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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。 相似文献
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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。 相似文献
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基于元结构的机床床身结构性能分析与优化设计 总被引:1,自引:0,他引:1
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. 相似文献
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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。 相似文献
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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. 相似文献
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基于夹具的工件自由度约束分析模型 总被引:1,自引:0,他引:1
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. 相似文献
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微钻法进行岩石可钻性分级 总被引:2,自引:0,他引:2
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。 相似文献
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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. 相似文献
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Effect of electroosmotic flow of aqueous suspension of nanosilica on the properties of carbonated concrete
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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. 相似文献
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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. 相似文献
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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。 相似文献
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球墨铸铁曲轴应用前景的评估 总被引:4,自引:3,他引:4
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。 相似文献
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《中国有色金属学会会刊》2020,30(8):2265-2273
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. 相似文献