Modeling and Numerical Simulation of Material Science

Journal Information
ISSN / EISSN : 2164-5345 / 2164-5353
Current Publisher: Scientific Research Publishing, Inc. (10.4236)
Former Publisher:
Total articles ≅ 102
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Windé Nongué Daniel Koumbem, Issaka Ouédraogo, Wend Dolean Arsène Ilboudo, Pèlèga Florent Kieno
Modeling and Numerical Simulation of Material Science, Volume 11, pp 35-46; doi:10.4236/mnsms.2021.112003

Abstract:
The thermal performance of three roofing models: tile, corrugated and earth terrace is numerically analyzed. The mathematical equations which govern the three roofing models are established by the electrical method of analogies. These equations are discretized by an implicit finite difference method and solved by the Gauss-Seidel algorithm. We analyze the influences of geometric parameters (Xlo, Xlarg, α and Ep) on the evolution of the temperatures of the different environments of our three roof models. In particular, we have shown that the effectiveness of a roof in reducing the temperature inside a room is linked to its physical properties. The results obtained that for the same geometric parameters, the earth roof terrace and the earth tile roof compared to the corrugated metal roof improve thermal comfort by lowering the interior temperature of 5ºC and 4.6ºC.
Abu Bakar Siddique, Tariq Khraishi
Modeling and Numerical Simulation of Material Science, Volume 11, pp 1-18; doi:10.4236/mnsms.2021.111001

Abstract:
Simulation of dislocation dynamics opens the opportunity for researchers and scientists to observe in-depth many plastic deformation phenomena. In 2D or 3D media, modeling of physical boundary conditions accurately is one of the keys to the success of dislocation dynamics (DD) simulations. The scope of analytical solutions is restricted and applies to specific configurations only. But in dynamics simulations, the dislocations’ shape and orientation change over time thus limiting the use of analytical solutions. The authors of this article present a mesh-based generalized numerical approach based on the collocation point method. The method is applicable to any number of dislocations of any shape/orientation and to different computational domain shapes. Several verifications of the method are provided and successful implementation of the method in 3D DD simulations have been incorporated. Also, the effect of free surfaces on the Peach-Koehler force has been computed. Lastly, the effect of free surfaces on the flow stress of the material has been studied. The results clearly showed a higher force with increased closeness to the free surface and with increased dislocation segment length. The simulations’ results also show a softening effect on the flow stress results due to the effect of the free surfaces.
Pierre Marcel Anicet Noah, Fabien Betene Ebanda, Louis-Max Ayina Ohandja, Ateba Atangana
Modeling and Numerical Simulation of Material Science, Volume 11, pp 19-33; doi:10.4236/mnsms.2021.111002

Abstract:
The objective of this paper is to investigate the relative variations of the constants of the thermal properties and the degree of crystallinity of the mixtures (PP/EPR)/Calcium carbonates elaborated with the Micro Bivis. We have strengthened the basic copolymer PP/EPR of a low level (5%) by three calcium carbonates models socal312, socal322v, Winnofil spm. We then subjected the different mixtures obtained, two cycles of a thermal loading under differential scanning calorimetry DSC. We finally focused on the thermal properties of isotactic polypropylene (TfP, TcP, ΔHfP, ΔHcP) and we calculated the degree of crystallinity of the mixtures. Reducing the energy cost of implementing mixtures is one of the objectives of this work. We quantified the relative variations of the above properties with those of the base copolymer. It shows that at a low loading rate of calcium carbonate, there is a decrease in the enthalpies of crystallization during the second exothermic cycle, with values that can reach 5.53 J/gPP for the basic copolymer PP/EPR. During the second endothermic cycle, there is an overall increase in isotactic polypropylene melting temperature values for all the blends as well as for the basic copolymer PP/EPR. There is evidence that calcium carbonates are useful for lowering the melting energy of isotactic polypropylene, even at a low loading rate for the majority. The number of endothermic cycles accentuates this phenomenon which is linked to the presence in our composites, of a so-called confined amorphous phase.
Matteo Villa, Jeffery W. Brooks, , Mark Ward
Modeling and Numerical Simulation of Material Science, Volume 10, pp 55-73; doi:10.4236/mnsms.2020.103004

Abstract:
The microstructural kinetics of β grain growth in the β field of a Ti-6Al-4V alloy was studied by a series of controlled heat treatments at constant temperature rates. Heating rates of 5°C/s, 50°C/s and 500°C/s were considered, stopping at different peak temperatures. The thickness evolution of martensitic needles and lamellar α laths, formed on cooling, was also investigated, by soaking the material above its β-transus temperature and cooling down at 5°C/s, 50°C/s, 100°C/s and 300°C/s till ambient temperature. Quantitative microstructural analyses were used to measure the particle dimensions. The β grain growth kinetics was reasonably well described by a modified Avrami equation. The thickness of α lamellae was a function of the cooling rate and the β grain dimension in which they nucleated. The martensite needle thickness was shown to be a function of the cooling rate to which the material was subjected.
Baha Tarchoun, Abderrazak El Ouafi, Ahmed Chebak
Modeling and Numerical Simulation of Material Science, Volume 10, pp 31-54; doi:10.4236/mnsms.2020.103003

Abstract:
Laser surface hardening is becoming one of the most successful heat treatment processes for improving wear and fatigue properties of steel parts. In this process, the heating system parameters and the material properties have important effects on the achieved hardened surface characteristics. The control of these variables using predictive modeling strategies leads to the desired surface properties without following the fastidious trial and error method. However, when the dimensions of the surface to be treated are larger than the cross section of the laser beam, various laser scanning patterns can be used. Due to their effects on the hardened surface properties, the attributes of the selected scanning patterns become significant variables in the process. This paper presents numerical and experimental investigations of four scanning patterns for laser surface hardening of AISI 4340 steel. The investigations are based on exhaustive modelling and simulation efforts carried out using a 3D finite element thermal analysis and structured experimental study according to Taguchi method. The temperature distribution and the hardness profile attributes are used to evaluate the effects of heating parameters and patterns design parameters on the hardened surface characteristics. This is very useful for integrating the scanning patterns’ features in an efficient predictive modeling approach. A structured experimental design combined to improved statistical analysis tools is used to assess the 3D model performance. The experiments are performed on a 3 kW Nd:Yag laser system. The modeling results exhibit a great agreement between the predicted and measured values for the hardened surface characteristics. The model evaluation reveals also its ability to provide not only accurate and robust predictions of the temperature distribution and the hardness profile as well an in-depth analysis of the effects of the process parameters.
Drissa Ouedraogo, Serge Wendsida Igo, Gaël Lassina Sawadogo, Abdoulaye Compaore, Belkacem Zeghmati, Xavier Chesneau
Modeling and Numerical Simulation of Material Science, Volume 10, pp 15-30; doi:10.4236/mnsms.2020.102002

Abstract:
In this work, a numerical study of heat transfers in a metallic pressure cooker isolated with kapok wool was carried out. This equipment works like a thermos, allowing finishing cooking meals only thanks to the heat stored at the beginning of cooking, which generates energy savings. Cooked meals are also kept hot for long hours. In our previous work, we have highlighted the performances of the pressure cooker when making common dishes in Burkina Faso. Also, the parameters (thickness and density) of the insulating matrix allowing having such performances as well as the influence of the climatic conditions on the pressure cooker operation were analyzed in detail in this present work. The numerical methodology is based on the nodal method and the transfer equations obtained by making an energy balance on each node have been discretized using an implicit scheme with finite differences and resolved by the Gauss algorithm. Numerical results validated experimentally show that the thickness of the kapok wool as well as its density play an important role in the pressure cooker operation. In addition, equipment performances are very little influenced by the weather conditions of the city of Ouagadougou (Burkina Faso).
Tomas De La Mora Ramírez, Isaías Hilerio Cruz, Marco Antonio Doñu Ruiz, Noé López Perrusquia, David García Bustos, Martín Flores Martínez
Modeling and Numerical Simulation of Material Science, Volume 10, pp 1-14; doi:10.4236/mnsms.2020.101001

Abstract:
Ultra-high molecular weight polyethylene (UHMWPE) has been used in orthopedics as one of the materials for artificial joints in knee, hip and spine prostheses, most of the implanted joints are designed so that the metal of the prosthesis is articulate against a polymeric material, however the main problems is the average life time of the UHMWPE due to wear, and the particles generated by the friction of the metal on the articulation of the polymer are the most common inducer of osteolysis, generating a loosening of the implant leading to an imminent failure resulting in the total replacement of the prosthesis. In this investigation a numerical model of abrasive wear was made using the classic Archard wear equation applied to dynamic simulation of finite element analysis (FEA) of the micro-abrasion test using a subroutine written in Fortran language linked to the finite element software to predict the rate of wear. The results of the numerical model were compared with tests of abrasive wear in the laboratory, obtaining a margin of error below 5%,concluding that the numerical model is feasible for the prediction of the rate of wear and could be applied in knowing the life cycle of joint prostheses or for the tribological analysis in industrial machinery or cutting tools. The wear coefficient (K) was obtained from the grinding tests depending on the depth of stroke of the crater, which was analyzed by 3D profilometry to obtain the wear rate and the wear constant.
Christopher E. Ozigagu, Anthony J. Duben
Modeling and Numerical Simulation of Material Science, Volume 09, pp 1-15; doi:10.4236/mnsms.2019.91001

Abstract:
The Soave-Redlich-Kwong (SRK-EOS) and Peng-Robinson (PR-EOS) equations of state are used often to describe the behavior of pure substances and mixtures despite difficulties in handling substances, like water, with high polarity and hydrogen bonding. They were employed in studying the binary vapor-liquid equilibria (VLE) of methane + methanol, monoethylene glycol (MEG), and triethylene glycol (TEG). These liquids are used to inhibit the formation of gas hydrates. The investigation focused on the conditions at which methane-water clathrates can form 283.89 K to 323.56 K and 5.01 MPa to 18.48 MPa. The pressure of methane in methanol is overestimated by a factor of two by either the SRK-EOS or the PR-EOS. In the methane + MEG system, the predicted pressures for both equations of state are generally less than experimental pressure except for the highest concentration of methane in MEG calculated by the SRK-EOS. In the methane + TEG system, the predictions of both models are close and trend similarly. Because of the comparative lack of extensive experimental methane + TEG data, the similarity of the methane + TEG computed results can be used as a basis for further study of this system experimentally.
Claude Lincourt, Jacques Lanteigne, Madhavarao Krishnadev, Carl Blais
Modeling and Numerical Simulation of Material Science, Volume 09, pp 17-28; doi:10.4236/mnsms.2019.92002

Abstract:
The intent of this paper is to propose an engineering approach to estimate the stress intensity factor of a micro crack emerging from an inclusion in relation with the morphology of the inclusion and its relative stiffness with the matrix. A micromechanical model, based on the FEA (finite element analysis) of the behavior of cracks initiated at micro structural features such as inclusions, has been developed using LEFM (Linear Elastic Fracture Mechanics) to predict the stress intensity factor of a micro crack emerging from an inclusion. Morphology of inclusions has important connotations in the development of the analysis. Stress intensity factor has been estimated from the FEA model for different crack geometries. Metallographic analysis of inclusions has been carried out to evaluate the typical inclusion geometry. It also suggests that micro cracks less than 1 μm behave differently than larger cracks.
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