Fabien Briffod*, Alexandre Bleuset, Takayuki Shiraiwa, Manabu Enoki

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.2, pp. 125-125, 2019, DOI:10.32604/icces.2019.05319

Abstract The fatigue behavior of metallic materials is a multi-scale problem (from a time and length-scale perspective) intimately influenced by microstructural features that determine the early stages of crack propagation. Prediction of fatigue life is traditionally based on the evaluation of macroscopic mechanical fields at the structure level and on the application of empirical rules. However, these structure-oriented methods are material-specific and do not consider the material variability at lower scales. Hence, reliable prediction of fatigue performances and its variability requires on one side the characterization and quantification of early damage mechanisms and on the other side the incorporation of local… More >

Takayuki Shiraiwa*, Fabien Briffod, Manabu Enoki

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.2, pp. 124-124, 2019, DOI:10.32604/icces.2019.05311

Abstract The purpose of this study is to evaluate fatigue performances of welded structures using numerical simulations. The fatigue life of welded joint is complicatedly affected by various factors such as geometries, defects, residual stress and microstructure. Conventional fatigue life assessments are generally based on fracture mechanics and predict the fatigue life for long crack propagation. In order to predict the total fatigue life more accurately, it is necessary to consider the lifetime for crack initiation and microstructually short crack (MSC) growth. In this study, a numerical framework to predict the fatigue life including crack initiation, MSC growth and long crack… More >

Masahiko Demura^1,*, Junya Sakurai^1,2, Masayoshi Yamazaki¹, Junya Inoue^1,2

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.2, pp. 123-123, 2019, DOI:10.32604/icces.2019.05303

Abstract Creep is a complicated and time-dependent phenomenon, which is affected by the initial state and the degradation of microstructures. It is thus considered that the information about the microstructure is essential to predict the creep rupture time. On the other hand, there is a strong, practical need for the prediction without the investigation of microstructures nor the disclosure of the detailed process that should control the initial microstructures. In this study, we examined how modern machine learning technique can help to predict the creep rupture time in heat-resistant ferrite-type steels without the direct information about the microstructures and the process… More >

Dmitry S. Bulgarevich^1,*, Susumu Tsukamoto¹, Tadashi Kasuya², Masahiko Demura¹, Makoto Watanabe^1,3

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.2, pp. 122-122, 2019, DOI:10.32604/icces.2019.05271

Abstract The microstructure of steel greatly determines its mechanical properties/performance and holds information on chemical composition and processing history. Therefore, quantitative analysis of optical or SEM images on formed microstructure phases is one of the primary interests for metallurgy. So far, such analyses in laboratories are done manually by experts and are very time consuming. However, with modern microscopy techniques of automated image acquisitions over the large imaging areas and even by using of sample slicing for three-dimensional imaging, the amount of image data could be overwhelming for manual examinations. In this respect, there is a possibility that machine learning (ML)… More >

Hitoshi Izuno¹, Masahiko Demura^1,*, Masaaki Tabuchi², Yohichi Mototake³, Masato Okada^1,3

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.2, pp. 121-121, 2019, DOI:10.32604/icces.2019.05270

Abstract An accurate creep deformation model is needed for detailed description of creep behavior of high temperature structural materials, e.g., Grade 91 steels used in boiler tubes of thermal power plants. Two types of creep constitutive equations are known, as follows: the one, e.g., modified theta method, assumes the existence of a steady state; and the other, e.g., theta method, does not. So far, both types have been selected on a case by case basis and there is no consensus on whether or not the steady state should be assumed even if limited in the Grade 91 steels. In this study,… More >

Seung Kyo Lee, Dongil Chu, Eun Kyu Kim^*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.4, pp. 93-93, 2019, DOI:10.32604/icces.2019.04995

Abstract We studied on a liquid exfoliation technique for the robust production of transition metal dichalcogenides (TMDC) thin films, because this technique has advantages for residue-free, large-scale, and low-cost fabrication. During the process of liquid exfoliation, a mixture of DI water and ethanol was used to obtain higher concentrations of TMDC flakes in the solution compared to that in water-based solution. The film thicknesses were controlled by a two-step centrifuge process to analyze the influence on the photovoltaic properties with gold/TMDC/silicon geometry. Based on ultraviolet photoelectron spectroscopy measurement results, the energy band diagram of the devices using MoS₂ and WS₂ films… More >

Guiping Liu^*, Sheng Liu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.4, pp. 92-92, 2019, DOI:10.32604/icces.2019.05523

Abstract In engineering multi-objective optimization of structures, the parameters involved in the problems are usually given deterministic values. However, due to the presence of manufacturing and measurement errors, uncertainty inevitably exists in the geometrical properties of the structure, the material properties, the boundary conditions, etc. For uncertain problems, the interval optimization methods are widely used. They describe the uncertainty by intervals which only need to find the upper and lower bounds of the uncertain parameters instead of constructing the exact probability distribution function. However, in multi-objective optimization problems, if considered all the upper and lower bounds of the objective functions as… More >

Bingyu Ni, Chao Jiang^*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.4, pp. 91-91, 2019, DOI:10.32604/icces.2019.05517

Abstract Uncertain parameters with inherent spatial variability are commonly encountered in engineering. These include material properties of the heterogeneous media such as concrete or porous rock, external loads such as wind or snow loads applied on structures, etc. This type of uncertain parameters is traditionally quantified by the random field model, while the large amount of information required in construction of the precise probability distribution functions is often difficult to obtain for many practical engineering problems. The authors propose an interval field model to represent the spatial uncertainties with insufficient information, in which the variation of the parameter at any location… More >

Hideo Matsufuru^1,*, Kohsuke Sumiyoshi²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.4, pp. 90-90, 2019, DOI:10.32604/icces.2019.05390

Abstract The core collapse supernovae are one of key phenomena to understand the history of the Universe and the origin of heavy elements. To understand their explosion mechanism, large scale numerical simulations are essential that require to solve a multi-physics system described by coupled equations of hydrodynamics and neutrino-radiation transfer in multidimensions. Since the neutrino transfer is governed by the Boltzmann equation in six-dimensional space, necessary computational resource rapidly increases as the number of grids in simulations grows. So far numerical studies have been performed mostly on massively parallel computers and only a few studies have been made using accelerator architectures,… More >

Ye Chen, Yonghai Gao, Guizhen Xin, Wang Yao, Dongzhi Gao, Litao Chen, Baojiang Sun^*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.4, pp. 88-89, 2019, DOI:10.32604/icces.2019.05522

Abstract Natural gas hydrate is regarded as a kind of potential alternative energy resource and attracts the attention all over the world. Geological surveys have found that most natural gas hydrates are buried at the bottom of the sea. Several development methods, such as depressurization, thermal stimulation and inhibitor injection are proposed gradually on the basis of hydrate special properties, obtaining certain trial-produce performance. It is of great significance to learn the flow rules underground for production safety guarantee and efficiency improvement. However, the special phase transition of hydrate between solid and fluid accompanied by energy and mass change makes it… More >