三厢车顶盖流水槽工艺分析与模具设计

通过对三厢车顶盖的冲压工艺方案进行分析,介绍了三厢车顶盖尾部流水槽的多种成形工艺方案以及各方案具体的模具结构与工作原理,通过对工艺方案进行分析对比,找出最优方案,以提高加工及生产效率。     

基于MoldFlow的塑料非球面透镜注压模浇注系统设计

为了给塑料非球面透镜注射压缩模具设计提供理论依据,设计了8种塑料非球面透镜注压模浇注系统方案。应用MoldFlow模拟软件对这8种浇注系统方案进行了注射压缩流动分析研究,并且通过对这8种浇注系统方案的模拟结果进行分析比较确定了最优设计方案。     

基于元结构的机床床身结构性能分析与优化设计

以CA6150车床床身的结构分析为例,首先对床身受力情况进行分析并运用ANSYS软件进行结构静刚度和模态分析,在此基础上运用元结构对床身的筋板结构进行优化.在床身基本尺寸不变的前提下,以床身结构固有频率为优化目标,提出该床身结构若干改进方案,并通过对各种方案分析比较确定结构最优方案.     

Z形梁冲压回弹畸变的形成机理研究及控制

采用冲压成形分析软件Dynaform对汽车Z形梁类零件的成形过程和回弹进行了有限元模拟分析,研究了分析结果中各截面应变不均的问题,得到了应变不均的分布曲线。分析了传统方案的特点,提出了改进方案,并对改进方案的应变分布进行了分析。曲线显示压料面与梁的法兰边高度差越大,应变分布不均严重。并对新方案的关键变量进行了分析,找到回弹值最均匀的方案,同时单个截面的最大回弹值减少到1°以内。最终按此优化的型面加工模具,并成功获得了合格产品。     

异型电机壳体拉伸工艺分析及数值模拟

利用传统方法对异型电机壳体拉伸成形工艺进行分析和计算,制定拉伸工艺方案,并用数值模拟技术进行模拟和分析,得出合理的工艺方案和参数。     

冷连轧机架铸造工艺及组织性能浅析

以鞍钢1780冷连轧机架为例,通过运用Solidworks三维绘图软件对机架的质量特性进行分析;使用唯科公司的GTA铸造工艺设计软件,对铸件的各个部分进行模数计算,对冒口补缩距离、冒口尺寸参数、外冷铁尺寸及个数、浇注系统等进行分析计算;使用华铸CAE软件将设计完成的铸造工艺方案进行数值模拟分析,根据模拟的结果,对铸造工艺方案进行调整,使机架工艺方案更加合理.     

基于AutoForm R7对顶盖后部外板成形性进行分析及回弹补偿研究

通过分析零件的形状及结构特点,确定零件的成形工艺方案,利用AutoForm R7对零件进行拉深成形性分析,确定拉深方向、拉深筋类型、成形力和压边力,再进行零件回弹分析,确定回弹工序及回弹补偿方案,根据分析回弹数值进行补偿,再次进行回弹分析,以达到预期效果。AutoForm R7成形性分析及回弹分析的准确性得到了现场验证,对类似零件的工艺方案及回弹补偿方案有一定参考价值。     

某风洞两缸同步液压开环控制系统分析与改进

对国内某风洞两缸同步液压开环控制系统存在的问题进行分析,通过对比几种液压同步方案的特点,最终采用同步马达再合理配置单向调速阀进行流量补偿构建开环同步回路的方案。对改进方案的原理进行了详细阐述,分析调试过程中注意事项。该改进方案最后取得了良好的应用效果,为有类似需求的系统提供了借鉴。     

基于CAE分析某车型中通道前延伸板的制造成本

针对某企业冲压降本的需求,借助AutoForm软件对其中通道前延伸板进行冲压成本分析,分析2种工艺方案的制造成本,结合车型的产量对其综合成本进行对比,得出制造成本更低的冲压工艺方案,以指导后期工艺制订和模具方案的设计。     

铸造模拟技术在消失模铸造工艺开发中的应用

通过对某拖拉机传动箱壳体结构及消失模铸造工艺性分析,设计了三种消失模铸造工艺方案,通过模拟仿真分析各个方案的优劣性,根据模拟结果选择最优方案,并对工艺进行优化.有针对性的进行工艺实验,减少实验次数,降低了实验成本,缩短了工艺开发周期.     

基于夹具的工件自由度约束分析模型

夹具设计最主要的目的就是将工件精确定位.在定位过程中,工件自由度必须首先合理地受到约束以确定工件相对于刀具的正确位置.因此,分析工件的自由度约束情况是复杂定位方案设计甚至整个夹具设计的关键所在.本文基于刚体运动学,建立了分析工件自由度约束情况的定位原理数学模型,从而使得传统的定位原理从定性描述上升为数学定量表示,并为计算机辅助夹具设计系统的开发提供了基础理论.另一方面,以定位原理数学模型为基础,在UG软件系统环境下实现了夹具约束工件自由度分析系统的二次开发.     

微钻法进行岩石可钻性分级

本文在分析现有典型岩石可钻性分级方法不足之处的基础上，提出了选择微钻法来研究金刚石钻进钻石可钻性的观点，阐述了微钻法需要解决的问题，同时确定选择综合参数W值来衡量石可钻性，通过室内微钻实验验证这种方法的可行性。     

Evaluation of the quality of the components of the process of manual arc welding using entropy methods

This paper examines important technical issues pertaining to the methodological limitations of the welding techniques currently in use, with particular consideration given to welding mathematical modelling procedures. The recent progress achieved with high nano-technologies suggests the application of similar approaches to conventional mechanics and materials science, with particular reference to welding processes. Recent studies on welded joints have highlighted the benefits to be derived from ‘Industrial Applications of Neutron Techniques’ giving access to fundamental information – not obtainable using other methods – for improving quality and durability. ‘Small angle neutron scattering’ and ‘determination of residual stress by neutron diffraction’ make it possible to characterize materials at the atomic and nanoscale level, offering existing technologies the essential contribution of precise structural methods. This paper describes the fundamental theoretical aspects of both techniques, along with several welding studies conducted using ‘small angle neutron scatter’. An experimental programme has recently been devised by Rogante Engineering, in collaboration with the Budapest Research Reactor, to develop welding processes aimed at improving safety, quality control, and durability control for the joints under consideration.     

论创新性学习机制的建立

本文结合学习观念在学习时空、态度、动机、指向、内容与方法等六个方面的实质性转变，论述了如何建立创新性学习机制。     

Effect of electroosmotic flow of aqueous suspension of nanosilica on the properties of carbonated concrete

The paper investigates the possibility to use electroosmosis to transport nanosilica (NS) particles inside carbonated concrete, in order to exert a filler effect and enhance its durability performance. This method aims to extending possible beneficial effects of NS to existing reinforced concrete structures, where the presence of a carbonated layer of concrete is very likely. Injection tests were performed with electrochemical cells on carbonated concrete discs with water/cement (w/c) ratios of 0.50, 0.55 and 0.65, using a NS aqueous suspension at the anode. The results indicated that a flow did occur through the concrete disc and it was directed from the anode towards the cathode. A linear relationship between flux and applied voltage gradient was obtained, which is typical of electroosmotic phenomena. The bulk properties of concrete, such as density, water absorption and sorptivity, were not affected by the injection tests, whilst electrical resistivity increased indicating a mild ‘sealing’ effect on the surface. Also microstructural analyses highlighted the local presence of NS that decreased the local porosity close to the surface.     

Comparison of the effects of small additions of silicon or aluminum on the oxidation of iron-chromium alloys

A study has been undertaken of the oxidation behavior of Fe-26 wt.% Cr-1 wt.% Al and Fe-26 wt.% Cr-1 wt.% Si at 800° and 1000°C in oxygen, in order to determine the usefulness of the two tertiary elements in facilitating the development of the Cr₂O₃ external scale. The research has also permitted a comparison of the modes of internal oxidation of these elements, with a view to ascertaining the ease of establishment of the tertiary element oxides as healing layers at the scale/alloy interface. It has been shown that aluminum is the more effective addition in this respect, due to formation of a higher population density of internal oxide nuclei in the early stages. However, in the 1% Al alloy, the precipitates penetrate inward, to considerable depths, as continuous platelets, making development of a complete healing layer difficult. In practice, a higher aluminum concentration is necessary for the closely spaced precipitates to coalesce to form the healing layer, but the process then occurs rapidly. The initial internal oxide nuclei in the 1% Si alloy have a much smaller population density and are restricted to a location very close to the surface. Thus, a healing layer can be established, but the large interparticle spacing makes this a very slow process. Even at a higher silicon concentration, it takes a significant period to be completed. The effects are discussed and accounted for, particularly in terms of the relative stabilities of the various oxides.     

影响泛昔洛韦片治疗带状疱疹疗效的因素分析

目的: 分析影响泛昔洛韦片治疗带状疱疹疗效的因素。方法: 泛昔洛韦片 250 mg, 每天 3 次、用药 7 d 治疗带状疱疹;logistic 回归分析影响因素。结果: 年龄、丘疱疹/水疱数目、新水疱停止出现时间、疼痛消失时间、开始脱痂时间、全部脱痂时间、有可疑诱因和治疗前总积分与痊愈率、有效率呈负相关,是影响痊愈率、有效率的重要因素;而性别、病灶部位、糜烂数目或面积、红斑、疼痛程度, 对疗效无明显影响。结论: 年龄、丘疱疹/水疱数目、新水疱停止出现时间、疼痛消失时间、开始脱痂时间、全部脱痂时间、有可疑诱因和治疗前总积分与痊愈率、有效率呈负相关, 是影响泛昔洛韦疗效的重要因素。     

BGA焊接技术的探讨

随着1C技术的不断进步,IC正在向着集成化、小型化、高性能、多管脚的方向发展,BGA封装形式在IC技术的发展中得到了广泛地应用,因此BGA封装的焊接技术越来越受到重视.本文主要根据BGA封装在回流焊接中出现的短路、虚焊、空洞、溅锡等现象,分别从PCB焊盘设计、器件保护、钎料选择及回流焊温度曲线的确定等方面进行了分析,并...     

球墨铸铁曲轴应用前景的评估

目前球铁曲轴应用中存在的主要问题是疲劳强度满足不了发动机爆发压力不断提高的要求，以及球铁质量不够稳定。提出了以疲劳强度为核心对曲轴质量进行评估，并通过抗拉强度与伸长率的合理匹配、使用等温淬火、圆角滚压等措施提高球铁曲轴的疲劳强度。为提高球铁曲轴质量可靠性，建议：(1)限定铁液中有害元素的含量；(2)控制原材料质量，并采用感应炉熔炼；(3)对原铁液脱硫，降低其硫量；(4)改进球化、孕育工艺；(5)采用先进检测仪器，提高在线检测水平；(6)重视疲劳性能测试，寻求适合于曲轴的检测方法；(7)开展球铁曲轴强度评价的研究。     

Kinetics of carbothermic reduction of marmatite in presence of lime

The direct carbothermic reduction of marmatite in the presence of lime was studied by thermogravimetric method to determine the technical feasibility to produce Zn(g) without polluting with SO₂(g). X-ray diffraction analysis of partially reacted samples indicated that the reduction occurred through the formation of ZnCaOS and Ca₂Fe₂O₅ as intermediate products to yield Zn(g), and solid Fe and CaS as the final products. Temperature had the major effect on the rate of reduction. Complete conversion of marmatite was obtained at 1100 °C in about 10 min using 300 mg samples with molar ratio of (Zn, Fe)S:CaO:C equal to 1:1:1. The kinetics of the overall reduction reaction was analyzed by the model ln(1−X)=−kt, which represented the data well up to a fractional conversion of 0.95 in the temperature range of 1000−1150 °C. The determined activation energy in this temperature range was 257 kJ/mol. The results demonstrated the technical feasibility to produce Zn(g) by this method without producing noxious SO₂(g) emissions.