Thermal transport in a highly porous metallic wire-woven bulk Kagome （WBK） is numerically and analytically modeled. Based on topology similarity and upon introducing an elongation parameter in thermal tortuosity, an...Thermal transport in a highly porous metallic wire-woven bulk Kagome （WBK） is numerically and analytically modeled. Based on topology similarity and upon introducing an elongation parameter in thermal tortuosity, an idealized Kagome with non-twisted struts is employed. Special focus is placed upon quanti- fying the effect of topological anisotropy of WBK upon its effective conductivity. It is demonstrated that the effective conductivity reduces linearly as the poros- ity increases, and the extent of the reduction is significantly dependent on the orientation of WBK. The governing physical mechanism of anisotropic thermal transport in WBK is found to be the anisotropic thermal tortuosity caused by the intrinsic anisotropic topology of WBK.展开更多
The paper deals with analytical models of the elastic energy gradient Wsq representing an energy barrier.The energy barrier is a surface integral of the elastic energy density Wq.The elastic energy density is induced ...The paper deals with analytical models of the elastic energy gradient Wsq representing an energy barrier.The energy barrier is a surface integral of the elastic energy density Wq.The elastic energy density is induced by thermal stresses acting in an isotropic spherical particle(q=p)with the radius R and in a cubic cell of an isotropic matrix(q=m).The spherical particle and the matrix are components of a multi-particle-matrix system representing a model system applicable to a real two-component material of a precipitation-matrix type.The multi-particle-matrix system thus consists of periodically distributed isotropic spherical particles and an isotropic infinite matrix.The infinite matrix is imaginarily divided into identical cubic cells with a central spherical particle in each of the cubic cells.The dimension d of the cubic cell then corresponds to an inter-particle distance.The parameters R,d along with the particle volume fraction v=v(R,d)as a function of R,d represent micro-structural characteristics of a real two-component material.The thermal stresses are investigated within the cubic cell,and accordingly are functions of the microstructural charac-teristics.The thermal stresses originate during a cooling pro-cess as a consequence of the difference am-ap in thermal expansion coefficients between the matrix and the particle,am and ap,respectively.The energy barrier Wsq is used for the determination of the thermal-stress induced strengthening aq.The strengthening represents resistance against com-pressive or tensile mechanical loading for am-ap〉0 or am-ap〈0.respectively.展开更多
基金supported by the National 111 Project of China(B06024)the National Basic Research Program of China(2011CB610305)
文摘Thermal transport in a highly porous metallic wire-woven bulk Kagome （WBK） is numerically and analytically modeled. Based on topology similarity and upon introducing an elongation parameter in thermal tortuosity, an idealized Kagome with non-twisted struts is employed. Special focus is placed upon quanti- fying the effect of topological anisotropy of WBK upon its effective conductivity. It is demonstrated that the effective conductivity reduces linearly as the poros- ity increases, and the extent of the reduction is significantly dependent on the orientation of WBK. The governing physical mechanism of anisotropic thermal transport in WBK is found to be the anisotropic thermal tortuosity caused by the intrinsic anisotropic topology of WBK.
基金supported by the Slovak Research and Development Agency under the contracts No.COST-0022-06,No.COST-0042-06,No.APVV-51-061505,No.APVV-0034-07,No.APVV-0171-06by the 6th FP EU NESPA+16 种基金by FP7-REGPOT-2007-3 DEMATEN 204953(05/08-04/11)by IMPROVING 229625by HANCOC-MNT.ERA-NET 01/09-12/11by NANOSMART Centre of Excellence(01/2007-12/2010)Slovak Academy of Sciencesby the Slovak Grant Agency VEGA(2/7197/27,2/7194/27,2/7195/27,1/4107/07)by iNTeg-Risk CP-IP 213345-2by European Structural Fund-Center of Excellence(Progressive Materials with Nano-and Submicron-Structure):ITMS NFP code 262200120019by COST Action 536by COST Action 538by OTKA Foundation(No.T043704,T043685,T 048593,T 63609)by HPRT-CT-2000-00037by EC5 Center of Excellence ICAI-CT-2000-70029by OTKA Postdoctoral Research Grant(D38478)by Swedish Research Council(No.621-2002-4299)by NSF-OTKA-MTA(No.MTA:96 OTKA:049953)by GVOP-3.2.1.-2004-04-0224/3.0by János Bolyai Research Grant.96/OTKA:049953,OTKA 63609
文摘The paper deals with analytical models of the elastic energy gradient Wsq representing an energy barrier.The energy barrier is a surface integral of the elastic energy density Wq.The elastic energy density is induced by thermal stresses acting in an isotropic spherical particle(q=p)with the radius R and in a cubic cell of an isotropic matrix(q=m).The spherical particle and the matrix are components of a multi-particle-matrix system representing a model system applicable to a real two-component material of a precipitation-matrix type.The multi-particle-matrix system thus consists of periodically distributed isotropic spherical particles and an isotropic infinite matrix.The infinite matrix is imaginarily divided into identical cubic cells with a central spherical particle in each of the cubic cells.The dimension d of the cubic cell then corresponds to an inter-particle distance.The parameters R,d along with the particle volume fraction v=v(R,d)as a function of R,d represent micro-structural characteristics of a real two-component material.The thermal stresses are investigated within the cubic cell,and accordingly are functions of the microstructural charac-teristics.The thermal stresses originate during a cooling pro-cess as a consequence of the difference am-ap in thermal expansion coefficients between the matrix and the particle,am and ap,respectively.The energy barrier Wsq is used for the determination of the thermal-stress induced strengthening aq.The strengthening represents resistance against com-pressive or tensile mechanical loading for am-ap〉0 or am-ap〈0.respectively.
