Numerical Prediction of Influence of Diamond Burs on Subsurface Damage in Intraoral Adjustments of Porcelain Prostheses

2008 ◽  
Vol 32 ◽  
pp. 203-206
Author(s):  
Xiao Fei Song ◽  
Ling Yin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Modeling ◽  
Material Removal ◽  
High Speed ◽  
Surface Damage ◽  
Subsurface Damage ◽  
Element Analysis ◽  
Made In

Failure rate is noticeably high in dental bioceramics for restorations even though progress has been made in reinforcement of the materials. One of the major causes of failures is due to surface and subsurface damage induced in intraoral adjustments. This process is a routine clinical procedure for marginal and occlusal fit using high-speed dental handpieces and diamond burs. Material removal using the diamond burs easily produce surface and subsurface damage in ceramic prostheses. Therefore, it is essential to minimize the surface damage in clinical dentistry. In this paper, we investigated the effect of diamond burs with coarse, medium and fine grit sizes on the degrees of subsurface damage in in vitro dental adjustments via numerical modeling. Finite element analysis was applied to model the dental adjusting processes and to predict the degrees of subsurface damage using different grit sizes of diamond burs.

scholarly journals Tentative Investigations on Reducing the Edge Effects in Pre-Polishing the Optics

2020 ◽  
Vol 10 (15) ◽  
pp. 5286
Author(s):  
Xiaolong Ke ◽  
Lei Qiu ◽  
Chunjin Wang ◽  
Zhenzhong Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Edge Effect ◽  
Edge Effects ◽  
Material Removal ◽  
Processing Time ◽  
Grinding Process ◽  
Element Analysis ◽  
Edge Zone ◽  
The Finite Element Analysis

The material removal depth in the pre-polishing stage of the precision optics is usually tens of microns to remove the subsurface damage and grinding marks left by the previous grinding process. This processing of the upstand edge takes a large part of the time at this stage. The purpose of this paper is to develop a method that can reduce the edge effect and largely shorten the processing time of the pre-polishing stage adopting the semirigid (SR) bonnet. The generation of the edge effect is presented based on the finite element analysis of the contact pressure at the edge zone firstly. Then, some experimentations on the edge effect are conducted, and the results proved that the SR bonnet tool can overhang the workpiece edge in the pre-polishing stage to reduce the width and height of the upstand edge to largely shorten the subsequent processing time of it. In addition, there exists a perfect overhang ratio, which generates the upstand edge with the smallest width and height, with no damage to the bonnet tool in the meantime. In addition, one combination of the pre-polishing parameters is concluded according to this method, which can be safely adopted in practical process.

Finite-Element Analysis of the Magnetostatic Field of a Coaxial Magnetic Gear Device

2015 ◽  
Vol 764-765 ◽  
pp. 289-293
Author(s):  
Yi Chang Wu ◽  
Han Ting Hsu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Magnetic Flux ◽  
High Speed ◽  
Field Analysis ◽  
Element Analysis ◽  
Magnetostatic Field ◽  
Speed Reduction ◽  
Dimensional Finite Element ◽  
Magnetic Gear

This paper presents the magnetostatic field analysis of a coaxial magnetic gear device proposed by Atallah and Howe. The structural configuration and speed reduction ratio of this magnetic gear device are introduced. The 2-dimensional finite-element analysis (2-D FEA), conducted by applying commercial FEA software Ansoft/Maxwell, is performed to evaluate the magnetostatic field distribution, especially for the magnetic flux densities within the outer air-gap. Once the number of steel pole-pieces equals the sum of the pole-pair numbers of the high-speed rotor and the low-speed rotor, the coaxial magnetic gear device possesses higher magnetic flux densities, thereby generating greater transmitted torque.

Mechanical and Optimization Analyses for Novel Wound Composite Axial Impeller

2009 ◽  
Author(s):  
Jifeng Wang ◽  
Qubo Li ◽  
Norbert Mu¨ller
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Speed ◽  
High Performance ◽  
Low Cost ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Loading Conditions ◽  
Element Analysis ◽  
Wound Composite

A mechanical and optimal analyses procedure is developed to assess the stresses and deformations of Novel Wound Composite Axial-Impeller under loading conditions particular to centrifuge. This procedure is based on an analytical method and Finite Element Analysis (FEA, commercial software ANSYS) results. A low-cost, light-weight, high-performance, composite turbomachinery impeller from differently designed patterns will be evaluated. Such impellers can economically enable refrigeration plants using water as a refrigerant (R718). To create different complex patterns of impellers, MATLAB is used for creating the geometry of impellers, and CAD software UG is used to build three-dimensional impeller models. Available loading conditions are: radial body force due to high speed rotation about the cylindrical axis and fluid forces on each blade. Two-dimensional plane stress and three-dimensional stress finite element analysis are carried out using ANSYS to validate these analytical mechanical equations. The von Mises stress is investigated, and maximum stress and Tsai-Wu failure criteria are applied for composite material failure, and they generally show good agreement.

Damage Length Predictor for High-Speed Craft

1999 ◽  
Vol 36 (04) ◽  
pp. 203-210
Author(s):  
Steven P. McGee ◽  
Armin Troesch ◽  
Nickolas Vlahopoulos
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
High Speed ◽  
Historical Data ◽  
Element Analysis ◽  
Damage Prediction ◽  
Structural Layout ◽  
Vessel Speed ◽  
Indenter Geometry

In 1994 the International Maritime Organization adopted the Code of Safety for High-Speed Craft (HSC Code). After two years of use, several shortfalls were found, one being the damage length predictor, which is based on traditional steel, mono-hulled vessels. Other damage predictors were developed based on historical data, but they do not account for variables such as aluminum or fiberglass construction, transverse members, indenter geometry variation, or for the case where the vessel comes to rest on the grounding object. This paper proposes a damage prediction model based on material properties, structural layout, grounding object geometry, and vessel speed. The model incorporates four grounding mechanisms: plate cutting, plate tearing, crushing of plate behind transverse members, and transverse member failure. The method is used to determine the resistance energy, compared to the kinetic energy, of the vessel, to determine an effective damage length. Finite-element analysis was used to model the failure of both aluminum and steel transverse members with significant differences in the results. It was found that the transverse members provided the majority of the resistance energy in one grounding mechanism and negligible resistance energy in another.

Influence of block-out on retentive force of thermoplastic resin clasps: an in vitro experimental and finite element analysis

2019 ◽  
Vol 63 (3) ◽  
pp. 303-308 ◽  
Author(s):  
Toshiki Yamazaki ◽  
Natsuko Murakami ◽  
Shizuka Suzuki ◽  
Kazuyuki Handa ◽  
Masaru Yatabe ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermoplastic Resin ◽  
Element Analysis ◽  
Retentive Force
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