Hyun Kyu Shin¹, Ha Young Kim², Sang Hyo Lee^3,*

CMC-Computers, Materials & Continua, Vol.70, No.3, pp. 5059-5071, 2022, DOI:10.32604/cmc.2022.017262

Abstract The durability performance of reinforced concrete (RC) building structures is significantly affected by the corrosion of the steel reinforcement due to chloride penetration, thus, the chloride ion diffusion coefficient should be investigated through experiments or theoretical equations to assess the durability of an RC structure. This study aims to predict the chloride ion diffusion coefficient of concrete, a heterogeneous material. A convolutional neural network (CNN)-based regression model that learns the condition of the concrete surface through deep learning, is developed to efficiently obtain the chloride ion diffusion coefficient. For the model implementation to determine the chloride ion diffusion coefficient, concrete… More >

Yang Wang¹, Hanxi Wang^2,*, Linwei Yang¹, Li Qian¹

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.4, pp. 845-857, 2021, DOI:10.32604/fdmp.2021.015961

Abstract In order to analyze the coupled influence of temperature and humidity on early-age concrete (including cement and copper tailings), a mathematical model is introduced on the basis of the Krstulovic-Dabic hydration reaction kinetic equations. In such a framework, the influence of hydration-released heat and water consumption are also taken into account. The results provided by such a model are verified by means of experiments and related sensor measurements. The research results show that this model can adequately predict the internal temperature and the humidity temporal evolution laws. More >

Tadashi Kasuya^1,*, A. Toshimitsu Yokobori Jr², Nobuyuki Ishikawa³, Manabu Enoki¹, Satoshi Minamoto⁴

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.2, pp. 120-120, 2019, DOI:10.32604/icces.2019.05227

Abstract Weld cold cracking is categorized as hydrogen cracking. To assess cold cracking susceptibility of steel HAZ (heat affected zone), it is necessary to estimate local hydrogen content and residual stress at a weld root that are in general numerically calculated by FEM and/or FDM. To conduct numerical calculations, physical and mechanical properties such as diffusion coefficient of hydrogen in steel are necessary. In this work, we have developed empirical formulae to calculate HAZ hardness, hydrogen diffusion coefficient and tensile properties. The present empirical formula of HAZ hardness is expressed using chemical compositions of a welded steel and weld thermal history.… More >

Chung-Fu Chen¹, Yi-Chia Cheng¹, Che-Wun Hong^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.3, pp. 263-283, 2015, DOI:10.3970/cmes.2015.109.263

Abstract Based on the Hellmann-Feynman theorem, which integrates the molecular dynamics simulation with computational quantum mechanics, this research simulates the ionic transport in the LiCl-KCl molten salt materials using so called “first principles molecular dynamics (FPMD)” technique without employing an empirical potential model. The main purpose of this computational FPMD focuses on the evaluation of important transport properties, such as diffusion coefficient, ionic conductivity, shear viscosity, and thermal conductivity, using the Green-Kubo relationship. All simulation results agree well with experimental data published in existing literatures within an acceptable range. FPMD calculations are proved to be a powerful tool for prediction of… More >

Kentaro Doi^1,2, Yuzuru Chikasako¹, Satoyuki Kawano^1,3

FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.1, pp. 1-26, 2015, DOI:10.3970/fdmp.2015.011.001

Abstract Propylene carbonate (PC) and ethylene carbonate are known as good candidates of organic solvents to be used in Li-ion rechargeable batteries, since Li⁺ ions exhibit preferable charge-discharge characteristics with such solvents. On the other hand, polar solvents usually form solvation shells with solute ions, and cause a drastic reduction of ionic conductivity. Along these lines, there has been a curious question why the diffusion coefficient D_Li of Li⁺ strongly depends on the salt concentration. In the present study, a theoretical model is developed on the basis of the Langevin equation in which the interactions between ions and solvent molecules are… More >