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National Institute for Materials Science

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[Functionally Graded Materials VII (FGM2002) (pp.601-829)](https://mdr.nims.go.jp/datasets/38fe6fc7-2cd8-463c-b993-1bfca654b8d7)

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Sheet1 BookTitle_j BookTitle_e Volume/Issue Issueddate Page Title_j Title_e AuthorList_j AuthorList_e Abstract Language Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 601-606 熱機械荷重下での傾斜機能被覆及び均質基板間の界面亀裂 An Interface Crack between a Functionally Graded Coating and a Homogeneous Substrate under Thermo-mechanical Loading Sami El-Borgi, Fazil Erdogan, Fafa Ben Hatira Sami El-Borgi, Fazil Erdogan, Fafa Ben Hatira  In this paper, we consider the problem of a functionally graded coating bonded to a homogeneous substrate with a partially insulated interface crack subject to both thermal and mechanical loading. The equations of heat conduction and plane elasticity are converted analytically into singular integral equations which are solved numerically to yield the temperature and the displacement fields in the medium as well as the stress intensity factors. The Finite Element Method was also used to model the crack problem and to compute the crack-tip stress intensity factors using higher order nonhomogeneous elements. The main objective of the paper is to study the effect of the material nonhomogeneity parameters on the crack tip stress intensity factors for further understanding the behavior of graded materials. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 607-612 熱荷重下の傾斜機能材料における二亀裂伝搬問題 Two-Cracks Propagation Problem in A Functionally Graded Material Plate under Thermal Loads 野田直剛, Masayuki Ishihara, Noriyuki Yamamoto, Takao Fujimoto Naotake Noda, Masayuki Ishihara, Noriyuki Yamamoto, Takao Fujimoto  This paper studies the crack propagation path in a ceramic/metal functionally graded material plate (FGP) with two end cracks under a transient temperature field. When the FGP is subjected to severe thermal conditions, a single crack or multiple cracks often occur on the ceramic surface at cooling process. The crack may propagate along thickness direction or parallel direction to the surface. The crack propagation paths are influenced by heating temperature, a compositional profile of the FGP, interaction among multiple cracks, and so on. The crack propagation path is calculated as a linear quasi-static thermoelastic problem for a plane strain state by use of a finite element method. The crack paths are roughly classified into two cases; one is straight propagation path and other is curved path. These phenomena are discussed for two-cracks propagation. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 613-618 均一温度変化下での界面エッジクラックをもつ傾斜機能材料のエネルギー解放率 Energy Release Rate of Functionally Graded Materials with Interface Edge-Cracks under Uniform Temperature Change Peng-Cheng Thai, 橋田俊之, Qing-Jie Zhang Peng-Cheng Thai, Toshiyuki Hashida, Qing-Jie Zhang  Elastic analysis has been used to estimate the driving force for interface edge-crack growth in TBC system with layered FGM coat under an uniform change in temperature. According to some simplified assumptions, closed-form solutions of thermal stresses are obtained and the energy release rates are estimated. For the case of layered FGM, the energy release rate is a function of the geometry parameters of the layers and thermo-mechanical properties of each layer. In addition, the FGM coating system is designed for the purpose of minimizing the energy release rate. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 619-622 遠心鋳造によるアルミニウム基In-situ FGMの靭性／脆性のフラクタル識別 Fractal Discrimination of toughness/fragileness on In-situ FGM of Aluminum Base by Centrifugal Casting Zili Xu Zili Xu  The fracture shapes are different on the various section spots along the gradient orientation of FGM. Leading the fracture analysis into the field of fractal, determining and calculating the fractal parameter, the variation of toughness and brittleness in sections of materials could be discriminated. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 623-627 傾斜機能圧電材料のモード３亀裂の解析 Analysis of a Mode III Crack in a Functionally Gradient Piezoelectric Material Z.Zhong, D.W.Shu, B.Jin Z.Zhong, D.W.Shu, B.Jin  In this paper we studied a finite crack in an infinite medium made of a functionally gradient piezoelectric material subjected to antiplane shear and inplane electric field. The material properties, including the elastic shear modulus, the piezoelectric modulus and the dielectric modulus are assumed to vary exponentially with spatial position. By means of Fourier transformation, the governing equations of the problem are firstly reduced to two pairs of dual integral equations and then to a Fredholm integral equation of second kind. The electroelastic fields are completely determined and the field intensity factors can be defined. It is found that the stress and the electric displacement have the inverse square-root singularity at the crack tip as that of homogeneous piezoelectric materials, and the stress intensity factor and the electric displacement intensity factor increase with the increase of the material gradient constant of functionally gradient piezoelectric materials. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 629-634  T*亀裂を基にした傾斜機能材料の亀裂速度の評価 Estimate of Crack Speed in Functionally Graded Material Based on T*Crack 中垣通彦, Huajian Chang, KenichiYamazaki Michihiko Nakagaki, Huajian Chang, KenichiYamazaki  A theoretical/computational methodology for the analysis of the FGM is introduced, and its application is made to the problem of a dynamically propagating crack running transversely in the FGM, where the intensity of the estimated crack-tip severity is managed to keep in valance with the graded material toughness in the FGM during the propagation. To detect the crack-tip severity, an integral fracture parameter, T*, is used. The crack is propagated so that the value of T* is equated to the prescribed varying critical values of T*. Emphasis is placed on the use of a fuzzy inference algorithm to control the crack speed deduced from a few T* values immediately preceding the current crack position. As to describing the constitutive law for the FGM, spherical particles of arbitrary size in mesoscale are supposed to be randomly dispersed in the matrix medium. By assuming that the volume fraction of the inclusion is continuously varied, the grading is modeled. For modeling the constitutive law for the FGM composite media of thermo-elastoplasticity, a closed form SCC-LRM constitutive model describing the nonlinear material mechanics of the particle-dispersed medium is used. The model is based on the self-consistent scheme and uses Eshelby's equivalent inclusion method. Unprecedented analytical results of crack speed of a crack running transversely in the FGM plate are shown. In some cases of material grading, apparent crack arresting is observed as the crack runs into the metal rich area of the FGM. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 635-640 任意分布特性の傾斜機能材料の表面亀裂 Surface Cracking of Functionally Graded Materials with Arbitrarily Distributed Properties B.L.Wang, Y-W.Mai, X.H.Zhang, J.C.Han B.L.Wang, Y-W.Mai, X.H.Zhang, J.C.Han  Functionally Graded Materials (FGMs) have been developed as super-resistant materials for propulsion systems and airframes of space-planes to reduce thermal stresses and increase protection from heat. Generally, failures of functionally graded materials involve two types of cracks, namely a surface crack propagating perpendicular to and an embedded crack along the boundary. In this paper, a functionally graded material strip containing a surface crack perpendicular to the boundary is considered. The graded region is treated as a large number of single layers, with each layer being homogeneous material. The problem is reduced to an integral equation and is solved numerically. Unlike most of existing researches, which considered only certain assumed material property distributions, the analytical model developed in this work can be used to study functionally graded materials with arbitrarily varied material properties. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 641-644 セラミック／金属 FGMの衝撃特性解析 Impact Characteristic Analysis of Ceramic/Metal FGM Li-Sheng Liu, Qing-Jie Zhang, Peng-Cheng Zhai, Chang-Chun Zhu Li-Sheng Liu, Qing-Jie Zhang, Peng-Cheng Thai, Chang-Chun Zhu  The ceramic composite armor has been lucubrated in the past 40 years. Ceramic can provide the same protection as metal, but it has lighter weight than metal. Ceramic has excellent ability of resisting kinetic energy projectile, because it can transfer energy to a large range by its fragmented cone and has higher ability of eroding the projectile than metal. But the researches indicated the full potential of the ceramic hard face has not been achieved because the significant interface between ceramic and metal has the unfavorable impedance effects and would induce tensile failure. FGM is a new type composite with continuous transition from ceramic to metal; it has no significant discrete materials interfaces between ceramic and metal. This paper deals with the impact response of Ceramic/FGM/Metal armor by numerical and theoretical methods. Firstly, the ability of TiB2/FGM/Metal armor resisting KE projectile is analyzed by Dytran FEM program. The comparison between TiB2/Metal armor and TiB2/FGM/Metal armor had been done; the results indicated that two main reasons result in the FGM armor is stronger than TiB2/Metal armor. One is FGM armor can make the best of the ceramic's hard face because of its continuous transition between ceramic and metal; another is the FGM armor can transfer energy to larger region than the ceramic/metal armor. Then, the penetration depth, residual velocity and mass of projectile have been analyzed by Dytran as FGM armor is attacked by 1000m/s projectile, three relations are attained: (1) the relation between the penetration depth and FGM's thickness; (2) the relation between the residual velocity and FGM's thickness; (3) the relation between the residual mass and FGM's thickness. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 651-658 傾斜機能被覆の動的破壊 Dynamic Fracture of a Functionally Graded Coating Gan-Yun Huang, Yue-Sheng Wang Gan-Yun Huang, Yue-Sheng Wang  A new multi-layered model has been developed for dynamic fracture analysis of functionally graded materials (FGMs) whose properties may vary arbitrarily in its thickness direction. In this model, the FGM is divided into several sub-layers. The properties of the material are assumed to vary linearly along its thickness direction in each layer and continuous at the interfaces. The problem of a crack subjected to a harmonic anti-plane shear load in a graded coating bonded to a homogeneous half plane is then investigated by using the new model. Employment of the transfer matrix method and Fourier integral transform technique reduces the problem to a Cauchy type singular integral equation which is solved numerically. Dynamic stress intensity factors (DSIFs) are presented. Results show that the new model is very efficient. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 645-650 傾斜薄膜／基板界面へき開破壊の凝集モデル Cohesive Model for Thin Graded Film/Substrate Interfacial Cleavage Fracture Ran Li, Shouwen Yu Ran Li, Shouwen Yu  Film/substrate structure is a basic structure widely used in microelectronic and materials science and technology. The residual stress in the film induced by mechanical and thermal mismatch in the manufacture is an important cause of initialization and extension of interface crack. The modified three-parameter ((gamma)0, (sigma)/(sigma)y,t) cohesive model was used to investigate the cleavage fracture under plastic atmosphere, the stress distribution in crack tip, the shape and physiognomy of crack tip and the influence of the parameter on fracture process. The model was also used to discuss the whole process of the initialization and extension of interface crack between uniform and functional graded metal thin film and ceramic substrate under residual stresses. This model was also used to analyze the interfacial crack extension between enhanced functional graded thin film and substrate. The results were compared with that of the uniform films. The characteristic of the interfacial crack in graded film/substrate was emphasized. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 659-664  傾斜機能材料層をもつ被覆構造中の残留応力のFEMシミュレーション及び最適化 FEM Simulations and Optimization about Residual Stresses in Coating Structures with Functionally Graded Materials Layer Chenguang Huang, Siying Chen, Zhuping Duan Chenguang Huang, Siying Chen, Zhuping Duan  An elasto-plastic finite element method is developed to predict the residual stresses of thermal spraying coatings with functionally graded material layer. In numerical simulations, temperature sensitivity of various material constants is included and mixture law is used to depict the constitutive behaviors of FGM layer. The optimized distribution form of the volume fractions of constituents in FGM is obtained by the first order optimization method in the AL2O3-Ni system. At the same time, Effects of geometry and materials behaviors on the optimization result are also investigated numerically. When the length of specimen, the width of FGM layer and thermal expanding coefficient of the substrate material increase, the optimized distribution parameter p decreases obviously. It is found that the optimization of the constituent contents in FGM reduces the magnitude of residual stresses to a large degree and makes the maximum residual stresses to shun the weakest part of the coating structure. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 665-670 傾斜機能材料の中空円筒の過渡及び残留応力 Transient and Residual Stresses in a Hollow Cylinder of Functionally Graded Materials Chunhong Chen, 淡路英夫 Chunhong Chen, Hideo Awaji  One-dimensional transient and residual stress fields in a hollow cylinder of functionally graded materials (FGMs) for two models of ceramic-metal systems are studied subjected to severe thermal shock. It is clear that residual stresses in FGMs arise primarily from spatial variations in the thermal expansion coefficient, but can be significantly modulated by the Young's modulus gradient. Analytical results of the thermal stress required to reduce the transient stress and residual stress in the FGM provide a means of appropriate microstructure design for FGMs to select FGM constituents and spatial variation in material properties. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 671-675 セラミック／金属傾斜円筒モデルの熱伝達及び熱応力解析 Heat Transfer and Thermal Stress Analysis of Ceramic/Metal Gradient Cylinder Model Jinsheng Xiao, Feng Qin, Jie Liu, Zhigang Zhan Jinsheng Xiao, Feng Qin, Jie Liu, Zhigang Zhan  The multi-layer ceramic/metal gradient cylinder model is useful for many engineering cases. The heat transfer in the cylinder with coating inside is calculated by analytical method and finite element method. The thermal stress in a single layer gradient cylinder suffering even temperature and a multi-layer gradient cylinder with coating inside suffering uneven temperature is respectively analyzed by finite difference method, finite element method and zoned-uniform method. The results show that finite element method agrees well with analytical method in the heat transfer analysis; finite difference method, finite element method and zoned-uniform method agree well with each other in the thermal stress analysis. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 677-680 セラミック傾斜機能材料中の熱残留応力の有限要素解析：残留低減のための界面最適化 Finite Element Analysis of Thermal Residual Stress in Ceramic Functional Graded Material: Interface Optimization for Residual Reduction Likun Hou, Wei Pan, Reigang Wang, Dan Xie Likun Hou, Wei Pan, Reigang Wang, Dan Xie  An elastic finite element method numerical model developed for predicting thermal residual stresses in graded ceramic-ceramic materials has been applied to determine interface conditions favorable for achieving residual stress reductions. Using the Si3N4-BN FGM composite sintered in a heat-pressed sintering furnace as a model system, and for fixed specimen geometry, a study was performed to investigate the effects of different composition profiles on stress distributions established during the uniform cooling from an assumed sintering temperature. For each interface condition, the magnitude of specific stress components important for controlling interface failure are compared with each other. For the geometry and sintering condition, stress was reduced by nonlinear composition profiles.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 681-686 セラミック／金属傾斜機能材料の複合円筒のための熱弾塑性限界解析及び最適設計 Thermal Elastic-Plastic Limit Analysis and Optimal Design for Composite Cylinders of Ceramic/Metal Functionally Graded Materials Jing Huang, Yunbing Lu, Chengwu Shen Jing Huang, Yunbing Lu, Chengwu Shen  In this paper, based on the theoretical analysis of steady-state heat conduction and a plastic limit state, the analytical expressions are presented for both the steady-state temperature fields and thermal elastic-plastic stresses in cylinders of ceramic/metal functionally graded materials (FGM) through the thickness of the cylinder. Based on the theoretical analysis of the limit state defined in this paper, the optimal design for the parameters of the FGM design is carried out. Analytical solutions of the steady-state temperature field and thermal elastic-plastic stresses are discussed for the ZrO2/Ti-6Al-4V system.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 687-692 熱衝撃下の傾斜機能材料の計算微視力学解析 Computational Micromechanics Analysis of the Functionally Graded Materials under Thermal Shock Loading Shuyong Yang, Qingjie Zhang, Pengcheng Zhai Shuyong Yang, Qingjie Zhang, Pengcheng Thai  Researchers have developed various modeling techniques to study the response problems of FGMs under the thermal shock loading. In these traditional modeling methods, each interlayer of FGMs is usually simplified into an isotropic layer. Under this simplification, almost all the characteristics of FGMs in micro scale are neglected and it is impossible to obtain the responses in micro scale. However, it is well known that the responses in micro scale, especially for thermal stresses, are important to the explanation of the initiation and propagation of the micro damage. For the purpose of the design and application of FGMs, microscopic analysis is requisite. In this paper, CMM is applied to analyze the responses of FGMs under the thermal shock loading in micro scale. Essentially, this method is a FE analysis method based on the real microstructure of FGMs. The geometry models used in this method come from SEM images of the corresponding FGM samples. A simple and efficient method is applied to generate FE grids from geometry models. The generated models can reflect the real microstructure of FGMs in detail. Finally, FE grids are employed to analyze the responses of FGMs under the thermal shock loading and the thermo- mechanical responses in micro scale are obtained. Moreover, the problem is also analyzed with the traditional method. From the numerical results and discussions, conclusions are summarized as following: (1) CMM is efficient for the microscopic response analysis of FGMs under the thermal shock loading; (2) the temperature field calculated by CMM is basically consistent with the one calculated with the traditional method; (3) the stress field calculated with CMM is very complex and quite different from the stress field calculated with the traditional method.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 693-698 熱衝撃下での多層中FGM板の応力解析 Stress Analysis in Multilayered FGM Plates under Thermal Shock 金剛, 西川直宏, 本多沢雄, 淡路英夫 G.Jin, T.Nishikawa, S.Honda, H.Awaji  In this study, one-dimensional calculation was employed to evaluate the steady-state and transient temperature/stress distributions in a multilayered functionally graded ceramic-metal composite materials. The residual thermal stress raised from fabrication process because of the macroscopic variation of constituent across the thickness was also evaluated. The alumina/nickel FGM disks were fabricated using a powder stacking method and a pulse electric current sintering technique. The thermal shock tests on the fabricated FGM disks were performed and the stress distributions in the FGM plates under thermal shock were calculated using a critical temperature difference where cracks appeared on the ceramic surface. Then the thermal shock properties of FGM plates were evaluated under the consideration of both the thermal stress and the residual thermal stress distribution. It was indicated that the thermal shock properties of the multilayered alumina-nickel FGM plate were strongly influenced by the residual thermal stress distribution on the alumina surface.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 699-702 傾斜機能材料の熱応力研究 Thermal Stress Research on the Functionally Gradient Material Shuhua Li, Shen Wang, Jinnan Chen, Runze Yang Shuhua Li, Shen Wang, Jinnan Chen, Runze Yang  The thermal stress analysis for functional gradient material by using analytical method and finite element method were introduced in this paper. The research work for thermal stress analysis of the functional gradient material was reviewed. The developing trend in thermal stress of functional gradient material was discussed.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 703-706 熱応力緩和を伴う軸対称形状FGMのための傾斜形成設計の解析 Analysis of Gradient Forming Design for FGM of Axisymmetrical Geometries with Thermal Stress Relaxation Zili Xu Zili Xu  This paper presents the linear model of physics values, which makes the calculation of thermal stress of FGM much more simplified., and the practical fabrication of FGM much more feasible. Further, the ideas of gradient forming design of FGM of axisymmetrical geometries are put forward through analyses of the steady thermal stress, which will be of sound significance to the design for FGM.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 707-711 レーザ転換硬化プロセスにおけるレーザ処理領域の深さ評価の数値モデル開発と実験的検証 Development and Experimental Validation of a Numerical Thermal Model for the Evaluation of the Depth of Laser Treated Zone in the Laser Transformation Hardening Process Noe Cheung, Maria Aparecida Pinto, Maria C.F.Lerardi, Amauri Garcia Noe Cheung, Maria Aparecida Pinto, Maria C.F.Lerardi, Amauri Garcia  The aim of this work is to develop a mathematical model to predict the depth of laser treated zone in the LTH process. The Fourier equation of heat conduction was solved by using the Finite Difference Method in cylindrical coordinates in order to study the temperature distribution produced in a workpiece and hence to obtain the depth to which hardening occurs. The theoretical simulations were compared with results produced experimentally by a CO2 laser operating in continuous wave, showing good agreement.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 713-718 微視的遺伝アルゴリズムによる熱負荷下でのFGMコーティングの物質組成最適化 Optimization of Material Composition of FGM Coating under Thermal Loading by Micro Genetic Algorithms Gang Chen,Peng-Cheng Zhai,Qing-Jie Zhang Gang Chen,Peng-Cheng Zhai,Qing-Jie Zhang  The present paper studies the optimization problem of material composition distribution for functionally graded materials (FGMs) coating system subjected to thermal loading. The each interlayer of FGMs coating and substrate materials are assumed to be thermo-elastic, and the material parameters of each interlayer are gained by micromechanics method. Optimizing the thermal stress distribution and minimizing the thermal stress are carried out by micro Genetic Algorithms. Optimization results of composition distribution of FGMs are gained. The results show that the micro Genetic Algorithms is an efficient method for the optimization problem of material composition distribution for FGMs.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 719-724 均一分布の径方向圧縮を受けた機能性材料の円板の軸対称性座屈後 Axisymmetric Post-Buckling of a Functionally Graded Circular Plate Subjected to Uniformly Distributed Radial Compression L. S. Ma, T. J. Wang L. S. Ma, T. J. Wang  Based On the classical nonlinear plate theory, axisymmetric post-buckling behavior of a functionally graded circular plate is investigated under uniformly distributed radial compression. The governing equations are derived for the plate, and then a shooting method is employed to numerically solve the resulting differential equations. It is assumed that the thermal and mechanical properties of the functionally graded material vary varying continuously through the thickness of the plate, and follow a simple power law distribution of the volume fraction of the constituents. Axisymmetric post-buckling equilibrium paths for both clamped and simply supported plates are obtained. Also, variations of the central bending moments in the plate with the applied load are obtained after buckling of the plate. Furthermore, effects of the gradients of material properties and boundary conditions on the critical buckling load and post-buckling behavior of the functionally graded plates with different boundary conditions are discussed. Numerical results show that the post-buckling behavior of a functionally graded plate is different from that of homogenous plate, the gradients of material properties and the boundary conditions play important roles in analyzing post-buckling behavior of the functionally graded materials plates.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 725-729 FGM熱弾性構造を最適化するための随伴方程式の利用 Using the Adjoint Equation Method to Optimize FGM Thermoelastic Structures                                                                 Djaffar Boussaa, Lotfi Jaballah Djaffar Boussaa, Lotfi Jaballah  The paper is concerned with the problem of optimizing the composition profile of thermoelastic structures made of functionally graded materials using gradient-based approaches. The problem is posed as an optimal control problem and the derivative of its objective functional is derived using the adjoint equations. The derivative information is made use of to optimize the composition profile of the functionally graded interlayer of a three-1ayer cylinder.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 731-736 傾斜機能要素の弾性と塑性の解析 Elastic and Plastic Analyses of Functionally Graded Elements                                                                       Lin Ma, Xi-Qiao Feng, Ke-Wei Gao,  Shou-Wen Yu Lin Ma, Xi-Qiao Feng, Ke-Wei Gao,  Shou-Wen Yu  In this paper, some functionally gradient elements of extensive engineering interest including plates, beams, cylinders and thick-walled tubes are theoretically investigated. First, some elastic analytical solutions are derived for such components made of functionally graded materials (FGMs) under different loadings, and the effective elastic properties are formulated in explicit expressions. These solutions are compared to the conventional composite models in micromechanics, and thereby some interesting conclusions are obtained. Then, the above elements are investigated based on the theory of plasticity. The results are useful for design and analysis of FGMs-based structures and for optimization of FGMs.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 737-742 解離界面を持つ粒子分散複合体の異方性評価 Assessment on Anisotropic Properties of Particle-Dispersed Composites with Debonded Interface Huajian Chang, 中垣通彦 Huajian Chang, Michihiko Nakagaki  A theoretical procedure to analyze the overall properties of the particle-dispersed composite material is proposed. The localized behavior of the debonded interface between the matrix and the interface is modeled based on the micromechanical method. The effects of interfacial delamination on the strain field inside the particles are represented by a modified Eshelby tensor. Furthermore, the interfacial delamination may cause an additional strain at the interface. This effect is taken into account by introducing damage effected tensors. With the use of these tensors, a constitutive model is obtained, which is on the bases of equivalent inclusion method, and of a self-consistent compliance scheme. If the particles are not randomly dispersed, when damage occurs at the interface under uniaxial tension, the composite will behave anisotropic properties. This effect is also taken into consideration in the meso- and macro level. The numerical calculations are carried out. The results in some typical conditions of interface are discussed. It is concluded that the interfacial delamination has a dramatically detrimental effect on the overall properties of the composite materials. It is also revealed that the composite material as a whole will be orthorhombic due to the interfacial damage, when the particles are regularly arranged.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 743-748 傾斜機能材料の球状に等方性の中空球の変形について On Deformations of a Spherically Isotropic Hollow Sphere of a Functionally Graded Material W. Q. Chen, Z. G. Bian, H. J. Ding W. Q. Chen, Z. G. Bian, H. J. Ding  By introducing three displacement functions and two stress functions, two independent state equations with variable coefficients are derived from the three-dimensional equilibrium equations of a radially inhomogeneous spherically isotropic elastic medium. By virtue of the laminate approximation theory, the state equations are then transformed to the ones with constant variables, of which the solutions can be easily obtained. The continuity conditions at each fictitious interface then lead to linear algebraic equations about the state variables at the inner and outer spherical surfaces only. Numerical example of a functionally graded hollow sphere subjected to external loading is considered and the effect of the material gradient index(or the inhomogeneity parameter) is discussed.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 749-752 待避線における傾斜した機械的性質の形成 Formation of Graded Mechanical Properties in Turnouts Changhong Li,  Beizhong Wang Changhong Li,  Beizhong Wang  An alloy steel with graded mechanical properties suitable to turnouts was designed and made. In the process of forming graded mechanical properties, a graded varying section structure was adopted, which realized continuously varying transition with different ratio between strength and toughness under pressure. Graded distribution of strength and toughness in turnouts solved the contradiction between the need of high strength for long life and the need of good toughness for safe use. The largest tensile strength locating at top part of turnouts is up to 1512 MPa accompanying notch toughness of 120J/cm2. The greatest notch toughness lying in lower part of turnouts is 338 J/cm2 accompanying tensile strength of 895 MPa.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 753-757 ツインスクリュー押出機における粒子軌跡のシミュレーションと統計解析 Simulation of Particle Trajectories and Statistical Analysis in Twin-Screw Extruders Dongdong Hu, Jinnan Chen Dongdong Hu, Jinnan Chen  Three-dimensional isothermal flows in the intermeshing co- and counter-rotating twin-screw extruders are simulated respectively using the finite element package POLYFLOW. On the basis of the calculated flow field, particle trajectories are visualized and the mixing status is statistically analyzed in these two types of machines.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 759-762 壁滑りがあるツインスクリュー押出の数値シミュレーション Numerical Simulation of Twin-Screw Extrusion with Wall Slip Dongdong Hu, Jinnan Chen Dongdong Hu, Jinnan Chen  Three-dimensional isothermal twin-screw extrusion with wall slip is simulated using the fluid dynamic analysis package POLYFLOW. Profiles of velocity contours in the screw channel and shear rate distributions in the intermeshing region are presented. Curves of axial pressure difference, average shear rate and dispersive mixing index vs. the slip coefficient are plotted and discussed. Comparisons are also made between the wall-slip conditions and the non-slip condition.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 763-767 セラミック/金属の勾配熱障壁コーティングの設計ソフトウエアの開発 Development of Ceramic/Metal Gradient Thermal Barrier Coating Design Software Jinsheng Xiao, Chunzhi Hu, Dongzhou Cui, Yunhua Guo Jinsheng Xiao, Chunzhi Hu, Dongzhou Cui, Yunhua Guo  The Ceramic/metal gradient thermal barrier Coating Design Software(CCDS) is developed for analyzing the heat transfer and the thermal stress in the coatings, and for designing the optimal coating schemes. The CCDS is developed according to software engineering methodology with Borland C++ Builder 5.0 and has user-friendly interface. It is composed of three functional modules: preprocess module, analysis module and post process module. Initial data are input in the preprocess module, calculation of the temperature and thermal stress is carried out in the analysis module, and visualization is realized by the post process module. Calculation is carried out by analytical method, finite difference method and finite element method. In addition, the CCDS is enhanced by attaching an optimization design module which completes optimization design for ceramic/metal gradient thermal barrier coatings by ANSYS Parameter Design Language (APDL) or genetic algorithm, and an expert system module which may propose schemes and suggestions for coating design. The CCDS is useful for the design of ceramic/metal gradient thermal barrier coating.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 769-776 FGM高次理論の効率的な再定式化 Efficient Reformulation of the Higher-Order Theory for FGMs Yogesh Bansal, Yi Zhong, Marek-Jerzy Pindera Yogesh Bansal, Yi Zhong, Marek-Jerzy Pindera  The majority of techniques employed for the analysis of functionally graded materials (FGMs) use the so-called uncoupled approach which is based on homogenized material property variations and thus ignores the effect of microstructural gradation. The higher-order theory for functionally graded materials (HOTFGM) is a coupled approach which explicitly takes the effect of microstructural gradation, and thus the local-global interaction of the spatially variable inclusion phase(s), into account. Despite its demonstrated utility, however, the original formulation of HOTFGM is computationally intensive. Herein, an efficient reformulation of HOTFGM is presented based on the local-global conductivity and stiffness matrix formulation. In this approach, surface-averaged quantities are the primary variables which replace volume-averaged quantities employed in the original formulation. The reformulation decreases the size of the global conductivity and stiffness matrices by approximately sixty percent, facilitating modeling of realistic microstructures. The presented results illustrate the efficiency of the reformulation and its advantages in analyzing FGMs.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 777-783 一般化傾斜機能材料構造の不均一な構造理論 The Heterogeneous Constitutive Theory of the Generalized Functionally Graded Materials Structure Yong Li, Jian Song, Zhimin Zhang Yong Li, Jian Song, Zhimin Zhang  In those preceding analyses of FGM structure, most of the researches emphasized the significance of the meso-structure and ignored the macro-structure. There are certain limitations regarding grads essence, which fully embodies the combination of the macroscopic and meso-scopic respects of structure in their researches. In addition, the existing mechanical theory has not been employed to systemize their theories. The heterogeneous constitutive theory of the generalized FGM structure is founded in this paper by taking the design requirements of the applicable FGM structure into consideration. On the basis of that, the solution is sought for the field of displacement and stress of the heterogeneous and anisotropic FGM structure under the combined pressure of temperature loads and force loads by utilizing the generalized double Fourier series solution and the extensive form variations.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 785-789 格子間隔が傾斜したダイヤモンドフォトニック結晶の使用による電磁波の発振制御 Emission Control of Electromagnetic Wave by Using Diamond Photonic Crystals with Graded Lattice Spacing 桐原聡秀 武田三男  K. Sakoda,  宮本欽生 S. Kirihara,  M. W. Takeda,  K. Sakoda,  Y. Miyamoto  Three-dimensional electromagnetic or photonic crystals with periodic variations of the dielectric constants were fabricated by using a rapid prototyping method called stereolithography. Millimeter-order epoxy lattices with a diamond structure were designed to reflect electromagnetic waves by forming an electromagnetic bandgap in GHz range. Titania based ceramic particles were dispersed into the lattice to control the dielectric constant. The diamond lattice structures formed the perfect bandgap reflecting electromagnetic waves for all directions. The location of the bandgap agreed with the band calculation using the plane wave propagation method. The diamond structures with stretched lattice spacing were successfully fabricated as well, resulting in the directional transmission of microwaves. The stretching ratio of the lattice spacing in the crystal structure was changed according to the electromagnetic band calculation. A microwave antenna head composed of the diamond structure with a graded lattice spacing was fabricated which achieved the unidirectional transmission.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 791-795 ニューラルネットと共役勾配法を用いる金属／セラミックのFGM保護具の最適化設計 The Optimization Design of Metal/Ceramic FGM Armor with Neural Net and Conjugate Gradient Method Li-Sheng Liu, Qing-Jie Zhang , Peng-Cheng Zhai Li-Sheng Liu, Qing-Jie Zhang and Peng-Cheng Zhai  Ceramic/Metal FGM Armor is a new type armor, and it can provide more strong protection than conventional Ceramic/Metal armor for combat vehicles, because there is no significant interface between ceramic and metal, which make the FGM armor transfer the energy to larger region than conventional ceramic armor and reduce the reflected stress wave's strength, especially tensile stress wave strength, so that the hard face of ceramic can be used sufficiently. In this paper, a new kind of optimize method is advanced to research the design of FGM armor. This method is based on the neural net theory and conjugate gradient method. The process of this method is as following: (1)The impact process of the armors with different FGM layer is analyzed by numerical method or test method, in this process, two aspects of factors are taken into account, one is the design parameters of FGM armor: it includes FGM's layers number, the percent of ceramic in each FGM layer, the thickness of each FGM layer, the thickness of ceramic layer and the metal layer; another is the object parameter of optimization: the penetration depth is only one parameter. (2)The neural net theory is used to build the relation between the design parameters and object parameter. Due to the high nonlinear characteristic of this relation, it can't be expressed by ordinary function. The results of last step are as the training sample of neural net, which is made of 5 input parameters (the design parameters) and 1 output parameter (the object parameter). (3)The relation expressed by neural net is selected as the object function of optimization, then the conjugate gradient method is used to build optimization algorithm. (4)The optimized results are attained by optimization algorithm. At the end of paper, the ceramic/metal FGM armor is optimized by this method, and then validated by numerical method.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 797-801 セラミック-金属FGMメッキの高速の小さいガソリンエンジンへの応用研究 An Investigation into Application of Ceramic-Metal FGM Plating to Small High Speed Gasoline Engines Zhiyuan Sun, Qing Wang, Tiecheng Bao Zhiyuan Sun, Qing Wang and Tiecheng Bao  This paper presents the results from the investigation of the ceramic-metal FGM (functionally gradient material) plating application on small high-speed gasoline engines for motorcycles. Influences of ceramic-metal FGM plating on the engine dynamic performances, exhaust emissions, and durability have been extensively studied through experimental and analytical work. The tests show that when the engine is plated, the output can increase by 5.6%-12%, the brake specific fuel consumption can decrease by 8%-10%, and the CO and HC emissions decrease by about 30% and 25% respectively. The analysis indicates that when the engine is plated, the friction coefficient between moving parts decreases so that the frictional losses of the engine reduce. Moreover, FGM plating can effectively shorten flame quenching distance, which is the main factor to improve engine dynamic and exhaust emission performances.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 803-806 傾斜インピーダンスを持つフライヤー板による超高速発射の研究 Researches on Hypervelocity Launching by Flier-plate Materials with Graded Impedance Chuanbin Wang, Lianmeng Zhang, Qiang Shen Chuanbin Wang, Lianmeng Zhang,Qiang Shen  As a new kind of functionally graded materials, flier-plate materials with graded impedance can be used to launch a projectile material to hypervelocities (over 10m/s) for providing extremely high dynamic pressures (1-2 TPA). In order to launch the projectile to such hypervelocities, at first very high pressures are necessary. Secondly, the high pressure loading must be uniform and shockless, i.e. quasi-isentropic compression, to prevent the projectile from either fracturing or melting. For that reason, the flier-plate material must have a rational varying impedance in its thickness direction, and the hypervelocity launcher should also be designed and optimized. In the present study, the research background of flier-plate materials with graded impedance and the key points of hypervelocity launching by such materials are mainly reviewed. The application and expectation are also introduced.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 807-812 宇宙エネルギーネットワークのためのFGM概念を用いる太陽励起レーザ Solar Excited Laser using FGM Concept for Space Energy Network 藤田和久,古河裕之,山中正宣,新野正之 Kazuhisa Fujita,Hiroyuki Furukawa,Masanobu Yamanaka,Masayuki Niino  Solar excited laser (SEL) using semiconductor material is proposed for wireless energy distribution system with laser light in space. The SEL converts solar light directly to laser light suitable for long-distant transmission. Semiconductor has high controllability of its optical and electrical functions which can be utilized for realization of the SEL. AlGaAs system is taken as an appropriate material for highly efficient conversion. Potential structure of the laser device is discussed from aspects of absorption of the solar light and transfer of the produced carrier into the active layer emitting laser light. Non-linear graded potential is mentioned as a possibility to enhance the performance for the first time.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 813-818 HB型熱電モジュールから成るkW級3段カスケード型熱電力デバイスの設計研究 An Examination of the Design of a kW-Range 3-Stage Cascade-Type Thermoelectric Power Generation Device Composed of HB-Type Thermoelectric Modules 丹治雍典, 木皿且人, 新野正之 Y. Tanji, K. Kisara,  M. Niino  A practical thermoelectric power generation device heated by solar energy is designed and the possibility of manufacture is examined. The device is composed of a solar collector, a heliostat, a kW-range 3-stage cascade-type thermoelectric module and a heat radiator of cubic box type, which is designed for both ground and space use. There are used 3 kinds of modules composed of hamburger (HB)-type thermoelectric elements of GeSi, PbTe and (Bi,Sb)2(Te,Se)3 and each module has 850-900 elements. The solar collector is able to supply either 7.6kW heat on the ground or 13.3kW heat in the space.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 819-824 高エネルギー効率を持つ床暖房システムのための傾斜機能の木ベースの板の設計 Design of Functionally Graded Wood-based Board for Floor Heating System With Higher Energy Efficiency 小畑良洋, 竹内和敏, Masanobu Kawazoe,金山公三 Yoshihiro Obata, Kazutoshi Takeuchi, Masanobu Kawazoe, and Kozo Kanayama   Recycling of wood building waste has been required and wood boards are prospective recycled materials. The concept of FGM was introduced to the wood board as a base material of a floor heating system to develop an FGM board with higher energy efficiency. Two-dimensional unsteady heat transfer problem in an FGM plate with material properties of wood was analyzed, which modeled the state that the base material was heated partially. The Laplace transform and the perturbation method were applied for the analysis. The tactile warmth of a facing plate in the floor heating system, which touches to human sole directly, was discussed to avoid losing the goodness of wood.  English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 825-829 可視光駆動の新しい半導体光触媒と機能性エコ物質としてのそれらの応用 New Visible Light Driven Semiconductor Photocatalysts and Their Applications as Functional Eco-Materials J. Ye, Z. Zou, M. Oshikiri,  T. Shishido J. Ye, Z. Zou, M. Oshikiri,  T. Shishido  Two novel series of semiconductor  photocatalysts, InM04 (M=V,Nb,Ta) and RV04 (R=Y, rare earth), have been developed by crystal and electronic structure control. The new  photocatalysts have band gaps narrower than 2.6 eV and showed photocatalytic activities in evolving hydrogen from water under visible or UV light irradiation. Correlation between the photocatalytic activities and electronic structures of the new  photocatalysts were investigated.  English