伺服压力机机械负载模拟系统的设计

搭建了整套伺服控制的软硬件系统。为了对伺服压力机的传动系统设计和控制进行优化,构建了一种用伺服电机模拟机械负载动力学特征,以模拟伺服非线性机械负载动力学特征的伺服压力机负载的模拟实验平台。该实验平台采用前馈与转速跟踪结合实施控制,以伺服电机作为可调控柔性负载等效于各种机械负载下的输出,在实验室环境下实现对于各种机械负载的模拟。由于规避了逆动力学特性的引入,本系统具有比以往测功机更好的动态响应特性。     

首钢Q420qENH高性能耐候桥梁钢板的开发

针对传统桥梁钢板强度低,冲击韧性、焊接性能、耐蚀性能差的问题,首钢公司采用低碳成分设计、添加Ni、Cr、Cu耐候元素以及Mo、Nb元素,并优化了轧制和水冷工艺,开发出具有强韧性匹配和良好耐候性的Q420qENH耐候桥梁钢板。对Q420q ENH钢板的显微组织、力学性能进行了检测,同时采用周期浸润加速腐蚀试验对Q420qENH耐候桥梁钢板和Q420qE普通桥梁钢板的腐蚀失重和腐蚀速率进行了对比分析,研究了Q420qENH钢板的锈层形貌及成分。结果表明:Q420qENH耐候桥梁钢板组织为细小的M-A岛粒状贝氏体、准多边形铁素体和针状铁素体的混合组织,具有高强度、低屈强比和良好的低温韧性;其表面生成结构致密的α-FeOOH锈层,能够阻止钢板被进一步腐蚀,因此相同条件下其耐大气腐蚀性能是Q420qE普通桥梁钢板的2倍以上。     

Fretting wear behaviors of a railway axle steel

Fretting damage was one of the most important reasons for the failure of the railway axle. Fretting wear (tangential fretting mode) tests of a railway axle steel (LZ50 steel) flats against 52 100 steel balls were carried out under different normal loads and displacement amplitudes on a hydraulic fretting wear rig. Dynamic analyses in combination with microscopic examinations have been performed. The experimental results showed that the fretting regimes of the LZ50 steel were strongly dependent upon the imposed normal loads and displacement amplitudes. The F_t/F_n curves exhibited different variation trends in different fretting running regimes. The fretting scars presented slight damage in partial slip regime. In mixed fretting regime, the trace of the plowing and plastic deformation flow can be observed on the fretting scars. The wear mechanism during this regime was the combination of the abrasive wear, oxidative wear and delamination accompanied with obvious plastic deformation. The detachment of particles and plowing traces were the main phenomena in slip regime. And, thicker debris layer covered the contact zone of the scar. The severe degradation in slip regime presented the main wear mechanisms of abrasive wear, oxidative wear and delamination.     

黏结性碎煤射流预氧化破黏与流化

具有黏结性（黏结性指数10~30）并高灰的劣质煤,如洗中煤难于适应于现有气化技术,但焦化等行业对这些煤的气化高价值利用具有极大的需求。中国科学院过程工程研究所提出了黏结性煤射流预氧化流化床气化技术,采用含氧气体向流化床气化炉稀相区喷射供料,有效破除煤的黏结性,同时强化气固接触和气化反应,实现对黏结性劣质煤的高效转化。采用小型射流预氧化流化床反应器,研究了黏结性指数为20的一种煤通过射流预氧化的破黏与实现流化的效果。分别考察了射流气过量空气系数（ER）和氧浓度（C_O2）、加热炉设定温度（T）对预氧化破黏及煤颗粒流化的影响效果,分析了反应器内射流区的温度分布与生成气组成随时间的变化规律,并对预氧化后的半焦进行了电镜观测和气化反应活性测试及傅里叶红外分析。结果表明,在流化床中通过射流预氧化有效破黏、实现黏结性煤颗粒流化的工艺条件为：T > 950℃,C_O2=21%,ER > 0.1。在有效破黏的条件下射流区内的温度变化平稳,生成气中H₂与CO含量较低,波动较小,而结焦条件下射流区内温度逐渐下降,生成气中H₂与CO含量增加。经历结焦的半焦表面生成了黏结性物质,而经过预氧化成功破黏后的半焦其表面大部分官能团消失。     

渐开线圆柱齿轮倒棱刀设计

介绍了渐开线圆柱齿轮倒棱刀的设计原理和设计方法,提出了使用CAD软件进行倒棱刀切削仿真的方法,提高了复杂倒棱刀设计效率;介绍了几种特殊的倒棱刀设计方法,解决了有齿端台阶、齿端倒角、变棱边倒棱等特殊要求的产品倒棱刀设计难题。     

航空发动机装配数字化关键技术研究

为了解决航空发动机装配中出现的错装、漏装和装配选择繁琐低效等问题,提出了一套面向装配过程的可视化管理方案,通过在装配工位模拟仿真三维可视化装配场景代替过去必须口传身授的工艺发放形式,避免了错装。利用装配可视化的规程向导,从工作方式上有效避免了原装配过程中出现的漏装。利用遗传算法实现了计算机辅助选择装配,能够更快更合理地帮助装配人员在多组待装配产品中找到最优的装配方案。     

原油管道泄漏监测系统中数据远程传输的设计

介绍原油输送管道泄漏监测／定位系统及其数据传输特点,系统分别利用电话线和网络协议实现了数据的实时传输和批量传输,文章详细描述了各种传输方法的设计过程。     

数控系统中梯形图编辑软件研究及实现

针对目前PLC梯形图编辑软件的缺陷和不足,选用Borland C Builder作为开发语言,采用面向对象的设计方法,开发一种基于Windows 2000面向数控PLC的使用梯形图语言编写PLC程序的通用开发平台。该系统实现了对多种PLC的图形编辑和仿真,使用方便,提高了工作效率。     

复杂运动需求机构自动化选型方法研究

通过引入运动特性变换矩阵,将机构的运动特性,如运动类型、运动轴线和速度特性等,集成于一体,并通过对运动特性变换矩阵行和列进行变换,然后对速度特性进行扩展和分配,实现运动需求的自动分解。该方法从本质上讲是一种自顶向下的求解方法,以成熟的矩阵理论为依托,逻辑性和可操作性强,有利于计算机辅助自动化求解过程的实现。     

The properties of polyurethanes with mixed chain extenders and mixed soft segments

Series of polyurethaneurea elastomers were prepared from 4,4′-diphenylmethane diisocyanate, poly(teuramethylene ether) glycol and poly(hexamethylene carbonate) glycol for mixed soft segments, and 1,4-butanediol and isophoronediamine for mixed chain extenders. Characteristics of the copolymers related with compositions were examined. FT-IR spectra showed that most of the urea carbonyl groups associated in hydrogen bonding, while urethane carbonyls only partially did so. Thermal and mechanical properties were investigated through differential scanning calorimetry and tensile testing. These thermal and mechanical properties are discussed from the viewpoint of microphase domain separation of hard and soft segments. © 1994 John Wiley & Sons, Inc.