铝液对铸轧辊辊套表面裂纹形成及扩展的影响

用OM、SEM及能谱仪对辊套表面裂纹和试件断口形貌进行了观察,并采用X-ray衍射仪对裂纹中铝的化合物进行了分析。结果表明,辊套表面裂纹起源于机械加工产生的微缺陷,表面裂纹方向与切削痕迹方向相同;而铝液是从表面裂纹形核处沿开裂面挤入裂缝中;在裂纹尖端没有发现铁铝化合物;高温铝液对辊套表面裂纹形成及扩展影响不大。     

基于合体两片袖的内旋造型结构设计

为探究袖身内旋造型的形成机制及影响因素,增强合体两片袖的活动性和机能性,从立裁角度提出分割线借量法、袖中线偏移法与袖中线旋转法3种结构设计方法。借助三维虚拟试衣技术进行单变量试验设计,确定每种方法中各变量的取值范围;通过正交试验设计,完成16款袖子的结构设计、虚拟试衣及实样制作;最后建立评价体系,进行主客观评价与分析。结果表明：各变量对内旋夹角影响程度的大小依次为袖中线旋转量、分割线借量、袖中线偏移量;结合动静态指标、主客观评价数据,得到的美观与舒适俱佳的袖子变量组合为分割线借量0.5 cm,袖中线偏移量2 cm,袖中线旋转量1 cm。     

基于疲劳强度的铰链梁结构优化设计研究

以有限元法作为结构分析手段,建立金刚石六面顶压机的关键零部件——铰链梁的有限元力学模型和结构优化设计模型,在考虑疲劳强度的条什下,完成铰链梁的结构优化设计,为金刚石六面顶压机关键零部件的设计提供一套较为完整的设计方法和设计系统。同时,针对饺链梁的具体情况和特点,采用IGES数据交换标准,实现实体建模软件Pro／E和有限元分析软件ANSYS之间的有效数据交换,形成一个较为有效、完整的铰链梁CAD（computer aided design）／CAE（computer aided engineering）集成设计系统,为CAD（computer aided design）／CAE（computer aided engineering）／CAM（computer aided manufacture）系统集成研究提供有益的尝试。利用ANSYS的APDL参数化语言,编制铰链粱的结构优化设计程序ODPST,采用零阶优化方法进行铰链梁的结构优化设计,得到精确可靠的设计参数,有效提高铰链梁的抗疲劳性能和强度。     

6061-T6铝合金中厚板-节点套多层多道焊数值模拟

为研究铝合金中厚板-节点套接头在多层多道焊后的残余应力和变形分布,本文基于ABAQUS软件建立了该接头三维有限元模型,采用双椭球热源、生死单元法以及顺序耦合法,对6061-T6铝合金中厚板-节点套多层多道焊进行数值模拟,并分析了接头的温度场,以及在夹具约束下的焊接残余应力及变形的分布情况。研究结果表明:数值模拟与实际接头的熔池形状吻合度较高;摆动焊接过程中温度曲线呈多峰结构;焊件的升温速率明显大于冷却速率,且冷却速率随时间逐渐减小;焊接残余应力主要集中在焊缝及夹具区域,且小于6061-T6铝合金在室温下的屈服强度;接头的最大横向残余应力为129.9 MPa,中厚板上的横向残余应力大于节点套上的横向残余应力;接头的最大纵向残余应力为132.9 MPa,沿焊接方向,焊缝处的纵向残余应力呈山峰状分布;该接头在Y轴方向上的变形最大,为1.494 mm,该接头的最终变形结果为上凸变形。     

一种改进型套筒单极子天线的研究

文中基于单极粗振子展宽带宽理论,采用一种新型加粗套筒单极子辐射体的实用模型来展宽套筒单极子天线的阻抗带宽,并利用有限元法(FEM)对其驻波和辐射特性以及天线各参数进行了分析。在此基础上,设计了一副工作在108MHz～420MHz频段、电压驻波比小于3．0的实用套筒单极子天线,计算结果与实测结果吻合良好。     

Some contraindications of hole expansion in riveted joints

Comparable fatigue tests were carried out on aluminium alloy 7475-T7351 double butt joints with untreated and with cold expanded holes. Surprisingly, the behaviour of the specimens having cold expanded holes was worse than that of specimens with untreated holes. This result was attributed to the surface upset which was present in cold expanded holes. Several hypotheses were formulated and experimentally verified to overcome this problem, such as deeper hole deburring, rivet diameter, joint design and grip material, steel instead of aluminium alloy.Additional tests demonstrated that the problem was not present in sealed joint as the surface upset was hidden in the sealant thickness. Sealants have detrimental effects in the fatigue resistance of riveted joints, as they increase the load transferred by rivet bearing. The hole expansion is beneficial in this condition, while in un-sealed joints its effect must be accurately evaluated.Other authors too highlighted possible problems due to surface upset, up to suggest to eliminate it. Only in a very few cases, a reduction of fatigue life as a consequence of hole expansion was observed.     

提高500TPD环形套筒窑设备运转率的措施

文章介绍了500t/d套筒窑工艺及设备改造。通过稳定操作制度、完善设备管理制度,套筒窑故障率明显下降,设备运转率提高,热工制度稳定,提高了各窑产能,避免骤冷骤热,延长耐材的使用寿命,达到稳定活性石灰质量的目的。     

高压取样器的研究与应用

针对钟控、电控取样器下井前要预设时间，操作繁琐，油水界面难以掌握，取样成功率低，在高凝油、稠油井重量轻无法用钢丝投送取样，研制了不用时间控制，通过上提下放钢丝绳控制，取样器在井下重复开启和关闭的摩擦式取样器和随管柱下入不怕遏阻，在坐封和解封封隔器的操作中控制取样器开启和关闭的滑套式取样器，并设计了相关取样工艺，解决油田高压物性取样难题。     

Proposals towards improving worsted processing. Part 1: identification and theoretical evaluation of possibilities for optimising the drawing sequence

The possibility of improving the evenness of worsted slivers, rovings and yarns by the simple expedient of optimising the drawing sequence is examined theoretically. The drawing sequences commonly used by mills have generally been established by trial-and-error methods, using the knowledge that the evenness of any material can be contained or improved by the practice of doubling, and made worse by drafting, but with little or no application of scientific method. A simple mathematical model of the worsted processing sequence, which has proved to be a powerful tool for both problem solving and in research, is used to investigate if and how yarn quality might be improved by simple adjustments to the number of doublings and the draft ratios used. The outcome of these theoretical studies predicts that some improvement in the quality (evenness) of yarn can be achieved, and raises questions about the appropriateness of the doublings and the draft ratios commonly used.     

全套管薄壁灌注桩在山区某工程基坑支护中的应用

结合工程施工实例,介绍了全套管薄壁灌注桩的施工工艺流程、关键工序的主要事项,并与其它大直径灌注桩进行对比,说明该桩型作为基坑支护的围护桩具有较大的经济社会效益和广阔的市场前景,同时也对存在的问题做了总结。