聚合物流体渗流机理研究

聚合物流体在多孔介质中渗流的研究是近年来有重大进展的领域。本文介绍从力学与物理方法进行渗流机理研究的思路、主要结果和当前活跃的研究课题。流体的非牛顿性对复杂边界条件下均匀流体力学效应的影响已得到了较好的定量处理;揭示了拉伸流粘弹特性对渗流影响的机理,其定量描述则尚有待努力。进而讨论了石油工程中十分重要的非均一流体渗流的新进展,包括大分子效应与粘性指进效应及其分形描述。对于上述物理效应的综合考虑将使聚合物渗流力学研究进入新的阶段。      

MASS PRODUCTION OF NANOPARTICLES BY HIGH GRAVITY REACTIVE PRECIPITATION TECHNOLOGY WITH LOW COST

Mass production of nanoparticles at low cost has attracted much attention from industrial and academic circles. In this paper, a novel method, the high gravity reactive precipitation (HGRP) technology, of manufacturing CaCO3 nanoparticles, presently scaled-up to an annual capacity of 10,000 tons, is presented. This paper describes the process princ/ple, the process design and experiments on the syntheses of 15-30 nm CaCO3, 30-50 nm SiO2,20-30 nm TiO2, 20-60 nm ZnO, 20-30 nm ZnS, 30 nm SrCO3, 40-70 nm BaTiO3, stick-like nano BaCO3 as well as nano-fibrillar aluminum hydroxide measuring 1-10 nm in diameter and 50-300 nm in length, using liquid-liquid,gas-liquid and gas-liquid-solid reactant systems. The advantage of using the HGRP technology is illustrated by comparison to conventional methods.     

多孔介质的流变模型研究

多孔介质在应力作用下具有弹性变形和黏性变形两种完全不同的变形机制，多孔介质的弹性变形是由介质的本体有效力所致，而黏性变表则是由介质的结构有效应力所致。多孔介质的总变形为弹性变形和黏性变形的叠加，计算多孔介质总应变量的流变模型必须同时采用本体有效应力和结构有效应力（双重有效应力），而传统的流变模型仅采用Terzaghi有效应力是不妥当的，它无法正确描述多孔的应变行为，采用了双重有效应力之后的流变模型，通过调节介质特性参数，可以拟合介质的实际应变行为，并且把多孔介质与普通固体联系了起来。     

A FINITE ELEMENT ANALYSIS OF THE LARGE PLASTIC DEFORMATION BEHAVIOR OF AMORPHOUS GLASSY CIRCULAR POLYMERIC BARS

The BPA eight chain molecular network model is introduced into the finite element for-mulation of elastic-plastic large deformation.And then,the tensile deformation localization develop-ment of the amorphous glassy circular polymeric bars(such as polycarbonates)is numerically simulat-ed.The simulated results are compared with experimental ones,and very good consistence betweennumerical simulation and experiment is obtained,which shows the efficiency of the finite elementanalysis.Finally,the influences of the microstructure parameter S_ on tensile neck-propagation andtriaxial stress effect are studied.     

压电材料平面应力状态的直线裂纹问题一般解

研究了含直线裂纹系的压电材料平面应力问题单个裂纹和双裂纹问题的封闭解答表明，在裂纹尖端，应力、电场强度和电位移有１／２阶的奇异性并与前人结果比较了产生电场奇异性的物理因素     

压电材料平面应力状态的直线裂纹问题一般解

研究了含直线裂纹系的压电材料平面应力问题单个裂纹和双裂纹问题的封闭解答表明，在裂纹尖端，应力、电场强度和电位移有１／２阶的奇异性并与前人结果比较了产生电场奇异性的物理因素     

耦合蠕变损伤的粘塑性模型用于疲劳-蠕变交互作用的研究

该文对550℃下30CrMoNiV5-11转子钢进行了轴向应力控制的带保持时间的疲劳实验.按照Le-maitre有效应力的概念,采用Kachanov损伤演化方程,推导了耦合损伤的粘塑性流动方程和随动硬化方程,使用返回映射和向后欧拉方法实现应力更新,并在有限元软件ANSYS的接口程序UMAT中嵌入用户程序.对试样疲劳-蠕变交互行为进行模拟,结果表明,耦合蠕变损伤变量后,模拟结果较不含损伤变量模型的模拟结果精度大为提高.