The Experts below are selected from a list of 342 Experts worldwide ranked by ideXlab platform
M Gupta - One of the best experts on this subject based on the ideXlab platform.
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synthesis and wear of al based free standing Functionally Gradient Materials effects of different reinforcements
Materials Science and Technology, 2004Co-Authors: Sharon Mui Ling Nai, M Gupta, C Y H LimAbstract:Abstract In the present study, three aluminium based Functionally Gradient Materials (FGMs), reinforced with different ceramic particulates (silicon carbide, aluminium oxide, and titanium carbide), were successfully synthesised using the innovative Gradient slurry disintegration and deposition (GSDD) technique. The results for Al/SiC and Al/Al2O3 revealed, in common, an increase in the weight percentage of reinforcement along the direction of deposition, to result in an increase in porosity and microhardness. However, for Al/TiC, the reverse trend was observed, with porosity and microhardness decreasing with increasing distance from the base of the ingot. The porosity levels for Al/TiC were also found to be significantly lower than those ofthe other two FGMs. Thermomechanical analysis of the FGMs showed thatthe average coefficient of thermal expansion of the high reinforcement end was reduced, as compared to the high aluminium end. Sliding wear test results also revealed that the high reinforcement end wa...
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synthesis and characterization of free standing bulk al sicp Functionally Gradient Materials effects of different stirrer geometries
Materials Research Bulletin, 2003Co-Authors: S M L Nai, M GuptaAbstract:Abstract This study addresses the effects of different stirrer geometries (two bladed, four bladed and circular shaped) on the synthesis of Al/SiCp Functionally Gradient Materials (FGMs) by an innovative process, termed here as the Gradient slurry disintegration and deposition process. The results of the three FGMs synthesized, revealed in common, an increase in the weight percentage of SiCp, porosity and microhardness along the direction of deposition. Thermomechanical analysis of the FGMs showed that the average coefficient of thermal expansion of the high SiCp end was reduced, as compared to that of the low SiCp end. Of the three stirrer geometries used, the two bladed stirrer yielded the most satisfactory results. An attempt is made in this study to establish the relationship between the processing parameter such as stirrer geometries, with the Gradient of SiC particulates realized in the ingots, microstructural evolution, CTE and microhardness results obtained.
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Synthesis of Al/SiC based Functionally Gradient Materials using technique of Gradient slurry disintegration and deposition: effect of stirring speed
Materials Science and Technology, 2003Co-Authors: Sharon Mui Ling Nai, M GuptaAbstract:In the present study, Al/SiC based Functionally Gradient Materials (FGMs) were successfully synthesised using the Gradient slurry disintegration and deposition technique. Gradients of SiC for the starting weight of 18% were successfully established by varying the stirring speed of the molten melt. The results revealed, in general, increases in the weight percentage and clustering tendency of SiC, porosity, and microhardness and a reduction in grain size, with increasing distance from the base of the FGM ingots. The results also showed that an increase in the stirring speed increases the homogeneity of SiC particulates distribution, thus resulting in a decrease in the Gradient of reinforcement along the deposition direction. Furthermore, an increase in the stirring speed decreases the number of clusters formed per unit area. An attempt has been made in the present work to establish the trend between processing parameters, such as stirring speed and the Gradient of SiC particulates realised in the ingots. © 2002 IoM Communications Ltd.
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influence of stirring speed on the synthesis of al sic based Functionally Gradient Materials
Composite Structures, 2002Co-Authors: Sharon Mui Ling Nai, M GuptaAbstract:Abstract In the present study, thick aluminum–silicon carbide based Functionally Gradient Materials, with starting weight of 18% SiC were successfully synthesized, using different stirring speeds and an innovative Gradient slurry disintegration and deposition technique. The results revealed, in common, an increase in: (a) the weight percentage of SiC particulates, (b) the clustering tendency of SiC, (c) porosity and (d) microhardness, and a reduction in grain size with increasing distance from the base of the Functionally Gradient material ingots. The results of X-ray diffraction studies indicated no evidence of interfacial reaction products. Furthermore, results revealed an increase in stirring speed increases the homogeneity of SiC particulates' distribution, thus resulting in a decrease in the average Gradient of reinforcement along the deposition direction. An attempt is made in this study to establish the trend between processing parameter such as stirring speed with the Gradient of SiC particulates realized in the ingots.
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synthesis of free standing one dimensional alsic based Functionally Gradient Materials using Gradient slurry disintegration and deposition
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2000Co-Authors: M Gupta, C Y LokeAbstract:Abstract In the present study, aluminum–silicon carbide based Functionally Gradient Materials were successfully synthesized using a new technique termed here as Gradient slurry disintegration and deposition process. Gradients of SiC were successfully established using this technique for the starting silicon carbide weight percentages ranging between 15–20%. The results were confirmed using microstructural characterization techniques and microhardness measurements. The results further revealed that an increase in the weight percentage of silicon carbide particulates along the deposition direction lead to a concurrent increase in porosity, degree of clustering and microhardness while the silicon carbide–aluminum interfacial integrity remained the same. An attempt is made to interrelate the processing methodology, microstructure and microhardness results obtained in the present study.
Yoshihiro Ochiai - One of the best experts on this subject based on the ideXlab platform.
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axial symmetric stationary heat conduction analysis of non homogeneous Materials by triple reciprocity boundary element method
Engineering Analysis With Boundary Elements, 2013Co-Authors: Yoshihiro Ochiai, V Sladek, J SladekAbstract:Abstract The heat conduction problems in homogeneous media can be easily solved by the boundary element method. The spatial variations of heat sources as well as material coefficients gives rise to domain integrals in integral formulations for solution of boundary value problems in Functionally Gradient Materials (FGM), since the fundamental solutions are not available for partial differential equations with variable coefficients, in general. In this paper, we present the development of the triple reciprocity method for solution of axial symmetric stationary heat conduction problems in continuously non-homogeneous media with eliminating the domain integrals. In this method, the spatial variations of domain “sources” are approximated by introducing new potential fields and using higher order fundamental solutions of the Laplace operator.
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two dimensional steady heat conduction in Functionally Gradient Materials by triple reciprocity boundary element method
Engineering Analysis With Boundary Elements, 2004Co-Authors: Yoshihiro OchiaiAbstract:Homogeneous heat conduction can be easily solved by means of the boundary element method. However, domain integrals are generally necessary to solve the heat conduction problem in the Functionally Gradient Materials. This paper shows that the two-dimensional heat conduction problem in the Functionally Gradient Materials can be solved approximately without a domain integral by the triple-reciprocity boundary element method. In this method, the distribution of domain effects is interpolated by integral equations. A new computer program is developed and applied to several problems.
Y Sugano - One of the best experts on this subject based on the ideXlab platform.
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a multicriterial material tailoring of a hollow cylinder in Functionally Gradient Materials scheme to global reduction of thermoelastic stresses
Computer Methods in Applied Mechanics and Engineering, 1996Co-Authors: K Tanaka, Y Sugano, H Watanabe, V F PoterasuAbstract:Abstract A method of macroscopic material tailoring is formulated in order to reduce globally the thermal stresses induced in the Functionally Gradient Materials (FGMs), with the help of the direct sensitivity analysis and the multiobjective optimization technique associated with the heat conduction/thermal stress analysis by means of incremental FEM. The spatial distribution of the volume fraction of phases is optimally determined under the following two constraints: The stress distribution is firstly, in the whole time-space domain, definitely inside an allowable band region, and then it approaches as close as possible to a given reference stress distribution inside the band. A hollow cylinder in a ceramics-metal FGM is tailored successfully when it is subjected to an asymmetric thermal boundary/initial condition.
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an improved solution to thermoelastic material design in Functionally Gradient Materials scheme to reduce thermal stresses
Computer Methods in Applied Mechanics and Engineering, 1993Co-Authors: K Tanaka, Y Tanaka, V F Poterasu, H Watanabe, Y SuganoAbstract:Abstract Thermoelastic material design in Functionally Gradient Materials (FGMs), which reduces the thermal stresses induced in the Materials by means of the direct sensitivity and optimization methods associated with the incremental thermoelastic/heat conduction finite element analysis, is generalized by allowing full spatial distribution in the volume fraction of the phases and non-linear dependence of the material parameters on the volume fraction. Numerical illustration of the theory is given for material design in a hollow circular cylinder subjected to asymmetric heating on the inner boundary.
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design of thermoelastic Materials using direct sensitivity and optimization methods reduction of thermal stresses in Functionally Gradient Materials
Computer Methods in Applied Mechanics and Engineering, 1993Co-Authors: K Tanaka, Y Tanaka, K Enomoto, V F Poterasu, Y SuganoAbstract:Abstract A methodology is presented for thermoelastic material design in Functionally Gradient Materials (FGMs) to reduce the thermoelastic thermal stresses induced under the would-be operational thermal boundary conditions. Direct sensitivity analysis and optimization techniques are employed to reach an optimal distribution of the volume fraction of the phases in the FGM. A numerical example is given to show the potential applicability of the proposed formulation.
Sharon Mui Ling Nai - One of the best experts on this subject based on the ideXlab platform.
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synthesis and wear of al based free standing Functionally Gradient Materials effects of different reinforcements
Materials Science and Technology, 2004Co-Authors: Sharon Mui Ling Nai, M Gupta, C Y H LimAbstract:Abstract In the present study, three aluminium based Functionally Gradient Materials (FGMs), reinforced with different ceramic particulates (silicon carbide, aluminium oxide, and titanium carbide), were successfully synthesised using the innovative Gradient slurry disintegration and deposition (GSDD) technique. The results for Al/SiC and Al/Al2O3 revealed, in common, an increase in the weight percentage of reinforcement along the direction of deposition, to result in an increase in porosity and microhardness. However, for Al/TiC, the reverse trend was observed, with porosity and microhardness decreasing with increasing distance from the base of the ingot. The porosity levels for Al/TiC were also found to be significantly lower than those ofthe other two FGMs. Thermomechanical analysis of the FGMs showed thatthe average coefficient of thermal expansion of the high reinforcement end was reduced, as compared to the high aluminium end. Sliding wear test results also revealed that the high reinforcement end wa...
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Synthesis of Al/SiC based Functionally Gradient Materials using technique of Gradient slurry disintegration and deposition: effect of stirring speed
Materials Science and Technology, 2003Co-Authors: Sharon Mui Ling Nai, M GuptaAbstract:In the present study, Al/SiC based Functionally Gradient Materials (FGMs) were successfully synthesised using the Gradient slurry disintegration and deposition technique. Gradients of SiC for the starting weight of 18% were successfully established by varying the stirring speed of the molten melt. The results revealed, in general, increases in the weight percentage and clustering tendency of SiC, porosity, and microhardness and a reduction in grain size, with increasing distance from the base of the FGM ingots. The results also showed that an increase in the stirring speed increases the homogeneity of SiC particulates distribution, thus resulting in a decrease in the Gradient of reinforcement along the deposition direction. Furthermore, an increase in the stirring speed decreases the number of clusters formed per unit area. An attempt has been made in the present work to establish the trend between processing parameters, such as stirring speed and the Gradient of SiC particulates realised in the ingots. © 2002 IoM Communications Ltd.
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influence of stirring speed on the synthesis of al sic based Functionally Gradient Materials
Composite Structures, 2002Co-Authors: Sharon Mui Ling Nai, M GuptaAbstract:Abstract In the present study, thick aluminum–silicon carbide based Functionally Gradient Materials, with starting weight of 18% SiC were successfully synthesized, using different stirring speeds and an innovative Gradient slurry disintegration and deposition technique. The results revealed, in common, an increase in: (a) the weight percentage of SiC particulates, (b) the clustering tendency of SiC, (c) porosity and (d) microhardness, and a reduction in grain size with increasing distance from the base of the Functionally Gradient material ingots. The results of X-ray diffraction studies indicated no evidence of interfacial reaction products. Furthermore, results revealed an increase in stirring speed increases the homogeneity of SiC particulates' distribution, thus resulting in a decrease in the average Gradient of reinforcement along the deposition direction. An attempt is made in this study to establish the trend between processing parameter such as stirring speed with the Gradient of SiC particulates realized in the ingots.
K Tanaka - One of the best experts on this subject based on the ideXlab platform.
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a multicriterial material tailoring of a hollow cylinder in Functionally Gradient Materials scheme to global reduction of thermoelastic stresses
Computer Methods in Applied Mechanics and Engineering, 1996Co-Authors: K Tanaka, Y Sugano, H Watanabe, V F PoterasuAbstract:Abstract A method of macroscopic material tailoring is formulated in order to reduce globally the thermal stresses induced in the Functionally Gradient Materials (FGMs), with the help of the direct sensitivity analysis and the multiobjective optimization technique associated with the heat conduction/thermal stress analysis by means of incremental FEM. The spatial distribution of the volume fraction of phases is optimally determined under the following two constraints: The stress distribution is firstly, in the whole time-space domain, definitely inside an allowable band region, and then it approaches as close as possible to a given reference stress distribution inside the band. A hollow cylinder in a ceramics-metal FGM is tailored successfully when it is subjected to an asymmetric thermal boundary/initial condition.
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an improved solution to thermoelastic material design in Functionally Gradient Materials scheme to reduce thermal stresses
Computer Methods in Applied Mechanics and Engineering, 1993Co-Authors: K Tanaka, Y Tanaka, V F Poterasu, H Watanabe, Y SuganoAbstract:Abstract Thermoelastic material design in Functionally Gradient Materials (FGMs), which reduces the thermal stresses induced in the Materials by means of the direct sensitivity and optimization methods associated with the incremental thermoelastic/heat conduction finite element analysis, is generalized by allowing full spatial distribution in the volume fraction of the phases and non-linear dependence of the material parameters on the volume fraction. Numerical illustration of the theory is given for material design in a hollow circular cylinder subjected to asymmetric heating on the inner boundary.
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design of thermoelastic Materials using direct sensitivity and optimization methods reduction of thermal stresses in Functionally Gradient Materials
Computer Methods in Applied Mechanics and Engineering, 1993Co-Authors: K Tanaka, Y Tanaka, K Enomoto, V F Poterasu, Y SuganoAbstract:Abstract A methodology is presented for thermoelastic material design in Functionally Gradient Materials (FGMs) to reduce the thermoelastic thermal stresses induced under the would-be operational thermal boundary conditions. Direct sensitivity analysis and optimization techniques are employed to reach an optimal distribution of the volume fraction of the phases in the FGM. A numerical example is given to show the potential applicability of the proposed formulation.
