考虑温度影响的平盖加筋封头结构应力强度分析

对某加热器的平盖加筋封头考虑其既受热又受内压的情况,运用有限元分析软件ANSYS对其在两种载荷下分别单独进行应力强度分析,并重点介绍了热应力分析方法。运用ANSYS耦合分析功能,在两种载荷同时作用下对平盖加筋封头结构进行应力强度分析。分析了温度载荷对平盖加筋封头结构应力强度的影响。     

球冠形封头的应用和优化设计

就工程设计中的实例 ,比较了平盖和球冠形封头的应用 ,并就球冠形封头的优化设计和制造中的问题提出个人见解。     

压力容器碟形封头内压下的弹性失稳的分析

压力容器封头，作为压力容器的主要部件之一，其结构形式已经十分成熟，以受力情况进行排序，最优的是球形封头，其次是椭圆形封头、然后是碟形封头，平盖封头受力最差，其中受力好的封头形式计算厚度相对较薄。然而在计算的过程中遇到了一些计算不合格的情况，通过查阅资料和标准对该情况进行理论分析，并采用解析解和应力分析的方法对封头最小厚度进行了详细的计算，最终可以节省材料40%。     

有限元分析在平盖设计中的应用

利用有限元软件对平盖加筋的结构进行了模拟,得到了应力分布云图和位移分布图及位移变化曲线,并采用第四强度理论对其进行了强度校核。所得结论对今后平盖结构设计具有指导作用。     

容器平盖封头样式的分析与探讨

核化工设备中许多非标贮槽的封头采用的是平盖形式,本文分别就平板封头与折边平封头应用在贮槽顶部与底部情况下进行了计算与分析,对比两种封头样式的应力强度。根据计算的结果,提出选择样式与必要时加强方案的参考建议。     

平盖封头加热炉壳体开裂事故分析

通过对采用平盖封头设计的加热炉开裂事故进行分析,找出裂纹产生的原因,并提出相应的改进措施.     

螺栓连接加筋平盖的优化设计探讨

对某台设备的螺栓连接平盖的在充氮保护工况下密封失效的问题进行分析,将其平盖进行优化为加筋平盖,以螺栓连接加筋平盖为讨论对象,在参考标准中和其它已投入的类似结构的基础上,从强度以及刚度两方面进行分析,对平盖以及加强筋的形式和尺寸进行优化设计,最终取得了较好的效果。     

大直径玻璃钢塔器平封头的优化设计

探索大直径平封头合适的计算方法。对平封头结构进行优化设计:采用平板加筋结构。利用有限元分析软件对其结构进行模拟计算,得出应力应变云图,并对其校核。为大直径平封头的设计提供了一种方法。     

大直径带支撑平盖封头的设计

对大直径平盖封头的设计，提出了一种GB150-1998《钢制压力容器》中未能确定的带支撑平盖封头的结构形式和尺寸。在参考了其他标准中类似结构和借鉴了国外已投入使用的结构的基础上，对带支撑平盖封头的结构进行有限元应力分析计算，得到全国压力容器标准化委员会的评定认可。     

具有等斜度过渡锥的无折边球形封头最佳结构参数的探讨

无折边球形封头的特点之一是采用较薄的封头与较厚的筒体相连接,从而减轻了结构的重量。封头与简体不等厚度之间连接的形式很多。本文则针对具有等斜度过渡锥的无折边球形封头作了应力分析。目前,国内多数是采用有限单元法,本文是在解析解的基础上,对简体外径与内径之比K=1.1～1.2,球冠壁厚与简体壁厚之比M=0.5=0.75,球冠半中心角α=74°～89°范围内的400种方案进行了应力计算。计算是利用TRS-80微型计算机进行的。从控制边缘应力着手,根据所取得的400种方案的应力值,对这类无折边球形封头的最佳结构参数提出了参考性意见。     

Head to head polymers. XXV: Properties of head to head polyisobutylene

Head-to-head polyisobutylene, prepared by the Grignard coupling reaction of 2,2,3,3-tetramethyl-1,4-dibromobutane had molecular weight of 3,000 to 10,000 and was characterized by wide angle x-ray diffraction, optical microscopy and thermal behavior. Head-to-head polyisobutylene is crystalline, with a crystalline melting point of 187°C and a glass transition temperature of 87°C (measured by DSC at a scan rate of 20°/min.); these values compare to a glass transition temperature of head-to-tail polyisobutylene of similar molecular weight of ?61°C and a crystalline melting point of 5°C, which can only be observed when the sample was stretched. The maximum rate of degradation of head-to-head polyisobutylene (20°/min. programmed temperature increase) is at 315°C, 70°C lower than that of head-to-tail polyisobutylene.     

Head to head polymers

Blends of head to head polyisobutylene and amorphous head to tail polyisobutylene were prepared by casting films of the polymer mixtures from o-dichlorobenzene. The glass transition behavior of the polymer blends was studied by DSC analysis. Two glass transition temperatures were observed over almost the entire composition range which indicates that the two structurally similar head to tail and head to head polyisobutylenes are not miscible even in the molecular weight range of 3000 to 5000.     

Head to head polymers

Blends of poly(-caprolactone) with either head-to-head or head-to-tail poly (vinyl chloride) were prepared by solvent casting in the form of films and their glass transition temperatures were determined by DSC analysis. The DSC scans of the blends of both poly(vinyl chloride) isomers were very similar. For blends containing 25% and 50% of poly(-caprolactone), a single transition step, a T_g, was observed, whereas for a blend containing 75% of poly (-caprolactone) three transition steps were observed, one glass transition and also a crystallization and a melting transition.Part 19: H. Kawaguchi, J. Muggee, Y. Sumida and O. Vogl, Polymer (London), in press     

Head to head polymers

Pure head to head (H–H) addition polymers, such as H–H polyolefins, H–H acrylates and H–H poly(vinyl halides), have been of interest for the understanding of the structure/properties relationship of addition polymers. These polymer structures have provided challenges of synthesis, characterization and of the measurements of their mechanical and rheological properties. H–H polymers have never been prepared by direct synthesis and indirect polymerization techniques have to be used. Some of the H–H polymers, the polyolefins, were made by polymerization of properly substituted dienes followed by hydrogenation. The H–H polyacrylates were synthesized by copolymerization followed by polymer reactions and the poly(vinyl halides), by halogenation of poly(1,4-butadiene). Improved halogenation techniques for poly(1,4-butadiene) have made H–H poly(vinyl chloride) and H–H poly(vinyl bromide) accessible in larger quantities and have allowed an extensive characterization of these polymers.

Blends of H–H with H–T polymers as well as H–H polymers with other polymers were studied. H–H Poly(vinyl chloride) or poly(vinyl bromide) blends with polycaprolactone and poly(methyl methacrylate) were also investigated. The thermal behavior and the thermal degradation behavior of these blends were investigated. The most striking result of these investigations was that H–H and H–T poly(vinyl chloride) are immiscible as is H–H and H–T polyisobutylene over almost the entire range of compositions.     

可调式跌水网格混合器设计参数对水头损失的影响

通过中试试验,研究可调式跌水网格混合器的主要设计参数对水头损失的影响。试验结果表明:影响水头损失的各因素由主到次为网格间距、调节高度和网孔大小,且网格间距对水头损失的影响呈显著性;水头损失随调节高度、网格间距和层数的增加而变大,随网格开孔率的减小而略有增加;设置多层网格和较大的网格间距可使水流形成良好的湍流结构,在混合过程中形成涡旋串级,产生高比率、高强度的微涡旋;由试验数据可拟合出摩擦系数和雷诺数的关系,得到水头损失公式,进而为设备选型和工艺设计提供参数。