Análise dinâmica em vigas compostas com amortecimento utilizando o método dos elementos espectrais e elementos finitos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Implantes curtos do tipo cone-Morse: proporção coroa-implante

The purpose of this study was to analyze the biomechanical interactions in bone tissue between short implants and implant-supported crowns with different heights. Two models were made using the programs InVesalius 3.0, Rhinoceros 4.0 and Solidworks 2010. The models were established from a bone block with the short implant (3.75 x 8.5 mm) with geometry Morse taper connection (MT). The height of the crown (cemented) was set at 10.0 mm and 15.00 mm. The models were processed by programs and 10 NEiNastran Femap 10.0. The force applied was 200N (vertical) and 100N (oblique). The results were plotted on maps Voltage Maximum Principal. Statistical analysis was performed using ANOVA. The results showed that the increase in crown height, increased stress concentration in the crown of 15 mm under oblique loading (p <0.001), the oblique loading has significantly expanded the area of stress concentration (p <0.001). Conclusion:the increase of the crown increased the stress concentration, being statistically significant for short implants Morse taper. The mesial and distal region had the highest concentration of stresses under oblique loading. The oblique loading was more harmful when compared with axial loading, being statistically significant.

Análise Biomecânica em implantes com diferentes tipos de conexão: estudo pelo MEF-3D

The aim of this study was to evaluate the biomechanical behavior of different implant connection types, by means of three-dimensional finite element analysis. 3 Three-dimensional models were created with a graphic modeling software: SolidWorks 2006 and Rhinoceros 4.0, and InVesalius (CTI, São Paulo, Brasil), the bone was obtained by computerized tomography of a sagittal section of the molar region. The model was composed by bone block with an implant (4 x 10 mm) (Conexão Sistemas de Prótese, São Paulo), with different implant connections: external hex, internal hex and Morse-taper with the corresponding prosthetic component Ucla or Morse-taper abutment. The Three-dimensional models were transferred to finite element software Femap 10.0 (Siemens PLM Software Inc., CA, USA), to generate a mesh, boundary conditions and loading. An axial (200N) and oblique load (100N) was applied on the occlusal surface of the crowns. Analyses were performed using the finite element software NEiNastran 9.0 (Noran Engineering, Inc., USA) and transferred to the Femap 10.0 to obtain the results; after the results were visualized using von Mises stress maps and Maximum stress principal. The results showed the stress distribution was similar between models, with a little superiority of Morse-taper connection. It was concluded that: the three connection types were biomechanical viable; The Morse-taper connection presented the better internal stress distribution; there was not significant biomechanical differences on the bone.

Comportamento biomecânico dos sistemas de retenção de overdentures

Objective: to the purpose of this study was to compare the stress distribution in the peri-implant hard tissue on different attachment systems for mandibular or maxillary implant-retained overdentures. Material and methods: the search for published studies was performed on PubMed/Medline database covering the period of January 2000 to April 2014. The selection of the eligible studies was performed according to including and excluding criteria. Results: a total of 140 studies were screened and according to the search strategy, 21 studies were selected for this review. Eight studies perfomed strain-gauge analysis, 5 evaluated the stress distribution though photoelastic test and 7 performed tridimensional finite element analysis. Only one study in vivo was included. Non-splinted O-rings showed better stress distribution than other bar-clip attachment systems. Conclusions: the present study did not find sufficient evidences regarding the most indicated attachment system for overdentures with better stress distribution for the peri-implant hard tissue. The methodologies analyzed should be complemented with other tests and used as a tool for further clinical studies.

Influence of crown-to-implant ratio, retention system, restorative material, and occlusal loading on stress concentrations in single short implants

Purpose: The aim of this study was to assess the contributions of some prosthetic parameters such as crown-to-implant (C/I) ratio, retention system, restorative material, and occlusal loading on stress concentrations within a single posterior crown supported by a short implant. Materials and Methods: Computer-aided design software was used to create 32 finite element models of an atrophic posterior partially edentulous mandible with a single external-hexagon implant (5 mm wide × 7 mm long) in the first molar region. Finite element analysis software with a convergence analysis of 5% to mesh refinement was used to evaluate the effects of C/I ratio (1:1; 1.5:1; 2:1, or 2.5:1), prosthetic retention system (cemented or screwed), and restorative material (metal-ceramic or all ceramic). The crowns were loaded with simulated normal or traumatic occlusal forces. The maximum principal stress (σmax) for cortical and cancellous bone and von Mises stress (σvM) for the implant and abutment screw were computed and analyzed. The percent contribution of each variable to the stress concentration was calculated from the sum of squares analysis. Results: Traumatic occlusion and a high C/I ratio increased stress concentrations. The C/I ratio was responsible for 11.45% of the total stress in the cortical bone, whereas occlusal loading contributed 70.92% to the total stress in the implant. The retention system contributed 0.91% of the total stress in the cortical bone. The restorative material was responsible for only 0.09% of the total stress in the cancellous bone. Conclusion: Occlusal loading was the most important stress concentration factor in the finite element model of a single posterior crown supported by a short implant.

Influência do material oclusal na distribuição de tensões em próteses implantossuportadas unitárias

Objective: the aim of this study was to evaluate the influence of occlusal veneering material in single fixed implant-supported crowns through the 3-D finite element method. Material and methods: Four models were fabricated using the Rhinoceros 4.0, SolidWorks, and InVesalius softwares. Each model represented a block of mandibular bone with an external hexagon implant of 5 mm x 10 mm and different veneering materials including NiCr (1), porcelain (2), composite resin (3), and acrylic resin (4). An axial load of 200 N and an oblique load of 100 N were applied. Results: model (2) with porcelain veneering presented a lower stress concentration for the NiCr framework, followed by the composite resin and acrylic resin. The stress distribution to the implant and bone tissue was similar for all models. Conclusions: there is no difference of stress distribution to the implant and supporting structures by varying the veneering material of a single implant-supported prosthesis.

Influência do material oclusal na distribuição de tensões em próteses implantossuportadas unitárias

Objective: the aim of this study was to evaluate the influence of occlusal veneering material in single fixed implant-supported crowns through the 3-D finite element method. Material and methods: Four models were fabricated using the Rhinoceros 4.0, SolidWorks, and InVesalius softwares. Each model represented a block of mandibular bone with an external hexagon implant of 5 mm x 10 mm and different veneering materials including NiCr (1), porcelain (2), composite resin (3), and acrylic resin (4). An axial load of 200 N and an oblique load of 100 N were applied. Results: model (2) with porcelain veneering presented a lower stress concentration for the NiCr framework, followed by the composite resin and acrylic resin. The stress distribution to the implant and bone tissue was similar for all models. Conclusions: there is no difference of stress distribution to the implant and supporting structures by varying the veneering material of a single implant-supported prosthesis.

Influência do formato do rebordo alveolar sagital em reabilitações com associação de prótese parcial removível de extremidade livre e implante ósseo integrado

The association of mandibular distal extension removable partial dentures with an osteointegrated implant is a treatment option at hasn't been fully explored by modern rehabilitation dentistry yet. The objective of this study is to evaluate, by means of the bidimensional method of finite elements, the distribution of tension on the structures supporting the distal extension removable partial denture (DERPD), associated to a 10.0 x 3.75 mm osteointegrated implant with an ERA retention system, in alveolar ridges of different shapes. Eight models were created, representing, from a sagittal perspective: Model A (MA) – a half arch with a horizontal ridge without posterior support, with the presence of the lower left canine, and a conventional DERPD, with metallic support in the incisal aspect of this canine, as replacement for the first and second pre-molars and the first and second molars of the lower left half arch; Model B (MB) – similar to MA, but different because of the presence of a 3.75 x 10.00 mm implant with an associated ERA retention system in the posterior region of the DERPD base; Model C (MC) - similar to MA, however with a distally ascending ridge format; Model D (MD) – similar to MC, but different because there is an implant associated to a retention system; Model E (ME) - similar to MA, however with a distally descending ridge format; Model F (MF) – similar to ME, but ditfferent in the sense that there is an implant with an associated ERA retention system; Model G (MG) – similar to MA, however with a distally descending-ascending ridge format; Model H (MH) – similar to MG, but different in the sense that there is an implant with an associated ERA retention system. The finite element program ANSYS 9.0 was used to load the models with vertical forces of 50 N, on each cuspid tip. The format of distal descending edge (ME and MF) was that presented worse results, so in the models with conventional RPD as in the models with RPD associated to the implant and ERA system of retention, for the structures gingival mucosa and tooth support. 1) the distally descending ridge presented the most significant stress in the model with the conventional RPD (ME) or with a prosthesis associated to an implant (MF) and 2) the horizontal ridge (MB) provided more relief to the support structures, such as the tooth and the spongy bone, when there was an implant associated to an ERA retention system. The incorporation of the implants with the ERA system retention, in the posterior area of the toothless edge, it promotes larger stability and retention to PPREL, improving the patient's masticatory acting and, consequently, its comfort and function.

The influence of the alveolar ridge shape on the stress distribution in a free-end saddle removable partial denture supported by implant

The alveolar ridge shape plays an important role in predicting the demand on the support tooth and alveolar bone in the removable partial denture (RPD) treatment. However, these data are unclear when the RPD is associated with implants. This study evaluated the influence of the alveolar ridge shape on the stress distribution of a free-end saddle RPD partially supported by implant using 2-dimensioanl finite element analysis (FEA). Four mathematical models (M) of a mandibular hemiarch simulating various alveolar ridge shapes (1-distal desceding, 2- concave, 3-horizontal and 4-distal ascending) were built. Tooth 33 was placed as the abutment. Two RPDs, one supported by tooth and fibromucosa (MB) and other one supported by tooth and implant (MC) were simulated. MA was the control (no RPD). The load (50N) were applied simultaneously on each cusp. Appropriate boundary conditions were assigned on the border of alveolar bone. Ansys 10.0 software was used to calculate the stress fields and the von Mises equivalent stress criteria (σvM) was applied to analyze the results. The distal ascending shape showed the highest σvM for cortical and medullar bone. The alveolar ridge shape had little effect on changing the σvM based on the same prosthesis, mainly around the abutment tooth.

Influencia del nivel de inserción ósea del diente soporte en el desplazamiento de PPR de extremidad libre mandibular asociada al implante oseointegrado

The rehabilitation with mandibular distal extension removable partial dentures (DERPD) is complex and the use of implants has been improving the functioning of this approach. The insertion bony level around of the last support tooth is an aggravating factor, since it can harm the longevity of the treatment. Thus, the aim of this research was to evaluate the displacement tendency of a mandibular DERPD associated to an implant, with different insertion bony levels and different connections between the RPD and the support tooth, by finite element analysis. Eight models were made: MA - DERPD, incisal rest, no bony loss; MB - DERPD, distal plate, no bony loss; MC - DERPD, incisal rest, no bony loss, with implant and ERA system; MD - DERPD, distal plate, no bony loss, with implant and ERA system; ME - DERPD, incisal rest, bony loss; MF - DERPD, distal plate, bony loss; MG - DERPD, incisal rest, bony loss, with implant and ERA system; MH - DERPD, distal plate, bony loss, with implant and ERA system. Loads of 50 N in each peak were applied. Displacement maps were obtained and showed that implant favors this association and the bony loss harms the prognostic of the prosthesis. It is concluded that: the introduction of the implant with ERA system reduced the displacement tendency of the tooth and supporting structures; introduction of distal plate reduced the movement tendency of the support tooth; the decrease of the periodontal support didn't influence significantly the displacement tendency of the models with distal plate distal, but it influenced the models with distal incisal rest.

Projeto estrutural de um conector bipartido utilizado na indústria de óleo & gás através do método dos elementos finitos

Pós-graduação em Engenharia Mecânica - FEG

Cálculo em elementos finitos das frequências naturais dos modos de flexão de uma linha de eixo de unidade geradora hidráulica em escala

Pós-graduação em Engenharia Mecânica - FEG

Simulação numérica de fluxo de águas subterrâneas do aquífero Rio Claro, na região do campus da UNESP - Rio Claro, SP

The water management in any area is highly important to the success of many business and also of life and the understanding of your relationship with the environment brings better control to its demand. I.e. hydrogeological studies are needed under better understanding of the behavior of an aquifer, so that its management is done so as not to deplete or harm it. The objective of this work is the numerical modeling in transient regime of a portion of the Rio Claro aquifer formation in order to get answers about its hydrogeological parameters, its main flow direction and also its most sensitive parameters. A literature review and conceptual characterization of the aquifer, combined with field campaigns and monitoring of local water level (NA), enabled the subsequent construction of the mathematical model by finite elements method, using the FEFLOW 6.1 ® computational algorithm. The study site includes the campus of UNESP and residential and industrial areas of Rio Claro city. Its area of 9.73 km ² was divided into 318040 triangular elements spread over six layers, totaling a volume of 0.25 km³. The local topography and geological contacts were obtained from previous geological and geophysical studies as well as profiles of campus wells and SIAGAS / CPRM system. The seven monitoring wells on campus were set up as observation points for calibration and checking of the simulation results. Sampling and characterization of Rio Claro sandstones shows up a high hydrological and lithological heterogeneity for the aquifer formation. The simulation results indicate values of hydraulic conductivity between 10-6 and 10-4 m / s, getting the Recharge/Rainfall simulation in transient ratio at 13%. Even with the simplifications imposed on the model, it was able to represent the fluctuations of local NA over a year of monitoring. The result was the exit of 3774770 m³ of water and the consequently NA fall. The model is considered representative for the...

Análise da influência de variantes do método de solução de escoamentos utilizando os métodos de elementos finitos com compressibilidade artificial e pseudo-características

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Projeto de um tanque de armazenamento atmosférico com teto flutuante para estocagem de gasolina

In this paper are discussed the main project stages of an atmospheric storage tank with floating roof. It emphasizes the calculations of the bottom, the shell and the floating roof, discussing its stages and conditions, based on the technical standards of the project. The storage tanks are static equipment working under low pressure and has an essential importance for the operation of a process plant. This paper has the purpose of obtaining the dimensions and materials of each component of the tank through the calculations and prove them with results obtained by numerical simulation by finite elements with the help of Autodesk Inventor software, consolidating the project