scholarly journals A Numerical Study on Optimum Material and Design for Dental Trilayer Systems

2021 ◽  
Vol 5 (2) ◽  
pp. 36-44
Author(s):  
Ebrahim Maghami ◽  
Ehsan Homaei
Keyword(s):  
Critical Loads ◽  
Numerical Study ◽  
Metal Layer ◽  
Compressive Loading ◽  
Damage Mechanism ◽  
Extended Finite Element ◽  
Damage Initiation ◽  
System A ◽  
Optimum Material ◽  
Radial Cracks

This study investigated the impacts of geometry, thickness, and material on damage growth in a porcelain-metal restoration structure by utilizing a computational approach. Extended finite element method (XFEM) was used to find the critical loads causing the nucleation of radial cracks at the porcelain undersurface. Plastic deformation also was considered at the metal above the surface as another damage mechanism. The dental system consisted of a brittle outerlayer (porcelain)/metal (Pd/Co/Au alloys)-core/dentin-substrate trilayer system. A tungsten-carbide hemisphere as an indenter was used to apply a compressive loading on the structure. In addition, two different geometries were created to present the dental structure, cylinder, and tapered cylinder. The results showed that a harder and stiffer metal core can resist the initiation of radial cracks. It was also observed that the metal with thinner layers is more vulnerable to radial cracking. In all simulations, the tapered cylinder geometry showed to have higher critical loads in both damage modes. The optimum thickness for the porcelain layer was suggested to be 0.5 mm. The geometry of dental crown-like structures was found to be an important factor in damage initiation. The findings also proposed that the metal layer should not be designed very thin in order to prevent the formation of radial cracks. This numerical investigation also recommended that the stiffness of the metal layer is better to keep higher compared to other layers to hinder the initiation of radial cracks.

Mean flow and turbulence statistics through a sluice gate in a navigation lock system: A numerical study

2020 ◽  
Vol 84 ◽  
pp. 155-163
Author(s):  
C.C. Battiston ◽  
F.A. Bombardelli ◽  
E.B.C. Schettini ◽  
M.G. Marques
Keyword(s):  
Numerical Study ◽  
Mean Flow ◽  
Turbulence Statistics ◽  
Sluice Gate ◽  
System A ◽  
Navigation Lock

scholarly journals Simulation of thermal cycle aging process on fiber-reinforced polymers by extended finite element method

2017 ◽  
Vol 52 (14) ◽  
pp. 1947-1958 ◽  
Author(s):  
Sergio González ◽  
Gianluca Laera ◽  
Sotiris Koussios ◽  
Jaime Domínguez ◽  
Fernando A Lasagni
Keyword(s):  
Finite Element ◽  
Degradation Process ◽  
Damage Mechanism ◽  
Fiber Reinforced Polymers ◽  
Model Parameters ◽  
Suitable Model ◽  
Fiber Reinforced ◽  
Aging Effects ◽  
Extended Finite Element ◽  
Element Analysis

The simulation of long life behavior and environmental aging effects on composite materials are subjects of investigation for future aerospace applications (i.e. supersonic commercial aircrafts). Temperature variation in addition to matrix oxidation involves material degradation and loss of mechanical properties. Crack initiation and growth is the main damage mechanism. In this paper, an extended finite element analysis is proposed to simulate damage on carbon fiber reinforced polymer as a consequence of thermal fatigue between −50℃ and 150℃ under atmospheres with different oxygen content. The interphase effect on the degradation process is analyzed at a microscale level. Finally, results are correlated with the experimental data in terms of material stiffness and, hence, the most suitable model parameters are selected.

Applicability of thermal response tests in designing standing column well system: A numerical study

Energy ◽  
2016 ◽  
Vol 109 ◽  
pp. 679-693 ◽  
Author(s):  
Jun-Seo Jeon ◽  
Seung-Rae Lee ◽  
Woo-Jin Kim
Keyword(s):  
Numerical Study ◽  
Thermal Response ◽  
System A

scholarly journals Multi-configuration Stiffened Panels under Compressive Load: Part 1 – Theoretical Analysis

2018 ◽  
Vol 7 (3.11) ◽  
pp. 38
Author(s):  
Ramzyzan Ramly ◽  
Wahyu Kuntjoro ◽  
Amir Radzi Abdul Ghani ◽  
Rizal Effendy Mohd Nasir ◽  
Zulkifli Muhammad
Keyword(s):  
Theoretical Analysis ◽  
Experimental Analysis ◽  
Critical Loads ◽  
Input Parameter ◽  
Compressive Loading ◽  
Compressive Load ◽  
Cross Sectional ◽  
Stiffened Panels ◽  
Compression Load ◽  
Main Input

Stiffened panels are the structure used in the aircraft wing skin panels. Stiffened panels are often critical in compression load due to its thin structural configuration. This paper analyzes the critical loads of a multi configuration stiffened panels under axial compressive loading. The study comprised three main sections; theoretical analysis, numerical analysis and experimental analysis. The present paper deals only with the theoretical analysis. This first part of analysis is very important since the results will be the main input parameter for the subsequent numerical and experimental analysis. The analysis was done on the buckling properties of the panels. Four panel configurations were investigated. Results showed that even though the stiffened panels have the same cross-sectional area, their critical loads were not identical.   

scholarly journals Numerical Study of Fracture Characteristics of Deep Granite Induced by Blast Stress Wave

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Zheming Zhu ◽  
Weiting Gao ◽  
Duanying Wan ◽  
Meng Wang ◽  
Yun Shu
Keyword(s):  
Shear Failure ◽  
Numerical Study ◽  
Numerical Models ◽  
Rock Fracture ◽  
Initial Pressure ◽  
3D Models ◽  
In Situ Stress ◽  
Vertical Pressure ◽  
The Difference ◽  
Radial Cracks

To study the characteristics of rock fracture in deep underground under blast loads, some numerical models were established in AUTODYN code. Weibull distribution was used to characterize the inhomogeneity of rock, and a linear equation of state was applied to describe the relation of pressure and volume of granite elements. A new stress initialization method based on explicit dynamic calculation was developed to get an accurate stress distribution near the borehole. Two types of in situ stress conditions were considered. The effect of heterogeneous characteristics of material on blast-induced granite fracture was investigated. The difference between 2D models and 3D models was discussed. Based on the numerical results, it can be concluded that the increase of the magnitude of initial pressure can change the mechanism of shear failure near the borehole and suppress radial cracks propagation. When initial lateral pressure is invariable, with initial vertical pressure rising, radial cracks along the acting direction of vertical pressure will be promoted, and radial cracks in other directions will be prevented. Heterogeneous characteristics of material have an obvious influence on the shear failure zones around the borehole.

PROGRESSIVE DAMAGE FAILURE ANALYSIS OF POST-BUCKLED COMPOSITE SINGLE-STRINGER PANEL WITH TEFLON INSERTS

2021 ◽  
Author(s):  
VIJAY K. GOYAL ◽  
AUSTIN PENNINGTON ◽  
JASON ACTION
Keyword(s):  
Experimental Data ◽  
Composite Structures ◽  
Laminated Composites ◽  
Compressive Loading ◽  
Weight Ratio ◽  
High Strength ◽  
Material Model ◽  
Stiffened Panels ◽  
Damage Initiation ◽  
Critical Aspects

The high strength-to-weight and stiffness-to-weight ratio materials, such as laminated composites, are advantageous for modern aircraft. Laminated composites with initial flaws are susceptible to delamination under buckling loads. PDA tools help enhance the industry’s understanding of the mechanisms for damage initiation and growth in composite structures while assisting in the design, analysis, and sustainment methods of these composite structures. The global-local modeling approach for the single-stringer post-buckled panel was evaluated through this effort, using Teflon inserts to simulate the defect of damage during manufacturing. This understanding is essential for designing the post-buckled structure, reducing weight while predicting damage initiation location, and addressing a potential design review for future aircraft repairs. In this work, the initial damage was captured with Teflon inserts as the starting configuration; and any reference to the damage initiation refers to any damage beyond the “initial unbonded region.” The effort aims to develop, evaluate, and enhance methods to predict damage initiation and progression and the failure of post-buckled hat-stiffened panels using multiple Abaqus FEA Virtual Crack Closure Technique (VCCT) definitions. Validation of the PDA using the VCCT material model was performed on a large single-stringer panel subjected to compressive loading. The compressive loading of the panel caused the skin to buckle before any damage began to occur locally. In addition, comparisons are made for critical aspects of the damage morphology, such as a growth pattern that included delamination from the skin-stiffener interface to the skin and ply interfaces. When compared against the experimental data produced through the NASA Advanced Composites Project (ACP), the present model captured damage migration from one surface to another, and model validations were ~5% of the experimental data.

Effect of Guide Vane Shape on Duct Flow Characteristics in a Flue-Gas Desulfurization System : A Numerical Study

2018 ◽  
Vol 42 (3) ◽  
pp. 243-250
Author(s):  
Hyeong Rae Kim ◽  
In Sik Hwang ◽  
Sang Shin Park ◽  
Jee Eun Min ◽  
Jungho Hwang
Keyword(s):  
Flue Gas ◽  
Numerical Study ◽  
Guide Vane ◽  
Flow Characteristics ◽  
Flue Gas Desulfurization ◽  
Duct Flow ◽  
System A

Gas–solid two-phase flow in an underground mine with an optimized air-curtain system: A numerical study

2020 ◽  
Vol 140 ◽  
pp. 137-150 ◽  
Author(s):  
Changgeng Gui ◽  
Fan Geng ◽  
Junhua Tang ◽  
Hongwei Niu ◽  
Fubao Zhou ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Numerical Study ◽  
Underground Mine ◽  
Phase Flow ◽  
Two Phase ◽  
Air Curtain ◽  
System A
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