岩石冲击损伤试验的数值流形方法模拟

主要根据岩石在冲击载荷作用下的变形与破坏特征,对现有的仅适用于模拟基于线性本构关系和恒定载荷作用下物体变形规律的数值流形程序进行了扩展.程序的扩展主要集中在3个方面:添加了由程序本身决定的程序运行终止条件,把恒定的载荷作用扩展为三角波载荷作用,改变原来的单一线弹性本构关系为由冲击损伤本构关系和线弹性本构关系共同组成的复合本构关系.最后利用扩展后的程序对冲击试验结果进行了模拟,结果与试验符合较好.     

Impact Deformation and Fracture Mechanisms of Plates of Brittle Materials

We have studied the deformation and fracture mechanisms of plates of brittle materials under impact loading. The paper presents the results of numerical simulation of impact interaction between a projectile and a multilayer plate with a brittle layer. Methods of compression and perforation testing of brittle materials have been elaborated. The results of numerical simulation are compared with the experimental data.     

正常晶粒生长形貌演化的计算机模拟研究

有关多晶材料晶体生长机理及计算机模拟方法，我们已作了详细的论述。本文以蒙特卡罗（Ｍｏｎｔｅ Ｃａｒｌｏ）方法为基础，通过对Ｑ－ｓｔｅｔｅ ｐｏｔｔｓ算法进行改进，建立快速的Ｑ－ｓｔａｔｅ ｐｏｔｔｓ算法，用Ｄｅｌｐｈｌ３．０提供的Ｏｂｊｃｅｔ Ｐａｓｃａｌ语言编写软件，在ＰＣ５８６上实现了多晶材料晶粒生长结构演化的计算机模拟及统计分析。正常晶粒演化形貌图与生产动力力学相符合，逼真度较好。生长指数的     

氧化铝瓷的显微结构与断裂韧性关系的研究

制备并收集一系列不同显微结构的９９－Ａｌ２Ｏ３瓷试样，研究晶粒尺寸及其它显微结构参数与断裂韧性Ｋ１ｃ的关系。结果表明：（１）当晶粒平均直径ｄ＞１５μｍ时，Ｋ１ｃ随ｄ的减小而升高，当ｄ＜５μｍ时，Ｋ１ｃ随ｄ的减小而迅速降低。（２）气孔的数量、分布、形貌及晶界相也影响着材料的Ｋ１ｃ值。     

Alumina versus Zirconia Comparative Survey of Thermic Influence During Dental Ceramic Core Manufacturing Process

For dental ceramic restorations, the manufacturing process presumes a high temperature sample heating treatment process, more than 1,000°C for applied aesthetic veneer and glazer. The present study presents and analyzes a comparative survey for two dental ceramics regarding the link between the heating treatment and reported cases of fractures and failure (delamination) of ceramic core. Two different dental ceramics samples were investigated: alumina based ceramic, respectively zirconia based ceramic materials. For zirconia based ceramic, changes concerning monoclinic (M) and tetragonal (T) crystalline phases occur and peak intensity variation from x-ray diffraction patterns are observed during heating process. For alumina based ceramic, the crystalline structure is less affected by the heating process but a different grain size and orientation were noticed during/after heating treatment. Both of them are affecting the strength and fracture toughness of the dental ceramic core.     

Strength and Fracture Toughness of Ceramic Materials for Metal-Ceramic Prosthetic Dentistry

The strength in biaxial flexure and the fracture toughness on indentation of the specimens of ceramic materials for the coverage of metal-ceramic prostheses were studied. The strength was established to be mainly determined by their microstructure and sintering conditions. Comparative studies demonstrated that Ultropaline and VITA OMEGA 900 ceramic compositions exhibited more uniform distribution of leucite microcrystals and higher strength and fracture toughness than Duceram Plus and IPS Classic materials.__________Translated from Problemy Prochnosti, No. 3, pp. 128 – 139, May – June, 2005.     

基于仿拟及用户情感认知的陶瓷日用品造型设计研究

目的 使陶瓷日用品更好地满足用户情感认知和现代室内设计要求,同时赋予陶瓷日用品现代元素,使其便于推广和使用。方法 以仿鹅卵石陶瓷调料罐为例,采用多指标正交试验结合仿拟设计及用户情感认知评价对调料罐外观造型进行设计研究。首先,依据鹅卵石外观及产品要素建立四因素三水平的等水平正交表;其次,利用感性工学方法筛选出两个最贴切的词汇,采用Likert7级量表对各个方案进行用户情感认知量化;最后,以用户情感认知的量化数据为基准,将极差分析结果与方差分析结果相结合,得到满足用户情感认知的最佳外观造型方案。结果 完成仿鹅卵石陶瓷调料罐外观造型设计,建立一种结合仿拟设计和用户情感认知的陶瓷日用品外观造型设计研究思路。结论 将仿拟设计与用户情感认知相结合,可以使产品、设计师和用户三者紧密相连,更精确地对陶瓷日用品进行优化处理,得到优化后的外观造型设计参数,同时为今后的陶瓷日用品造型设计提供可靠的参考。     

碱金属铌酸盐铁电陶瓷的研究进展

综述了LiNbO3、NaNbO3和KNbO3系无铅铁电陶瓷的最新研究进展及应用.对碱金属铌酸盐体系的掺杂和改性作了总结.介绍了目前制备铌酸盐陶瓷粉体所用方法,重点说明了水热法在碱金属铌酸盐陶瓷材料制备中的研究和应用现状.并展望了铌酸盐系无铅铁电陶瓷的发展趋势.     

热等静区致密化的计算机模拟及在TZP陶瓷中的应用

根据热等静压的致密化理论,建立热等静压致密化的数学模型,实现了数学模型的计算机模拟,完成了热等静压图计算机计算、绘制与分析.对3Y-TZP的热等静压图进行了实验验证,实验结果与理论计算结果十分吻合.利用热等静压图,讨论了热等静压参数优化问题.     

热等静区致密化的计算机模拟及在TZP陶瓷中的应用

根据热等静压的致密化理论,建立热等静压致密化的数学模型,实现了数学模型的计算机模拟,完成了热等静压图计算机计算、绘制与分析．对３Ｙ－ＴＺＰ的热等静压图进行了实验验证,实验结果与理论计算结果十分吻合．利用热等静压图,讨论了热等静任参数优化问题．     

Semianalytic Finite-Element Method in Continuum Creep Fracture Mechanics Problems for Complex-Shaped Spatial Bodies and Related Systems. Part 2. Analysis of Reliability of the Results and Efficiency of the Method,and Algorithms for Solving the Problems

We perform analyses of convergence and reliability of the results of solving continuum creep-fracture problems and efficiency of the semianalytic finite-element method for heterogeneous circular nonclosed bodies.     

聚合物分解法制备微波介质陶瓷粉体的研究

对采用聚合物分解（Ｐｅｃｈｉｎｉ）法制备ＭｇＴｉＯ＿３粉体进行了研究。通过对聚合中间产物进行红外光谱分析，研究了聚合物分解法制备ＭｇＴｉＯ＿３陶瓷粉体的聚合反应过程及产物。并与用传统固相反应法制备粉体工艺进行对比．从而证明用聚合物分解法可获得单一ＭｇＴｉＯ＿３相材料．并可降低粉体的煅烧温度。     

SiO_2/SiCN核壳陶瓷微球的制备及表征

采用乳液技术和先驱体转化法相结合,利用改性后SiO_2颗粒表面的双键引发聚硅氮烷(PSN)原位聚合,得到SiO_2/PSN核壳结构微球,经高温裂解过程成功制备SiO_2/SiCN核壳陶瓷微球。研究SiO_2与PSN原料的质量比、固化时间和热解温度对核壳微球形成过程和形貌的影响,并采用SEM,EDS,TEM,FT-IR,XRD对微球的微观形貌、化学成分及物相进行表征。结果表明:SiO_2与PSN质量比为1∶4时,200℃固化4h得到表面颗粒分布均一、包覆完全的SiO_2/PSN核壳微球;经800~1200℃热处理后,得到能保持原来形貌的非晶态SiO_2/SiCN核壳陶瓷微球;1400℃热解产物发生结晶,生成了SiO_2,SiC和Si_3N_4晶相。     

基于修正Anderson 模型的冲击载荷下地基振动响应预测方法

提出了一个预测潜在冲击载荷下振动效应的理论模型与现场实测相结合的综合预测方法。通过一系列具有针对性的室外重锤冲击振动试验,以及现场实测数据对Anderson模型进行了验证并修正,然后利用修正的Anderson模型预测冲击荷载的振动效应。将预测结果和现场试验结果进行对比分析,结果表明:预测结果与实测结果吻合较好。     

复合材料飞轮损伤与断裂的结构模拟

本文对复合材料飞轮的受力与损伤情况进行了分析;设计了多种模拟复合材料飞轮的断裂与损伤的静态加载结构,这些结构为用声发射方法检测复合材料飞轮的断裂与损伤的研究工作带来了很大方便,实验证明是可行性的.     

传统压痕法识别陶瓷材料断裂韧性的有效性研究

基于虚拟裂纹闭合法对传统压痕法测试陶瓷材料断裂韧性的数值模型进行计算,以此为基础,分析比较传统压痕法的几种典型公式识别陶瓷材料断裂韧性的测试误差和所测材料的适用范围。结果表明:传统压痕法的Anstis公式较Evans公式,Lawn公式,JISR公式和Niihara公式,在材料比功0.3≤We/Wt≤0.45时所测断裂韧性值与理论计算值较为接近,其最大误差为12.9%,测试结果相对准确;当0.45We/Wt≤0.7时,传统压痕法对陶瓷材料断裂韧性的测试误差随比功增加迅速增大,特别是当We/Wt=0.7时,Anstis公式,Evans公式,Lawn公式,JISR公式和Niihara公式所测断裂韧性值与理论计算值的最大误差分别为70%,148.5%,48.8%,98.7%和166.6%,在此材料比功范围内传统压痕法所测断裂韧性值误差较大。     

Computer Simulation of Physical and Mechanical Processes Running in the Reaction Cells of High-Pressure Installations in the Course of Synthesis of Diamonds

We study the problem of finite-element simulation of coupled nonlinear nonstationary processes of electric conductivity, heat conduction, and thermoplasticity taking into account the phase transitions in the materials. As a practical application, we develop a procedure of computer simulation of the process of spontaneous crystallization of diamonds. We solve the problem of determination of the fields of temperature, stresses, and concentrations of phases in the reaction volume of a high-pressure installation and in the local diamond–melt–graphite system in the course of crystallization of diamonds. It is discovered that these fields are strongly coupled, the solutions obtained for the reaction mixture and local system are characterized by a pronounced mutual influence, and the effect of self-regulation of pressure in the reaction zone exists and takes the form of oscillations of pressure about the line of the graphite–diamond phase transition.     

基于BP神经网络的压电陶瓷蠕变预测

压电陶瓷驱动器的蠕变误差随时间呈现非线性变化,难以实时修正。提出基于BP神经网络的压电陶瓷蠕变预测方法,使用压电陶瓷驱动系统采集数据,对数据进行归一化处理,通过实验设计BP神经网络的隐含层数、隐含层节点数、节点转移函数和训练函数,构建BP神经网络预测模型,建立压电陶瓷蠕变与时间的关系。用BP神经网络模型对压电陶瓷蠕变进行了预测仿真,并将结果与实测数据进行了对比。结果表明,蠕变预测结果与实验数据的最大绝对误差均小于0.1 μm,最大蠕变误差均不超过0.6%,最大均方误差仅为0.0021,可见,BP预测模型具有较高的预测精度,可作为预测压电陶瓷蠕变误差的一种有效手段。