梯度功能材料的研究评述

叙述了梯度功能材料（FGM）的概念，结构特征以及制备方法。评述了梯度功能材料研究的现状，提出了将梯度功能材料与纳米材料、梯度功能材料与智能材料系统地结合，将是21世纪材料科学发展的主导方向之一。     

受内压力的功能梯度材料圆筒应力分析

本文在有限元单元内部采用等参变换方法模拟材料特性的梯度变化，提出了适合功能梯度材料应力分析的有限元法，并用该法分析了受内压力的功能梯度材料圆筒应力分布情况。     

W-Cu功能梯度材料的研究现状

W-Cu功能梯度材料是一种新型非均质复合材料。介绍了W-Cu功能梯度材料的基本特征及用途,综述了W-Cu功能梯度材料的制备方法,并介绍了电沉积法在制备功能梯度材料中的应用情况,分析了其制备W-Cu功能梯度材料的可行性,最后提出了今后W-Cu功能梯度材料需要解决的问题。     

基于组分磁性差异制备ZrO2/Ni功能梯度材料研究

根据不同组分的磁性差异，提出一种在梯度磁场中，采用粉浆浇注法制备铁磁性／非磁性功能梯度材料的方法，并用此方法制备出成分连续变化的ZrO2／Ni功能梯度材料．采用能谱分析仪、光学显微镜和X射线衍射仪对ZrO2／Ni功能梯度材料的成分分布、微观结构和相组成进行了研究．结果表明，在0．5T／m的磁场梯度作用下，浆料中Ni和ZrO2颗粒由于所受磁场作用不同而发生重新排列，形成沿样品厚度方向成分的梯度分布．此外，建立了功能梯度材料成分与颗粒粒度、饱和磁化强度以及磁场梯度之间的定量关系．     

Al2O3—Ti系梯度功能材料残余热应力有限元分析

采用有限元方法对Ａｌ２Ｏ３－Ｔｉ系梯度功能材料在制备过程中产生的残余热应力进行了线弹性分析，详细讨论了梯底层数目，梯度层厚度和成分梯度指数对应务大小和分布的影响，确定了各项最佳参数。非梯度功能材料与优化后的梯度功能材料的残余热应务对比结果显示；梯度功能材料缓和热应力的效果十分显著。     

功能梯度材料：回顾与展望

本文阐述了功能梯度材料的种类、主要制备方法以及国内外研究进展和应用，对该领域的几个重要点问题进行了讨论。此外，提出了一种新的梯度材料制备方法－等离子喷焊法，分析了该法的特点。     

功能梯度材料:回顾与展望

本文阐述了功能梯度材料的种类、主要制备方法以及国内外研究进展和应用，对该领域的几个重要热点问题进行了讨论。此外，提出了一种新的梯度材料制备方法——等离子喷焊法，分析了该法的特点。     

基于坐标变换的功能梯度材料空间映射建模研究

随着3D打印零件复杂性和多样性的日益增加,单一材质的零件已无法满足各类特殊性能要求,功能梯度材料零件逐渐成为快速成型制造行业的研究热点。为满足功能梯度材料的制造要求,提出了一种基于坐标变换的功能梯度材料空间映射建模方法,该方法的关键是将几何信息与材料信息有效结合。首先,采用单梯度源法、多梯度源法构建功能梯度材料模型的材料空间,在遇到交叉梯度源模型时利用特定的相交算子以一定的权重比进行材料分布计算。然后,在几何空间与材料空间结合的过程中,巧妙地通过坐标变换将材料空间与几何空间的坐标系重合,实现将材料空间映射至几何空间,从而得到带有材料信息的功能梯度材料模型。通过修改梯度源、材料分布函数以及坐标变换方法即可获得所需的功能梯度材料模型。利用Visual Studio 2019软件和OpenGL编程语言对实例模型进行可视化分析的结果表明,所提出的建模方法相比于大部分估值建模、非估值建模方法可大大缩短建模时间,从根本上解决了某些算法所造成的储存空间不足和建模过程繁琐等问题。基于坐标变换的功能梯度材料空间映射建模方法为增材制造行业提供了一种新的建模方法,具有良好的应用价值。     

梯度功能材料的复合镀工艺

梯度功能复合镀技术是制备梯度功能材料的重要方法之一，具有控制简单，可处理复杂工件，投资少等优点。本文对该技术用于制备梯度功能材料的原理、特点及应用作了综述。     

Al3O—Ti系梯度功能材料残余热应力的有限元分析

采用有限元方法对Ａｌ２Ｏ３－Ｔｉ系梯度功能材料在制备过程中产生的残余热应力进行了线 性性分析。详细讨论了梯度层数目、梯度层厚度和成分梯度指数对应力大小和分布的影响，确定了各项最佳参数。非梯度功能材料与优化后的梯度功能材料的残余热絷力对此结果显示：梯度功能赫兹 热应力的效果十分显著。     

A systematic approach for Integrated Computer-Aided Design and Finite Element Analysis of Functionally-Graded-Material objects

Computer-Aided Design (CAD) and Finite Element Analysis (FEA) of Functionally-Graded-Material (FGM) objects are generally regarded as separate domains of interest in CAD and Computer-Aided Engineering (CAE) community. Such a separation of CAD modeling and FEA of FGM objects makes it cumbersome and tedious for both designers and engineers to exchange the necessary information in the entire design process. Without appropriate CAD models, complex material distributions can hardly be represented and the FGM objects under examination remain simple in material variations (e.g. unidirectional gradations). With CAD modeling tools only, the end users are still uncertain whether or not the designed objects can really meet the functional requirements in terms of structural, thermal or other prescribed properties. This paper proposes a systematic approach to integrate these domain-dependent design tools in FGM object design. Integrated solutions to CAD modeling and property analysis of FGM objects are utilized to design complicated (bi-directional or even tri-variate) FGM objects. Complex FGM distributions are encoded into the proposed Heterogeneous Feature Tree (HFT) structure; and the material compositions of a given point of interest are interrogated from the CAD models at runtime. Integrated FEA of FGM objects are then carried out by establishing a link between the proposed CAD modeler (CAD4D) and a commercial FEA package (COMSOL Multiphysics). Four different (three unidirectional and one bidirectional) FGM objects are modeled with traditional analytic function based approaches and the proposed methods. Under the same thermal and mechanical conditions, the properties of each model are compared in terms of temperature fields, residual thermal stresses and the strain energy densities. Results show that the proposed approach can facilitate the design of complex FGM objects in a systematic way.     

梯度功能材料的研究

梯度功能材料是五年前由日本科学家提出的新概念和新思想,其两侧由不同性能的材料组成,以对付苛刻的使用环境;而中间部分的组成和结构又是连续变化的,使其内部界面消失,以减小和克服结合部位的性能不匹配因素。这类材料在航天事业和核工业中有看广阔的应用前景和极高的使用价值。本文着重介绍了梯度功能材料的设计思想、目前的研究现状、以及我们在这方面做的一些工作。并综述和比较了各类制备工艺技术。     

Experimental Investigations on Deformation and Fracture Behavior of Glass Sphere Filled Epoxy Functionally Graded Materials

In this paper, deformation and fracture behavior of glass sphere filled epoxy functionally graded materials (FGM) are numerically evaluated and experimentally studied. The fabrication of the FGM is described in detail, and the spatial gradation of elastic modulus and the microscopic structure in FGM are measured and analyzed. The deformation and fracture characterization of the FGM specimen with a crack oriented along the direction of the elastic gradient under three point bend are studied by the experimental and the finite element method. The influences of crack location at both the stiff and the compliant sides of the FGM specimen on crack initiation, deformation field and stress intensity factor are analyzed. The results are: (a) The neutral-axis in the FGM specimen under three-point-bending will shift toward the stiffer side; (b) The initial fracture load increases with the increase of elastic modulus at the crack tip; (c) The elastic gradients shield a crack on the compliant side and lower the stress intensity factor when compared to the one with crack on the stiff side. These results will be useful for better design and reliable evaluation of FGM.     

Microstructural design of connective base cells for functionally graded materials

Control of compositions and microstructures plays a significant role on developing functionally graded material (FGM). The existing fabrication technologies allow placing multiple compositions in such a way that a desirable gradient of effective physical properties can be achieved. It is interesting to explore how to design microstructure for the same purpose. This paper introduces an inverse homogenization procedure to FGM design. A quasi-periodic base cell (PBC) is optimized for attaining a specific gradient of Young's modulus. To ensure proper connectivity between adjacent PBCs, heat sinks originally used in thermal conduction problem are employed as connection constraints. The capability of this technique is demonstrated by the examples of FGM microstructural design.     

含FGM的涂层结构中热残余应力的分析与优化

本文利用有限元方法和优化理论,对含ＦＧＭ（Ｆｕｎｃｔｉｏｎａｌｌｙ　Ｇｒａｄｅｄ　Ｍａｔｅｒｉａｌｓ）层的热喷涂构件中的残余应力进行了数值分析,并获得了ＦＧＭ内各组份体积含量分布的最优化形式和参数ｐ。同时,我们也研究了喷涂构件的几何形状、涂层及基底的材料性能对于ｐ的影响规 律。在本文的分析中,考虑了基底材料和ＦＧＭ的塑性变形以及其性能对于温度的依赖。本文 的工作将有利于含ＦＧＭ层的热喷涂构件的设计与生产。     

功能梯度表面涂层热锻模的仿真设计与分析

针对热锻模损伤主要发生在模具表面的情况,构想使用梯度功能材料对均质材料制造的热锻模进行表面处理,阐述了梯度材料锻模表面涂层的设计方法,建立了基于Deform软件的热锻成形有限元模型,分析对比了均质热锻模与梯度材料表面涂层热锻模在锻造生产后的温度场和应力场,从而论证了在热锻模表面进行梯度材料表面复合涂层处理的优越性。     

Multi-objective design optimization of functionally graded material for the femoral component of a total knee replacement

The optimal design of complex systems in engineering requires pursuing rigorous mathematical modeling of the system’s behavior as a function of a set of design variables to achieve goal-oriented design. Despite the success of current knee implants, the limited life span remains the main concern of this complex system. The mismatch between the properties of engineered biomaterials and those of biological materials leads to insufficient bonding with bone, stress shielding effects and wear problems (i.e. aseptic loosening). The use of a functionally graded material (FGM) for the femoral component of knee implants is attractive because the properties can be designed to vary in a certain pattern to meet the desired requirements at different regions in the knee joint system, thereby decreasing loosening problem. However, matching the properties does not necessarily guarantee the best functionality of the knee implant and there is a need for developing the optimal design of an FGM femoral component that is longer lasting. In this study, therefore, a multi-objective design optimization of a FGM femoral component is carried out using finite element analysis (FEA) and response surface methodology (RSM). The results of using optimized FGM are then compared with the use of standard Co–Cr alloy in a femoral component knee implant to demonstrate relative performance.     

梯度功能材料的研究现状与展望

综述了国内外梯度功能材料(FGM)的研究现状,介绍了梯度功能材料的优化设计原则、制备工艺与特性评价,其中重点介绍了梯度功能材料制备工艺的基本原理和工艺方法,如粉末冶金法、气相沉积法、自蔓延高温合成法、热喷涂法、电沉积法、激光熔敷法等,分析了各种制备工艺技术存在的利弊,展望了梯度功能材料的发展前景与方向.     

Design optimization of functionally graded dental implant for bone remodeling

Despite a great success, one of the key issues facing in dental implantation clinic is a mismatch of mechanical properties between engineered and native biomaterials, which makes osseointegration and bone remodeling problematical. Functionally Graded Material (FGM) has been proposed as a potential upgrade to some conventional implant materials like titanium for selection in prosthetic dentistry. The idea of FGM dental implant is that the property would vary in a certain pattern to match the biomechanical characteristics required at different regions in the hosting bone. However, mating properties do not necessarily guarantee the best osseointegration and bone remodeling. No existing report has been available to develop an optimal design of FGM dental implant for promoting a long-term success. This paper aims to explore this critical issue by using the computational bone remodeling and design optimization. A buccal–lingual sectional model, which consists of a single unit implant and four other adjacent teeth, was constructed from computerized tomography (CT) scan images. Bone remodeling induced by use of various FGM dental implants is calculated over the period of 4 years. Based upon remodeling results, response surface method (RSM) is adopted to develop a multi-objective optimal design for FGM implantation FGM designs.     

Minimizing Thermal Residual Stress in Ni/Al₂O₃ Functionally Graded Material Plate by Volume Fraction Optimization

The thermal residual stress in the fabrication of functionally graded material (FGM) systems can give rise to various mechanical failures. For a FGM system under a given fabrication environment, the thermal residual stresses are determined by the spatial distribution of its constituent components. In this study, we optimize a Ni/Al₂O₃ FGM plate aiming at minimizing the thermal residual stresses through controlling its compositional distribution. Material properties are graded in the thickness direction following a power law distribution in terms of the volume fractions of constituents (P-FGM). An analytical model and a hybrid genetic algorithm with the pattern search are employed to predict and to minimize the thermal residual stresses, respectively. Simulation results show that an optimal design of the FGM plate could help fulfill its potential in reducing the thermal residual stresses.