Página 1 dos resultados de 5937 itens digitais encontrados em 0.055 segundos

Avaliação das distribuições de tensões, por meio da análise de elementos finitos, em uma hemi-maxila, durante a fase de retração anterior por deslizamento, na mecânica ortodôntica; Evaluation of the tensions distributions, using the finite element analysis, in an hemi-maxilla during a sliding anterior retraction , in an orthodontic mechanics

Lopes, Luiz Vicente de Moura
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 15/04/2011 PT
Relevância na Pesquisa
95.89%
O objetivo deste estudo foi analisar, por meio do método dos elementos finitos, como ocorreram as distribuições de tensões nos dentes, osso e aparelho ortodôntico, durante a fase de retração por deslizamento (150g), em um caso com extrações. Simularam-se duas posições do gancho (mesial e distal de canino), duas alturas do gancho (4 e 9mm) e duas alturas posteriores (gancho do tubo do molar e no miniimplante, a 9mm do arco). A amostra consistiu do corte axial da TCFC, de uma mulher de 17 anos de idade, com dentes bem nivelados. Foi desenvolvido um modelo 3D, da geometria da hemi-maxila direita e um modelo numérico, para obter os regimes de tensões e deformações gerados em um sistema de movimentação ortodôntica, por meio do software ANSYS® versão 12.0. Os sólidos dos braquetes e do fio ortodôntico foram incluídos a partir das dimensões fornecidas pelo fabricante. A montagem de todos os componentes foi feita por meio do SolidWorks 2009 SP4.1. A partir do cálculo das respostas do modelo, às cargas a que foi submetido, verificou-se que, os dentes que sofreram maiores concentrações de tensões foram os justapostos aos ganchos, sendo mais intensas as do gancho mesial, particularmente nos incisivos laterais. Embora...

Reabsorção radicular inflamatória induzida ortodonticamente: revisão sistemática e análise por elementos finitos; Orthodontically induced inflamatory root resorption: systematic review and finite element analysis

Roscoe, Marina Guimarães
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 29/05/2015 PT
Relevância na Pesquisa
95.9%
Capítulo 1. Objetivo: Acessar a literatura científica para determinar o nível de evidência científica que suporta a associação da reabsorção radicular inflamatória induzida ortodonticamente (RRIIO) com diferentes sistemas de força ortodôntica. Material e Método: A busca sistemática computadorizada foi realizada nas bases de dados PubMed, Cochrane e Embase, sem restrições quanto ao ano, status ou idioma de publicação. Os critérios de seleção incluíram estudos conduzidos em no mínimo 10 pacientes submetidos ao tratamento ortodôntico com aparelhos fixos ou termoplásticos removíveis, e que apresentaram descrição do sistema de forças utilizado. Resultados: A busca eletrônica inicial das bases de dados identificou 259 artigos. Após o processo de revisão, 21 artigos preencheram os critérios de inclusão. O tamanho da amostra variou entre 10 e 73 pacientes. A maioria dos artigos foi classificada como alto nível de evidência científica e baixo risco de viés. Conclusões: A análise da literatura disponível revelou que parece existir correlação positiva entre o aumento dos níveis de força e o aumento da reabsorção radicular, bem como entre o aumento do tempo de tratamento e o aumento da reabsorção radicular. Além disso...

Otimização de forma estrutural e aerodinâmica usando análise IsoGeométrica e Elementos Finitos; Structural and aerodynamic shape optimization using isogeometric and finite element analysis

Espath, Luis Felipe da Rosa
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
POR
Relevância na Pesquisa
95.93%
Neste trabalho buscou-se consolidar aspectos referentes à otimização de problemas envolvidos na mecânica dos meios contínuos, envolvendo diferentes áreas do conhecimento, tais como: otimização matemática, diferenciação automática, análise estrutural, análise aerodinâmica, parametrização de curvas, superfícies e sólidos do tipo B-spline racionais não-uniformes (NURBS, acrônimo do inglês), análise IsoGeométrica (IGA, acrônimo do inglês) e análise por Elementos Finitos (FEA, acrônimo do inglês). Como objetivo final busca-se otimizar formas de cascas estruturais e formas de corpos aerodinâmicos imersos em escoamentos compressíveis. No que concerne à análise estrutural, esta é realizada via análise IsoGeométrica utilizando elementos sólidos para modelar cascas. Uma cinemática co-rotacional abrangente e precisa baseada na exata decomposição polar é desenvolvida, para lidar com problemas estáticos e dinâmicos altamente não lineares. Na análise estática foram implementados o método de Newton-Raphson e controle de deslocamentos generalizado, para problemas dinâmicos foram implementados o método -generalizado (G ) e o método energia momento generalizado (GEMM+ ). A análise aerodinâmica é realizada via análise por Elementos Finitos para modelar escoamentos compressíveis viscosos e não viscosos em regimes transônicos e supersônicos. Um esquema característico baseado na separação da equação de momento (CBS...

Effect of Passive Fit Absence in the Prosthesis/Implant/Retaining Screw System: A Two-Dimensional Finite Element Analysis

Gomes, Erica Alves; Assuncao, Wirley Goncalves; Tabata, Lucas Fernando; Ricardo Barao, Valentim Adelino; Delben, Juliana Aparecida; Sousa, Edson Antonio Capello
Fonte: Lippincott Williams & Wilkins Publicador: Lippincott Williams & Wilkins
Tipo: Artigo de Revista Científica Formato: 2000-2005
ENG
Relevância na Pesquisa
95.89%
The misfit between prostheses and implants is a clinical reality, but the level that can be accepted without causing mechanical or biologic problem is not well defined. This study investigates the effect of different levels of unilateral angular misfit prostheses in the prosthesis/implant/retaining screw system and in the surrounding bone using finite element analysis. Four models of a two-dimensional finite element were constructed: group I (control), prosthesis that fit the implant; groups 2 to 4, prostheses with unilateral angular misfit of 50, 100, and 200 mu m, respectively. A load of 133 N was applied with a 30-degree angulation and off-axis at 2 mm from the long axis of the implant at the opposite direction of misfit on the models. Taking into account the increase of the angular misfit, the stress maps showed a gradual increase of prosthesis stress and uniform stress in the implant and trabecular bone. Concerning the displacement, an inclination of the system due to loading and misfit was observed. The decrease of the unilateral contact between prosthesis and implant leads to the displacement of the entire system, and distribution and magnitude alterations of the stress also occurred.

Platform Switching: Biomechanical Evaluation Using Three-Dimensional Finite Element Analysis

Tabata, Lucas Fernando; Rocha, Eduardo Passos; Ricardo Barao, Valentim Adelino; Assuncao, Wirley Goncalves
Fonte: Quintessence Publishing Co Inc Publicador: Quintessence Publishing Co Inc
Tipo: Artigo de Revista Científica Formato: 482-491
ENG
Relevância na Pesquisa
95.89%
Purpose: The objective of this study was to evaluate, using three-dimensional finite element analysis (3D FEA), the stress distribution in peri-implant bone tissue, implants, and prosthetic components of implant-supported single crowns with the use of the platform-switching concept. Materials and Methods: Three 3D finite element models were created to replicate an external-hexagonal implant system with peri-implant bone tissue in which three different implant-abutment configurations were represented. In the regular platform (RP) group, a regular 4.1-mm-diameter abutment (UCLA) was connected to regular 4.1-mm-diameter implant. The platform-switching (PS) group was simulated by the connection of a wide implant (5.0 mm diameter) to a regular 4.1-mm-diameter UCLA abutment. In the wide-platform (WP) group, a 5.0-mm-diameter UCLA abutment was connected to a 5.0-mm-diameter implant. An occlusal load of 100 N was applied either axially or obliquely on the models using ANSYS software. Results: Both the increase in implant diameter and the use of platform switching played roles in stress reduction. The PS group presented lower stress values than the RP and WP groups for bone and implant. In the peri-implant area, cortical bone exhibited a higher stress concentration than the trabecular bone in all models and both loading situations. Under oblique loading...

Effect of Metal-Ceramic or All-Ceramic Superstructure Materials on Stress Distribution in a Single Implant-Supported Prosthesis: Three-Dimensional Finite Element Analysis

Gomes, Erica Alves; Ricardo Barao, Valentim Adelino; Rocha, Eduardo Passos; de Almeida, Erika Oliveira; Assuncao, Wirley Goncalves
Fonte: Quintessence Publishing Co Inc Publicador: Quintessence Publishing Co Inc
Tipo: Artigo de Revista Científica Formato: 1202-1209
ENG
Relevância na Pesquisa
95.92%
Purpose: This three-dimensional finite element analysis study evaluated the effect of different material combinations on stress distribution within metal-ceramic and all-ceramic single implant-supported prostheses. Materials and Methods: Three-dimensional finite element models reproducing a segment of the maxilla with a missing left first premolar were created. Five groups were established to represent different superstructure materials: GP, porcelain fused to gold alloy; GR, modified composite resin fused to gold alloy; TP, porcelain fused to titanium; TR, modified composite resin fused to titanium; and ZP, porcelain fused to zirconia. A 100-N vertical force was applied to the contact points of the crowns. All models were fixed in the superior region of bone tissue and in the mesial and distal faces of the maxilla section. Stress maps were generated by processing with finite element software. Results: Stress distribution and stress values of supporting bone were similar for the GP, GR, TP, and ZP models (1,574.3 MPa, 1,574.3 MPa, 1,574.3 MPa, and 1,574.2 MPa, respectively) and different for the TR model (1,838.3 MPa). The ZP model transferred less stress to the retention screw (785 MPa) than the other groups (939 MPa for GP, 961 MPa for GR...

Implant Platform Switching: Biomechanical Approach Using Two-Dimensional Finite Element Analysis

Tabata, Lucas Fernando; Assuncao, Wirley Goncalves; Ricardo Barao, Valentim Adelino; Sousa, Edson Antonio Capello; Gomes, Erica Alves; Delben, Juliana Aparecida
Fonte: Lippincott Williams & Wilkins Publicador: Lippincott Williams & Wilkins
Tipo: Artigo de Revista Científica Formato: 182-187
ENG
Relevância na Pesquisa
95.89%
In implant therapy, a peri-implant bone resorption has been noticed mainly in the first year after prosthesis insertion. This bone remodeling can sometimes jeopardize the outcome of the treatment, especially in areas in which short implants are used and also in aesthetic cases. To avoid this occurrence, the use of platform switching (PS) has been used. This study aimed to evaluate the biomechanical concept of PS with relation to stress distribution using two-dimensional finite element analysis. A regular matching diameter connection of abutment-implant (regular platform group [RPG]) and a PS connection (PS group [PSG]) were simulated by 2 two-dimensional finite element models that reproduced a 2-piece implant system with peri-implant bone tissue. A regular implant (prosthetic platform of 4.1 mm) and a wide implant (prosthetic platform of 5.0 mm) were used to represent the RPG and PSG, respectively, in which a regular prosthetic component of 4.1 mm was connected to represent the crown. A load of 100 N was applied on the models using ANSYS software. The RPG spreads the stress over a wider area in the peri-implant bone tissue (159 MPa) and the implant (1610 MPa), whereas the PSG seems to diminish the stress distribution on bone tissue (34 MPa) and implant (649 MPa). Within the limitation of the study...

Effect of Superstructure Materials and Misfit on Stress Distribution in a Single Implant-Supported Prosthesis: A Finite Element Analysis

Assuncao, Wirley Goncalves; Gomes, Erica Alves; Ricardo Barao, Valentim Adelino; Delben, Juliana Aparecida; Tabata, Lucas Fernando; Sousa, Edson Antonio Capello
Fonte: Lippincott Williams & Wilkins Publicador: Lippincott Williams & Wilkins
Tipo: Artigo de Revista Científica Formato: 689-695
ENG
Relevância na Pesquisa
95.9%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 07/55073-1; This finite element analysis study evaluated the optimal material combination for the superstructure of single implant-supported prosthesis with different fit patterns. Two models of a two-dimensional finite element analysis were constructed: group A (control), prosthesis presenting precise fit to implant; and group B, prostheses with unilateral angular misfit of 100 Km. Each group was divided into 5 subgroups according to different materials for framework (gold alloy, titanium, and zirconia) and veneering (porcelain and modified composite resin). Evaluation was performed on ANSYS software with 133-N load applied at the opposite side of misfit on the model. The load was applied with a 30-degree angulation and 2-mm off-axis. The presence of unilateral angular misfit (group B) increased the von Mises stresses in the implant (40%) and retention screw (7%) in comparison to group A. The combination of porcelain/titanium and porcelain/zirconia displayed more favorable stress distribution. When gold alloy was used as a framework material, there was no difference in stress values for both veneering materials in all groups. The use of stiffer and softer superstructures materials did not affect the stress distribution and stress values in the supporting tissue. According to the biomechanical point of view...

Periodontal ligament influence on the stress distribution in a removable partial denture supported by implant: a finite element analysis

Archangelo, Carlos Marcelo; Rocha, Eduardo Passos; Pereira, Joao Antonio; Martin Junior, Manoel; Anchieta, Rodolfo Bruniera; Freitas Junior, Amilcar Chagas
Fonte: Universidade de São Paulo (USP), Faculdade de Odontologia de Bauru Publicador: Universidade de São Paulo (USP), Faculdade de Odontologia de Bauru
Tipo: Artigo de Revista Científica Formato: 362-368
ENG
Relevância na Pesquisa
95.89%
Objective: The non-homogenous aspect of periodontal ligament (PDL) has been examined using finite element analysis (FEA) to better simulate PDL behavior. The aim of this study was to assess, by 2-D FEA, the influence of non-homogenous PDL on the stress distribution when the free-end saddle removable partial denture (RPD) is partially supported by an osseointegrated implant. Material and Methods: Six finite element (FE) models of a partially edentulous mandible were created to represent two types of PDL (non-homogenous and homogenous) and two types of RPD (conventional RPD, supported by tooth and fibromucosa; and modified RPD, supported by tooth and implant [10.00x3.75 mm]). Two additional FE models without RPD were used as control models. The non-homogenous PDL was modeled using beam elements to simulate the crest, horizontal, oblique and apical fibers. The load (50 N) was applied in each cusp simultaneously. Regarding boundary conditions the border of alveolar ridge was fixed along the x axis. The FE software (Ansys 10.0) was used to compute the stress fields, and the von Mises stress criterion (sigma vM) was applied to analyze the results. Results: The peak of sigma vM in non-homogenous PDL was higher than that for the homogenous condition. The benefits of implants were enhanced for the non-homogenous PDL condition...

Biomechanical Evaluation of Platform Switching in Different Implant Protocols: Computed Tomography-Based Three-Dimensional Finite Element Analysis

Pessoa, Roberto S.; Vaz, Luis Geraldo; Marcantonio, Elcio; Vander Sloten, Jos; Duyck, Joke; Jaecques, Siegfried V. N.
Fonte: Quintessence Publishing Co Inc Publicador: Quintessence Publishing Co Inc
Tipo: Artigo de Revista Científica Formato: 911-919
ENG
Relevância na Pesquisa
95.9%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 06/06844-2; Purpose: To evaluate the influence of platform switching on the biomechanical environment of implants in different placement and loading protocols. Materials and Methods: A computed tomography-based finite element model of a maxillary central incisor extraction socket was constructed containing a conical 13-mm external-hex implant with a 4.3-mm-diameter shoulder. Abutment models that were 4.3 mm and 3.8 mm in diameter were then imported and aligned to the implant. The 4.3-mm abutment edge matched perfectly the edge of the implant shoulder, while the 3.8-mm abutment assumed a platform-switching configuration. Then, immediately placed, immediately loaded, and osseointegrated (ie, conventional delayed loaded) protocols were simulated. Analysis of variance was used to interpret the data for peak equivalent strain (EQV strain) in the bone, bone-to-implant relative displacement, peak von Mises stress (EQV stress) in the abutment screw, and implant-abutment gap. Results: In the same clinical situation...

Stress distribution in ceramic restorations over natural tooth using finite element analysis. lithium disilicate x aluminum oxide material

Freitas Jr., Amilcar Chagas; Rocha, Eduardo Passos; dos Santos, Paulo Henrique; de Almeida, Erika Oliveira; de Anchieta, Rodolfo Bruniera; Martín Jr., Manoel; Archangelo, Carlos Marcelo
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 43-55
ENG
Relevância na Pesquisa
95.89%
Background: Data on stress distribution in tooth-restoration interface with different ceramic restorative materials are limited. The aim of this chapter was to assess the stress distribution in the interface of ceramic restorations with laminate veneer or full-coverage crown with two different materials (lithium dissilicate and densely sintered aluminum oxide) under different loading areas through finite element analysis. Materials and Methods: Six two-dimensional finite element models were fabricated with different restorations on natural tooth: laminate veneer (IPS Empress, IPS Empress Esthetic and Procera AllCeram) or full-coverage crown (IPS e.max Press and Procera AllCeram). Two different loading areas (L) (50N) were also determined: palatal surface at 45° in relation to the long axis of tooth (L1) and perpendicular to the incisal edge (L2). A model with higid natural tooth was used as control. von Mises equivalent stress (σ vM) and maximum principal stress (σ max) were obtained on Ansys software. Results: The presence of ceramic restoration increased σ vM and σ max in the adhesive interface, mainly for the aluminum oxide (Procera AllCeram system) restorations. The full-coverage crowns generated higher stress in the adhesive interface under L1 while the same result was observed for the laminate veneers under L2. Conclusions: Lithium dissilicate and densely sintered aluminum oxide restorations exhibit different behavior due to different mechanical properties and loading conditions. © 2011 Nova Science Publishers...

Influence of buccal cusp reduction when using porcelain laminate veneers in premolars. A comparative study using 3-D finite element analysis

Archangelo, Carlos Marcelo; Rocha, Eduardo Passos; Anchieta, Rodolfo Bruniera; Martin, Manoel; Freitas, Amilcar Chagas; Ko, Ching-Chang; Cattaneo, Paolo M.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 221-227
ENG
Relevância na Pesquisa
95.98%
Objectives: Based on a maxillary premolar restored with laminate veneer and using the 3-D finite element analysis (FEA) and mCT data, the aim of this study was to evaluate the influence of different types of buccal cusp reduction on the stress distribution in the porcelain laminate veneer and in the resin luting cement layer. Methods: Two 3-D FEA models (M) of a maxillary premolar were built from mCT data. The buccal cusp reduction followed two configurations: Mt-buccal cusp completely covered by porcelain laminate veneer; and Mp-buccal cusp partially covered by porcelain laminate veneer. The loading (150 N in 458) was performed on the top of the buccal cusp. The finite element software (Ansys Workbench 10.0) was used to obtain the maximum shear stress (σmax) and maximum principal stress (σmax). Results: The Mp showed reduced the stress (σmax) in porcelain laminate veneer (from-2.3 to 24.5 MPa) in comparison with Mt (from-5.3 to 27.4 MPa). The difference between the peak and lower stress values of σmax in Mp (-6.8 to 26.7 MPa) and Mt (-5.3 to 27.4 MPa) was similar for the resin luting cement layer. The structures not exceeded the ultimate tensile strength or the shear bond strength. Conclusions: Cusp reduction did not affect significant increase in σmax and τmax. The Mt showed better stress distribution (τmax) than Mp. © 2011 Published by Elsevier Ireland on behalf of Japan Prosthodontic Society.

Finite element analysis of the simulated mechanical stresses in molar occlusion in the pterygoid pillar of a human skull = : Análise de elementos finitos das tensões mecânicas simuladas em oclusão molar no pilar pterigoideo de um crânio humano; Análise de elementos finitos das tensões mecânicas simuladas em oclusão molar no pilar pterigoideo de um crânio humano

Elisa Camila Santos Rolfini
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 09/12/2014 PT
Relevância na Pesquisa
95.94%
O esqueleto facial é formado por uma estrutura ideal para resistir às forças mastigatórias. O pilar pterigoideo suporta as tensões provenientes da mastigação posterior. O objetivo deste estudo foi avaliar a distribuição das tensões mecânicas simuladas no pilar pterigoideo, baseado em sua geometria, por meio da análise de elementos finitos. Foi selecionada uma tomografia computadorizada de um crânio humano seco do Laboratório de Elementos Finitos, Departamento de Morfologia, Área Anatomia, FOP / UNICAMP. No laboratório de Elementos Finitos foi utilizado o software InVesalius 3.0 (Brasil) para a realização da segmentação das imagens da tomografia computadorizada e, assim, selecionou-se o conjunto de imagens referentes à estrutura óssea e aos dentes de interesse na análise. As estruturas segmentadas foram reconstruídas tridimensionalmente e exportadas em formato estereolitográfico (STL). Este arquivo foi importado para o software Rhinoceros 5.0 (McNeil, Assoc USA), no qual foi realizada a modelagem Bio-CAD para obtenção da geometria. O modelo geométrico (CAD) obtido foi importado ao software ANSYS v14 (USA) para realização da análise de elementos finitos. Neste software, como configuração da análise foram aplicadas as seguintes condições: simetria na superfície de corte do plano sagital mediano...

Periodontal ligament influence on the stress distribution in a removable partial denture supported by implant: a finite element analysis

Archangelo,Carlos Marcelo; Rocha,Eduardo Passos; Pereira,João Antônio; Martin Junior,Manoel; Anchieta,Rodolfo Bruniera; Freitas Júnior,Amilcar Chagas
Fonte: Faculdade De Odontologia De Bauru - USP Publicador: Faculdade De Odontologia De Bauru - USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 EN
Relevância na Pesquisa
95.89%
OBJECTIVES: The non-homogenous aspect of periodontal ligament (PDL) has been examined using finite element analysis (FEA) to better simulate PDL behavior. The aim of this study was to assess, by 2-D FEA, the influence of non-homogenous PDL on the stress distribution when the free-end saddle removable partial denture (RPD) is partially supported by an osseointegrated implant. MATERIAL AND METHODS: Six finite element (FE) models of a partially edentulous mandible were created to represent two types of PDL (non-homogenous and homogenous) and two types of RPD (conventional RPD, supported by tooth and fibromucosa; and modified RPD, supported by tooth and implant [10.00x3.75 mm]). Two additional Fe models without RPD were used as control models. The non-homogenous PDL was modeled using beam elements to simulate the crest, horizontal, oblique and apical fibers. The load (50 N) was applied in each cusp simultaneously. Regarding boundary conditions the border of alveolar ridge was fixed along the x axis. The FE software (Ansys 10.0) was used to compute the stress fields, and the von Mises stress criterion (svM) was applied to analyze the results. RESULTS: The peak of svM in non-homogenous PDL was higher than that for the homogenous condition. The benefits of implants were enhanced for the non-homogenous PDL condition...

Computer graphics applied to anatomy: a study of two bio-cad modeling methods on finite element analysis of human edentulous hemi-mandible

Rossi, Ana Claudia; Freire, Alexandre Rodrigues; Botacin, Paulo Roberto; Ferreira Caria, Paulo Henrique; Prado, Felippe Bevilacqua
Fonte: Soc Chilena Anatomia Publicador: Soc Chilena Anatomia
Tipo: Artigo de Revista Científica Formato: 803-811
ENG
Relevância na Pesquisa
96%
Modeling is a step to perform a finite element analysis. Different methods of model construction are reported in literature, as the Bio-CAD modeling. The purpose of this study was to perform a model evaluation and application using two methods of Bio-CAD modeling from human edentulous hemi-mandible on the finite element analysis. From CT scans of dried human skull was reconstructed a stereolithographic model. Two methods of modeling were performed: STL conversion approach (Model 1) associated to STL simplification and reverse engineering approach (Model 2). For finite element analysis was used the action of lateral pterygoid muscle as loading condition to assess total displacement (D), equivalent von-Mises stress (VM) and maximum principal stress (MP). Two models presented differences on the geometry regarding surface number (1834 (model 1); 282 (model 2)). Were observed differences in finite element mesh regarding element number (30428 nodes/16683 elements (model 1); 15801 nodes/8410 elements (model 2). D, VM and MP stress areas presented similar distribution in two models. The values were different regarding maximum and minimum values of D (ranging 0-0.511 mm (model 1) and 0-0.544 mm (model 2), VM stress (6.36E-04-11.4 MPa (model 1) and 2.15E-04-14.7 MPa (model 2) and MP stress (-1.43-9.14 MPa (model 1) and -1.2-11.6 MPa (model 2). From two methods of Bio-CAD modeling...

Linear and non-linear finite element analysis of shear-corrected composites box beams

Vanegas,J.D.; Patiño,I.D.
Fonte: Associação Brasileira de Ciências Mecânicas Publicador: Associação Brasileira de Ciências Mecânicas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2013 EN
Relevância na Pesquisa
95.9%
The Updated Lagrangian formulation for non-linear finite element analysis is applied to the problem of thin-walled composites box beams undergoing large displacements. A shear correction factor for thin-closed rectangular sections is introduced into some terms of the variational formulation and its influence in the results is analyzed, in both linear and non-linear problems. The Vlasov's theory describing the coupled flexural-torsional phenomenon and the implementation of the FSDT theory in thin-walled beams is discussed, as well as the strains, stress resultants and constitutive relationships for composites box beams. The application of the Mechanic of Laminated Beam theory (MLB) to the calculation of the shear correction factors considering more constitutive terms for computing the shear flow in flanges and webs than those ones used in the original theory is also debated. The Updated Lagrangian finite element model applied in this work for non-linear analysis of box beams is described. A comparison of the numerical results with those obtained experimentally, analytically and by the numerical models proposed by other authors is done for both linear and non-linear problems. The assumptions made in this work and the formulation developed only applies to thin-walled beams that undergo large displacements...

Finite Element Analysis of Subsurface Damage of Ceramic Protheses in Simulated Intraoral Dental Resurfacing

Song, Xiao-Fei; Yin, Ling; Han, Yi-Gang; Li, Jia
Fonte: John Wiley & Sons Inc Publicador: John Wiley & Sons Inc
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
95.94%
Finite element analysis (FEA) was used to investigate the stress fields and the degrees of subsurface damage of ceramic prostheses in simulated intraoral dental resurfacing operations using clinical diamond burs. A two-dimensional finite element model was

Finite element analysis and optimization of composite wheelchair wheels

Kalyanasundaram, Shankar; Lowe, Adrian; Watters, Aaron
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
95.94%
A methodology for the design of Paralympics wheelchair wheels has been developed and provided a framework for comparison between design solutions. Finite element analysis was used as a tool to develop an understanding of wheel design, provide a basis for

Investigation of tetrahedron elements using automatic meshing in finite element analysis

Tseng, Gordon Bae-Ji
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
95.94%
This investigation examines the quality of finite element analysis (FEA) results based on the use of tetrahedron elements. For some classes of problems analyzed by the finite element method (FEM), the use of various polynomial order tetrahedra is considered quite acceptable. However, in other classes of problems, particularly stress analysis, users have a strong bias against these types of elements. Various case studies are performed, comparing results based on several types of three-dimensional elements.

Investigation of stress in an earthmover bucket using finite element analysis: A generic model for draglines

Gölbaşi,O; Demirel,N.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2015 EN
Relevância na Pesquisa
95.92%
Draglines are massive machines extensively utilized in opencast mines for overburden stripping. The demanding working environment induces fractures, wear and tear, and fatigue failures in dragline components and eventuates in extended maintenance, lengthy downtimes, and loss of production. The bucket is the main source of external loads on the machinery, since interactions with ground materials take place in this region. This study aims to develop a generic finite element model of the stress on an operating bucket. This entails (i) three-dimensional modelling of a dragline bucket, (ii) analytical estimation of resistive forces in the bucket movement, (iii) three-dimensional simulation of the moving bucket using finite element analysis (FEA), and (iv) sensitivity analysis to examine the effect of formation characteristics on stress variation. Simulation results imply that the drag hitch and digging teeth are the elements of the bucket that are most prone to failure. In addition, sensitivity analysis indicates that internal friction angle of the formation is the dominant parameter leading fluctuations in stress values. Changes in stress level are least influenced by formation density.