一种新型无游梁抽油机的设计与分析

鉴于传统游梁式抽油机在结构和工作原理上有诸多限制,提出了一种新型无游梁式抽油机的创新设计方案。根据经典力学平衡原理,采用变力矩配重机构来完成对减速器输出扭矩辅助做功,并结合具有良好弯曲性能的扁钢丝绳作为抽油机牵拉绳索,利用桁架结构保证抽油机长期稳定运转,由带传动和齿轮减速器完成对电机的第一级和第二级的减速工作,用空间来换取效率,以降低电机的平均功率,从而实现节能减排的目的。     

基于FastICA去噪和改进HHT的转子不平衡故障特征提取方法研究

针对转子不平衡振动信号非平稳性并伴随较强环境噪声的特点，提出一种基于快速独立分量分析（FastICA）和改进希尔伯特-黄变换相结合的故障特征提取方法。该方法采用FastICA法去除环境噪声等因素对于故障特征提取精度的影响，再利用自适应白噪声总体平均模态分解方法将故障信号分解为一系列固有模态函数（IMF），并采用基于相似性评估的虚假IMF选择算法将与故障信息无关的虚假IMF分量剔除，从而保证故障信息提取的准确性和有效性。通过仿真分析证明了所提方法的有效性，并且实际试验表明：该方法可有效提取转子不平衡信号的故障特征，为该类故障的诊断提供了一种切实可行的方法。     

等离子熔积直接成形形状特性的基础研究

系统分析了熔积成形技术中影响成形形状特性的原因,研究了转移弧电流、扫描速度和起弧高度对成形精度的影响机理.实验表明,以上参数对等离子熔积直接成形形状特性的影响显著,对改善零件的成形精度起决定性的作用;通过优化成形工艺参数,焊道表面质量得到显著好转.     

高转化率SBR1712的合成和性能

分子量调节剂叔十二碳硫醇(TDM)采用分批加入方式,TDM补加量为0.35～0.45份;选用歧化松香酸钾和脂肪酸钠复合乳化剂,采用一次加入方式;在聚合速率为(7～8)%/h时,可制备出转化率达70%±2%的充油丁苯橡胶SBR 1712(充油量27.3%).在10L釜中进行扩大试验,所得试样的性能与JSR公司同类产品的性能相当.     

Adhesion Mechanisms of Polyurethanes to Glass Surfaces I. Structure-Property Relationships in Polyurethanes and Their Effects on Adhesion to Glass

Polyurethanes were prepared from toluene diisocyanate (TDI), 1-4-butane diol (BDO) and polycaprolactone-based triols with varying molecular weights. Among each molecular weight triol-based urethane, hard segment content was varied from 20% to 70%. Differential scanning calorimetry, tensile testing, and Iosipescu shear testing were done on all the various urethanes prepared. Thermal characterization data revealed the dependence of phase separation on hard segment content as well as on the triol molecular weight. Tensile data and Iosipescu shear data further confirmed the observations made from the DSC data. The data further indicated that phase separation can greatly improve the modulus of cross-linked segmented urethanes. Adhesion of these urethanes to glass surface was evaluated using soda-lime float glass plate. Urethane samples were cast on the air side of the glass plates and adhesion was measured in shear mode. Adhesion data indicated that in addition to hard segment content, modulus, cross-link density, and molecular weight of the triols, phase separation seems to be a major factor in controlling adhesion. Surfaces of the failed adhesion samples were also analyzed and the failure mode was found to be cohesive, in varying degree, with the different urethane systems.     

浅析武汉建筑的历史变迁及发展前景

该文通过分析武汉历史古建筑、历史街区、近代建筑及现代建筑的特色,提出了建设武汉未来城区的建议。     

基于特征的液压集成块的三维实体造型

本文阐述了在以ＡｕｔｏＣＡＤＲ１２．０高级造型扩展ＡＭＥ（ＡｄｖａｎｃｅＭｏｄｅｌｉｎｇＥｘｔｅｎｓｉｏｎ）为支撑软件,运用ＡｕｔｏＬＩＳＰ人工智能语言进行二次开发,编制基于特征的液压集成块三维实体特征造型软件,使设计液压集成块内部孔道时,更为直观,方便快捷。     

Fatigue crack/residual stress field interactions and their implications for damage-tolerant design

Residual stress fields are now widely accepted to have significant influence on fatigue crack growth. Tensile stresses have detrimental effects on fatigue lives, whereas compressive residual stresses can be beneficial. Control of fatigue lives via residual stress is now established in many industrial applications, using techniques such as shot peening or cold expansion. However, knowledge of the processes that occur when a fatigue crack grows through a pre-existing stress field is far from complete. Although the residual stress field will clearly have an effect on crack growth, the crack will equally have an effect on the residual stress field. The determination of this effect is not trivial, and direct measurement may be the designer’s best safeguard. This article outlines the complementary effects that a growing fatigue crack and a residual stress field have on each other. Two types of residual stress field are considered: mechanically induced and thermally induced. The results are discussed in terms of the implications that residual stress interactions have for damage-tolerant-based design.     

基于特征的液压CAD系统产品信息模型研究

结合液压集成块产品模型的建立过程,介绍了特征建模技术中的特征定义、特征分类、特征描述和特征库的建立,建立了面向对象的液压集成块产品特征模型。该模型描述了液压集成块零件设计和制造的有关信息,为ＣＡＤ／ＣＡＭ集成提供了一个统一的产品信息模型。