边坡岩体质量分级的模糊层次分析

基于深度测量压入方法，以材料试验机Instron 5848 Microtester作为加载平台，外接高分辨力位移传感器，设计专用夹具，开发出该材料试验 机的宏观压入功能. 研究发现：对于机架柔度，无需再进行修正；对于压针接触面积， 可用相关的方法计算. 采用Oliver-Pharr方法处理测试数据，可获得材料的 硬度和弹性模量. 为了验证试验的可靠性，选用5种典型金属材料，将宏观压入测试结果与 MTS Nano Indenter XP测试结果进行对比，二者基本一致，其分散性均在10{\%}以内. 显示了开发传统材料试 验机宏观压入测试功能的可行性.     

球形压痕的残余变形分析

球形压痕技术在材料力学属性，诸如硬度，弹性模量等的测量中得到了广泛的应用。应用Twyman-Green及云纹干涉法并配合相移技术，本文对IN783合金进行了一系列的球形压痕实验研究，并对残余压痕的面内（u,v）及离面（w）变形场进行了定量测量和分析。应用面内变形测量结果，进一步对试件表面的应力一应变分布进行了分析和计算，并在离面变形场的基础上，确立了压痕周围的弹塑性边界，从而进一步应用面内的分析结果，得到材料的屈服强度。应用压痕实验的接触半径和压力并配合Tabor经验公式，本文进一步得到了材料的应力应变曲线。实验结果与已知的IN783合金相吻合。对所涉及的一系列压痕实验，本文也进行了二维有限元分析并得到了比较一致的结果。     

界面压入法测定涂层结合强度的实验研究与理论分析

采用具有新颖性的涂层压入仪，在涂层与基体之间的界面压入，可测得压入过程中载荷与压入深度的关系曲线和界面开裂的临界载荷Ｐｗ，此值可反映涂层结合强度。界面压入法适合于评价高结合强度的涂层。根据能量守恒和转化原理，并结合Ｇｒｉｆｉｔｈ处理裂纹问题的思路，可得到结合应力表达式。在具体处理上采用数值计算与实验相结合的方法来近似处理，由此可得到结合应力值。     

A Transparent Indenter Measurement Method for Mechanical Property Evaluation

An optical Transparent Indenter Measurement (TIM) method was developed for measurement of material surface mechanical properties. During the spherical indentation test, in-situ measurements of indentation-induced surface out-of-plane displacements were obtained using an integrated phase-shifting Twyman-Green interferometer. Based on elastic recovery theory and 2D finite element analyses, a procedure was developed to determine the material Young's modulus using the measured surface out-of-plane displacements. During the spherical indentation test, contact radii were also measured and used to estimate the material post-yielding true stress-strain curve using Tabor's empirical relation. An experimental TIM apparatus was assembled to test on two engineering alloys and the results showed good agreement with known material properties.     

DETERMINATION OF CREEP PARAMETERS FROM INDENTATION CREEP EXPERIMENTS

ＩｎｔｒｏｄｕｃｔｉｏｎＣｒｅｅｐｉｓｔｈｅｔｉｍｅｄｅｐｅｎｄｅｎｔｐｌａｓｔｉｃｄｅｆｏｒｍａｔｉｏｎｏｆｍａｔｅｒｉａｌｓｗｈｉｃｈｉｓｃｈａｒａｃｔｅｒｉｚｅｄｂｙａｓｔｒｏｎｇｄｅｐｅｎｄｅｎｃｅｏｆｔｈｅｃｒｅｅｐｒａｔｅｆｒｏｍｓｔｒｅｓｓσｏｎｃｏｎｓｔａｎｔｔｅｍｐｅｒａｔｕｒｅＴ .Ｔｈｅｓｅｃｏｎｄａｒｙｃｒｅｅｐｒａｔｅ εｄｅｐｅｎｄｓｏｎｓｔｒｅｓｓσａｓ ε=Ｃｃ·σｎＣ, ( 1 )ｗｈｅｒｅＣｃｉｓａｃｏｎｓｔａｎｔ,ｎＣｉｓｔｈｅｃｒｅｅｐｓｔｒｅｓｓｅｘｐｏｎｅｎｔ.Ｔｈ…     

两种物理气相沉积氮化钛涂层的结构及摩擦性能研究

分别利用磁过滤阴极弧等离子体沉积装置和直流磁控溅射装置在不锈钢基底上制备了 Ti N涂层 ,采用 X射线光电子能谱仪、X射线衍射仪和扫描电子显微镜对涂层的结构及形貌进行了表征 ;利用纳米压痕仪测定了涂层的硬度 ;在 DF- PM型动摩擦系数精密测定仪上考察了涂层的摩擦学性能 .结果表明 :与采用直流磁控溅射法在 40 0℃基底上制备的 Ti N涂层相比 ,采用磁过滤沉积装置在室温下制备的 Ti N涂层更加致密 ,表面平滑 ,最大硬度达 3 5 GPa,摩擦系数明显较小 ( 0 .1～ 0 .4) ,耐磨性较好     

Prediction of strength using flat cylindrical indentation method

Strength of structural components is predicted. Two cases have been studied to explore the possibility of determining the damage level of the materials by the flat cylindrical indentation method with the help of the finite element method (FEM). The first uses the Gurson model for analyzing the elastic–plastic damage. The second uses the Katchanov–Robotnov law to predict the creep damage. The analytical results show that the damage levels can be determined by the flat cylindrical indentation experimental method.     

用能量法分析层状材料弹性接触问题

利用能量法分析了层状材料（薄膜／基体）弹性接触问题，得到了具有一阶精度的闭合解，给出了求解薄膜弹性模量和泊松比的表达式，并与有限元的数值解进行了比较。二者比较结果表明：在工程材料范围内，理论解与数值解相差在6％以内；同时表明单相材料中剪切模量与弹性模量之间的关系也适用层状材料中的薄膜材料。在数值解的基础上，讨论了薄膜厚度与压头半径的比值对求解精度的影响，发现此比值对精度影响不大。通过对层状材料等效泊松比与等效弹性模量的定义，给出了用压痕实验测定薄膜泊松比与弹性模量的方法。     

Study of particle rearrangement during powder compaction by the Discrete Element Method

This paper presents simulations of cold isostatic and closed die compaction of powders based on the Discrete Element Method. Due to the particulate nature of powders, densification of the compact proceeds both through the plastic deformation at the particle contact and the mutual rearrangement of particles. The relative weight of each mechanism on the macroscopic deformation process depends on the contact law, the relative density, and the type of stress exerted on the particles (shear or pressure). 3D computer simulations have been carried out to investigate the role of these parameters on the deformation mechanisms of powder compacts. The effect of rearrangement is studied by comparing simulations that use a homogeneous strain field solution for which local rearrangement is omitted and simulations that include local rearrangement. It is shown that local rearrangement has some effect on average quantities such as the average coordination number, the average contact area and the macroscopic stress. The effect on averaged quantities is much stronger for closed die compaction than for isostatic compaction. However the main effect of local rearrangement is to widen the distribution of the parameters that define the contact (contact area in particular). The results of these simulations are compared to available experimental data and to statistical models that use a homogeneous strain field assumption.