Finite element analysis of partly wrinkled reinforced prestressed membranes

Wrinkling is a well known phenomenon experimented by tension membranes in Civil Engineering applications. This paper will present an efficient numerical technique for the computational simulation of such wrinkles in a prestressed membrane. In particular, the relaxed energy approach (Pipkin in IMA J Appl Math 36:85–99, 1986) is particularized for prestressed membranes (Gil in Textile composites and inflatable structures, CIMNE, 2003) undergoing moderate strains. Wrinkling conditions in terms of the Euler-Lagrange finite deformation tensor along principal directions will be obtained. This will provide a framework to describe properly the initial instant when wrinkles start to be encountered in a prestressed Saint Venant–Kirchhoff hyperelastic membrane. Subsequently, a modified Helmholtz’s free energy functional will be introduced with the purpose of describing the modified constitutive behaviour of the continuum after the onset of wrinkling. Consistent derivations of the stress tensor as well as the constitutive tensor will de depicted. The results will be particularized for membranes and cables in a Finite Element discretization basis. Some numerical examples will prove the accuracy and robustness of the described algorithm.     

烧结通用配料计算软件系统的开发

本文介绍了烧结通用配料计算软件系统的总体结构，软件的功能及其设计特点，该软件已在多个烧结经验中得到成功应用。     

微波热液法制备光催化TiO2功能材料

采用微波加热法，研究了钛配离子热分解水解反应的规律。结果表明，水解产物在大气气氛和300℃下煅烧2h，所得产物为锐钛型TiO2粉末。在紫外线照射下，乙酸经Ti02光催化反应12h后，残余量小于初始量的20％。     

Cohesive stresses and size effect in quasi-brittle materials

A novel approach to the derivation of Bažant’s size effect law is presented. Contrarily to the original Lagrangian derivation which hinged on energetic consideration, a Newtonian approach based on local stress intensity factors is presented. Through this approach, it is shown that Bažant’s size effect law is the first (and dominant) term in a series expansion for the nominal stress. Furthermore, analytical expressions forB are derived for selected specimen geometries.     

如何正确选择合适的耐蚀材料

文章较全面的介绍了如何根据设备、装置、构件所处的工作环境及使用条件进行防腐蚀设计,及其防腐蚀设计的内容和注意事项,选择合适的防腐蚀材料,确保产品的使用寿命     

弹性筛管防砂技术

弹性筛管防砂技术是根据稠油油藏高轮次吞吐和蒸汽驱井防砂生产需要而研制的筛管防砂新技术。进行了筛管结构优化、加厚过滤单元外罩设计、固定方式研究、弹性过滤材料筛选、防腐实验研究等。室内试验表明，筛管的过流能力在900cm^2／m以上、渗透率在100μm^2以上、筛管抗内、外压强度达到20MPa、防砂粒径在0.1mm以上、耐温350℃、pH值在3～12之间不被腐蚀。现场试验证明，该技术防砂和抗堵塞性能好，防砂有效期长，地层适应性强，施工简便，防砂生产效果明显，具有良好的应用前景。     

焦化生产中含硫容器自燃氧化倾向性分析

分析了炼焦化工生产过程中硫的分布和存在形态、硫铁化合物自燃的影响因素,提出了防止储罐、管道等设备自燃事故的安全控制方法.     

Development of sealing compositions with nanostructure iron-based fillers

The possibility of utilizing nanopowders of iron and Fe-Co-Ni produced bu a thermochemical method in the fabrication of sealing composition materials is investigated. It is established that such hermetic sealing composition materials function reliably under extremal conditions and guarantee elevated strength of adhesion to the surface of the metal and high corrosion and temperature stability. __________ Translated from Poroshkaya Metallurgiya, Nos. 3–4(448), pp. 112–117, March–April, 2006.     

纳米镍粉的制备工艺及产业化研究进展

综述了纳米镍粉的制备方法(包括物理法和化学法)及产业化现状,对纳米镍粉的各种制备方法进行了分析和评价。与物理法相比,化学法的产量高、成本低廉,能制备出性能优异的纳米镍粉,适合规模化生产;使用化学法制备的纳米镍粉的纯度、粒径及成本的控制仍需进一步加强。同时,对今后纳米镍粉的制备和产业化发展提出了建议。