scholarly journals A Finite Element Analysis of the Fatigue Behavior and Risk of Failure of Immediate Provisional Implants

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 535
Author(s):  
María Prados-Privado ◽  
Carlos Ivorra ◽  
Carlos Martínez-Martínez ◽  
Sergio Alexandre Gehrke ◽  
José Luis Calvo-Guirado ◽  
...  
Keyword(s):  
Finite Element ◽  
Dental Implants ◽  
Fatigue Behavior ◽  
Maximum Load ◽  
Probability Of Failure ◽  
Fracture Load ◽  
Element Analysis ◽  
Compression Load ◽  
Maximum Value ◽  
Number Of Cycles

Background: Temporary dental implants are used to support provisional prostheses. The goal of this study was to obtain the stress–number (S–N) curves of cycles of five temporary dental implants employing finite element methods. Additionally, a probabilistic analysis was carried out to obtain the failure probability of each dental implant. Methods: To obtain these curves, first the maximum value of the fracture load was obtained by simulation of a compression test. Subsequently, the fatigue life was simulated by varying each of the loads from the maximum value to a minimum value (10% of the maximum value), and the minimum number of cycles that it should support was calculated. Results: The fatigue limit of titanium in these implants was around 200 MPa with the maximum number of cycles between 64,976 and 256,830. The maximum compression load was between 100 and 80 N. Regarding the probability of failure, all implants were expected to behave similarly. Conclusions: This study of finite elements provided the values of maximum load supported by each of the implants, and the relationship between the stress in the implant and the number of cycles that it could support with a probability of failure. An international standard on how to perform fatigue studies in temporary dental implants was deemed necessary.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

scholarly journals Mechanical analysis of prosthetic bars and dental implants in 3 and 4 implant-supported overdenture protocols using finite element analysis

2021 ◽  
Author(s):  
Luiz Bassi Junior ◽  
Rafael Oliveira de Souza Silva ◽  
Victor Hugo Dias dos Santos ◽  
Abner da Rocha Lourenço ◽  
Paulo Vinicius Trevizoli ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dental Implants ◽  
Mechanical Analysis ◽  
Element Analysis

Finite Element Analysis of the ESTELA M1 Airplane Firewall (Representative Specimen)

2011 ◽  
Author(s):  
V. Ramirez-Elias ◽  
E. Ledesma-Orozco ◽  
H. Hernandez-Moreno
Keyword(s):  
Finite Element ◽  
Federal Aviation Administration ◽  
Element Model ◽  
Maximum Load ◽  
Load Factor ◽  
Representative Specimen ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Element Simulation ◽  
The Relationship

This paper shows the finite element simulation of a representative specimen from the firewall section in the AEROMARMI ESTELA M1 aircraft. This specimen is manufactured in glass and carbon / epoxy laminates. The specimen is subjected to a load which direction and magnitude are determined by a previous dynamic loads study [10], taking into account the maximum load factor allowed by the FAA (Federal Aviation Administration) for utilitarian aircrafts [11]. A representative specimen is manufactured with the same features of the firewall. Meanwhile a fix is built in order to introduce the load directions on the representative specimen. The relationship between load and displacement is plotted for this representative specimen, whence the maximum displacement at the specific load is obtained, afterwards it is compared with the finite element model, which is modified in its laminate thicknesses in order to decrease the deviation error; subsequently this features could be applied to perform the whole firewall analysis in a future model [10].

scholarly journals Experimental and Numerical Crack Initiation Analysis of the Compressor Blades Working in Resonance Conditions

2011 ◽  
Vol 2011 (3) ◽  
pp. 134-153
Author(s):  
Lucjan Witek
Keyword(s):  
Finite Element ◽  
Crack Initiation ◽  
Transverse Vibration ◽  
Numerical Models ◽  
Fatigue Behavior ◽  
Time History ◽  
Fatigue Properties ◽  
Compressor Blades ◽  
Blade Vibration ◽  
Number Of Cycles

Experimental and Numerical Crack Initiation Analysis of the Compressor Blades Working in Resonance ConditionsThis paper presents the results of a complex experimental and numerical crack initiation analysis of the helicopter turbo-engine compressor blades subjected to vibrations. A nonlinear finite element method was utilized to determine the stress state of the blade during the first mode of transverse vibration. In this analysis, the numerical models without defects as well as those with V-notches were defined. The quality of the numerical solution was checked by the convergence analysis. The obtained results were next used as an input data into crack initiation (ε-N) analyses performed for the load time history equivalent to one cycle of the transverse vibration. In the fatigue analysis, the different methods such as: Neuber elastic-plastic strain correction, linear damage summation and Palmgreen-Miner rule were utilized. As a result of ε-N analysis, the number of load cycles to the first fatigue crack appearing in the compressor blades was obtained. Moreover, the influence of the blade vibration amplitude on the number of cycles to the crack initiation was analyzed. Values of the fatigue properties of the blade material were calculated using the Baumel-Seeger and Muralidharan methods. The influence of both the notch radius and values of the UTS of the blade material on the fatigue behavior of the structure was also considered. In the last part of the work, the finite element results were compared with the results of experimental vibration HCF tests performed for the compressor blades.

scholarly journals Valuation of stress patterns in the peri implant bone of non-parallel implants supporting a long-cantilevered prosthesis: a 3D finite element analysis

2020 ◽  
pp. 18-24
Author(s):  
Mohammed Abusaad Siddiqui ◽  
Sudheer N ◽  
Dulala Vikram Raj ◽  
Aditi Chintamani Sabnis ◽  
Alluru Amrutesh ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dental Implants ◽  
Three Dimensional ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Fixed Prosthesis ◽  
Edentulous Patients ◽  
Area Of Concern ◽  
Three Dimensional Finite Element

The treatment modality for completely edentulous arches has shifted from complete dentures to dental implants during the last 15-20 years. Tilting of implants has reduced the concern of resorbed posterior ridges in completely edentulous patients with “All-on-four” and “All-on-six” concept of dental implants. The purpose of this study is to compare the biomechanical behaviour of the “All-on-four”, “All-on-six” models with tilted distal implants at different angulations of 30 and 45 ° with four parallel placed implant-supported fixed prosthesis, and six parallel placed implant-supported fixed prosthesis models as controls using three-dimensional finite element analysis. The results showed that in all the models, in cancellous bone, cortical bone, implant and prosthesis – “All-on-four” model with distal implants tilted at an angulation of 30° showed stress values less than or equivalent to all the other models except on the implant in the presence of cantilever and on prosthesis during full mouth biting load where maximum stresses were observed. The study shows that All-on-four concept with tilted distal implants at an angulation of 30° showed stress values favourable for the rehabilitation of completely edentulous maxilla, but the presence of cantilever remains an area of concern.

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