scholarly journals MODELING OF SELF–HEALING MATERIALS AND FITTING PARAMETERS PROCEDURE

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Dejan Petrović ◽  
Milica Obradović ◽  
Miloš Radović ◽  
Aleksandar Jovanović ◽  
Snežana Jovanović ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Diffusion Coefficient ◽  
Materials Science ◽  
Surface Defects ◽  
Self Healing ◽  
Risk Map ◽  
Fitting Procedure ◽  
Determine Diffusion Coefficient ◽  
Fitting Parameters

The surface defects of the material are difficult to detect and difficult to repair. A big challenge in materials science is to design „smart“ synthetic systems that can re-establish the continuity and integrity of the damaged area. Recent research of the nanocontainers with the process of self-healing materials promises a good avenue for new smart nanocoating interfaces. We use continuum modeling approach to investigate coating substrates that contain nanoscale defects with healing agents. Here we use Finite Element Method (FEM) with different diffusivity and fluxes. The fitting procedure from simulations is performed to determine diffusion coefficient and the diameter of nanocontainers to match experimental results. We also show the risk map from the calculations of the creepage and coverage.

B-Spline Wavelet-Based Finite Element Vibration Analysis of Composite Pipes with Internal Surface Defects of Different Geometries

2017 ◽  
Vol 17 (04) ◽  
pp. 1750051 ◽  
Author(s):  
Wasiu A. Oke ◽  
Yehia A. Khulief
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Vibration Analysis ◽  
Surface Defects ◽  
Internal Surface ◽  
Spline Wavelet ◽  
B Spline ◽  
Composite Pipe ◽  
Composite Pipes ◽  
Element Method

The vibration analysis of composite pipes with internal wall defects due to erosion-induced surface degradation is investigated. The surface defects are treated as discontinuities. The geometry of the discontinuity is permitted to vary within the cross-section both in the angular and radial directions, and to occupy any length of the pipe span. A B-spline wavelet-based finite element method (BWFEM) that takes advantage of the localization properties of wavelets is invoked; thus utilizing its effectiveness in modeling of crack problems and local damages. The composite pipe was treated as beam elements that obey the Euler–Bernoulli beam theory. Unlike the conventional finite element method (FEM), the developed BWFEM uses fewer elements without compromising the accuracy. Numerical simulations are performed to demonstrate the accuracy and efficiency of the developed element through comparison with available results in the literature, as well as results obtained using ANSYS. Some benchmark solutions are obtained for the composite pipe with internal surface defects of different geometries.

Tailoring of self-healing thermal barrier coatings via finite element method

2018 ◽  
Vol 431 ◽  
pp. 60-74 ◽  
Author(s):  
L. Wang ◽  
F. Shao ◽  
X.H. Zhong ◽  
J.X. Ni ◽  
K. Yang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Self Healing ◽  
Barrier Coatings ◽  
Element Method

Design and optimization of coating structure for plasma sprayed self-healing MgO coating via finite element method

2021 ◽  
Vol 47 (2) ◽  
pp. 2414-2429
Author(s):  
Mingxiang Zhuang ◽  
Jianhui Yuan ◽  
Zhongchao Hu ◽  
Guangshu Li ◽  
Huanyu Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Self Healing ◽  
Coating Structure ◽  
Design And Optimization ◽  
Plasma Sprayed ◽  
Element Method

scholarly journals Circumferential defect detection using ultrasonic guided waves

2020 ◽  
Vol 37 (6) ◽  
pp. 1923-1943 ◽  
Author(s):  
Yihui Da ◽  
Guirong Dong ◽  
Yan Shang ◽  
Bin Wang ◽  
Dianzi Liu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Guided Waves ◽  
Surface Defects ◽  
Ultrasonic Guided Waves ◽  
Content Type ◽  
Dispersion Equations ◽  
Circular Annulus ◽  
Equidistant Surface ◽  
Element Method

Purpose Quantitatively detecting surface defects in a circular annulus with high levels of accuracy and efficiency has been paid more attention by researchers. The purpose of this study is to investigate the theoretical dispersion equations for circumferential guided waves and then develop an efficient technique for accurate reconstruction of defects in pipes. Design/methodology/approach The methodology applied to determine defects in pipelines includes four steps. First, the theoretical work is carried out by developing the appropriate dispersion equations for circumferential guided waves in a pipe. In this phase, formulations of strain-displacement relations are derived in a general equidistant surface coordinate. Following that, a semi-analytical finite element method (SAFEM) is applied to solve the dispersion equations. Then, the scattered fields in a circular annulus are calculated using the developed hybrid finite element method and simulation results are in accord with the law of conservation of energy. Finally, the quantitative detection of Fourier transform (QDFT) approach is further enhanced to efficiently reconstruct the defects in the circular annuli, which have been widely used for engineering applications. Findings Results obtained from four numerical examples of flaw detection problems demonstrate the correctness of the developed QDFT approach in terms of accuracy and efficiency. Reconstruction of circumferential surface defects using the extended QDFT method can be performed without involving the analytical formulations. Therefore, the streamlined process of inspecting surface defects is well established and this leads to the reduced time in practical engineering tests. Originality/value In this paper, the general dispersion equations for circumferential ultrasonic guided waves have been derived using an equidistant surface coordinate and solved by the SAFEM technique to discover the relationship between wavenumber of a wave and its frequency. To reconstruct defects with high levels of accuracy and efficiency, the QDFT approach has been further enhanced to inspect defects in the annular structure.

scholarly journals Simulation of Chloride Ingress through Surface-Coated Concrete during Migration Test Using Finite-Difference and Finite-Element Method

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Seyoon Yoon
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Diffusion Coefficient ◽  
Finite Difference ◽  
Polymer Surface ◽  
Ionic Concentration ◽  
Surface Coatings ◽  
Chloride Ingress ◽  
Simulation Results ◽  
Element Method

Polymer surface coatings are commonly used to enhance the corrosion resistance of concrete structures in saline environments to ionic diffusivity; this diffusivity can be determined by migration tests. This paper presents the simulation of the effects of the surface coatings on migration tests by solving the Nernst-Planck/Poisson model using both finite-difference method and finite-element method. These two numerical methods were compared in terms of their accuracy and computational speed. The simulation results indicate that the shapes of ionic profiles after migration tests depend on the effectiveness of surface coatings. This is because highly effective surface coatings can cause a high ionic concentration at the interface between coating and concrete. The simulation results were also compared to homogenized cases where a homogenized diffusion coefficient is employed. The result shows that the homogenized diffusion coefficient cannot represent the diffusivity of the surface-coated concrete.

Numerical Simulation of Carburization and Decarburization Profiles in Steels

2006 ◽  
Vol 258-260 ◽  
pp. 366-371 ◽  
Author(s):  
M. Stasiek ◽  
Andreas Öchsner
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Diffusion Coefficient ◽  
Simulation Tool ◽  
The Finite Element Method ◽  
Program System ◽  
Depth Profiles ◽  
Economic Significance ◽  
Operation Control

Due to economic significance, industry demands on mathematical models, which allow for the prediction of realistic carburization and decarburization depth profiles. Analytical solutions of Fick’s law, however, are of limited aptitude, as the concentration dependence of the diffusion coefficient of carbon in steel cannot be considered. Thus, the present paper presents a numerical simulation tool based on the finite element method (FEM). A widespread commercially available program system was used to ensure industrial applicability and to make a contribution to the standardizing of operation control.

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