we propose to leave part of the model uncured during the printing step, and then cure it in the post-processing step to set the shape in a folded configuration. While the cured regions in the first step try to regain their unfolded shape, the regions cured in the second step attempt to keep their folded shape. As a result, the final shape is obtained when both regions’ stresses reach equilibrium. Finite element analysis is performed in ANSYS to obtain the stress distribution on common hinge designs, demonstrating that the square-hinge has a lower maximum principal stress than elliptical and triangle hinges. Based on the square-hinge and rectangular cavity, two variables—the hinge width and the cavity height—are selected as principal variables to construct an empirical model with the final folding angle. In the end, experimental verification shows that the developed method is valid and reliable to realize the proposed deformation and 3D development of 2D hinges.

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