共查询到20条相似文献,搜索用时 171 毫秒
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介绍了挖掘机、卷扬机缠绕钢丝绳的卷筒圆弧形螺旋槽、环槽的一种新的加工方法的原理及仿形轮的设计。这种加工方法采用微机控制技术和液压菜技术相结合对普通车床进行改造,实现自动加工。 相似文献
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介绍了直角形滑环组合密封的组成、结构材质、配合、压缩量的确定,阐述了其密封机理,分析了其密封结构的特点及使用范围,介绍了安装工艺过程.经生产实践证明,直角形滑环组合密封在高压高温下的密封效果优于其他组合密封装置. 相似文献
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徐汝 《机械制造与自动化》2012,41(4):35-38
仿形系统是龙门往复式全自动洗车机的重要组成部分,也是整套设备技术水平的核心,直接关系到洗车设备最终的使用效果及安全性.介绍了仿形刷洗系统的结构原理和控制方法.硬件设计采用PLC可编程序控制器;通过模拟量输入模块的应用,简化了刷洗部分传统的仿形控制,节约了大量的制造成本,同时大幅提升了控制系统运行的可靠性和安全性. 相似文献
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浅盒形件超塑胀形工艺理想加压曲线的研究 总被引:4,自引:1,他引:3
通过对浅盒形件横截面的应力、应变及应变速率的分析,推导出了使危险点应变速率为恒定最佳值时的理想加压规律。试验结果表明:用该加压曲线进行加载,能有效地提高成形极限,改善厚度分布均匀程度。 相似文献
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超塑拉伸变形的力学解析 总被引:1,自引:0,他引:1
以作者在超塑性拉伸变形力学解析理论所做的一些工作为主,较为系统地回答了在该分支存在的一些涉及到变形规律力学本质的疑问,重点介绍应变速率敏感性指数m值和应变硬化指数n值的测量方法,并结合典型变形路径,精细分析了变形路径对n值和m值的影响,对变参数超塑拉伸变形本构方程进行介绍,最后是作者关于超塑性研究中值得注意的一些问题的意见。 相似文献
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《Journal of Mechanical Working Technology》1987,14(2):159-172
Some particular metal alloys offer excellent stability of deformation, this property being termed superplasticity. In the aeronautical industry, superplastic forming associated with diffusion-bonding techniques allows the manufacturing of complex shapes in one operation. The purpose of this paper is to contribute to a better knowledge of the influence of parameters such as bulging pressure vs. time, lubricant, die geometry, etc. The superplastic forming of a Ti6Al4V alloy sheet at 927°C into a long, rectangular box-section has been studied. Sticking contact and Coulomb friction have been considered. The model presented here will be used to choose parameters — such as the friction coefficient — to be introduced subsequently into a more sophisticated model, such as one employing the three-dimensional finite-element method. 相似文献
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This paper describes the development of a rigid viscoplastic finite element formulation for analysing the gas-pressure constrained bulging processes of superplastic circular sheets in cone disk shape dies. In this formulation, the effects of strain hardening and strain-rate sensitivity of materials are included, and the boundary friction condition is introduced into the formulation in the form of friction functional. The finiteelement model based on the membrane theory is developed, and then applied to simulate superplastic constrained bulging processes. The solutions by the rigid viscoplastic finite element method are compared with existing experimental data. The influences of the geometrical parameters of the dies, the friction factor in the friction functional, the strain hardening and the strain-rate sensitivity on the inhomogeneity of thickness distribution are studied in detail. 相似文献
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板料超塑胀形过程仿真及其应用 总被引:3,自引:0,他引:3
板料超塑胀形通常需要高温密闭环境,测试分析困难。本文在刚粘塑性有限元法的基础上开发了超塑胀形计算机仿真系统。应用仿真系统可对材料变形过程进行动态仿真,预测成形件壁厚分布,优化确定成形压力 时间曲线,为成形工艺设计提供有效分析工具。文中给出了“碗”形零件气压胀形仿真实例。 相似文献
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本文从连续介质塑性力学的基本理论出发,并应用变m值超塑性本构方程,求得超塑恒压自由胀形高度极限系数D和恒压胀形充填型槽半径极限系数D',进而给出用D和D'对应地确定极限高度和极限半径的简便方法。由于理论与实验结果符合,故可把D和D'作为超塑胀形的重要工艺参数。 相似文献
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Joon-Tae Yoo Jong-Hoon Yoon Ho-Sung Lee Sung-Kie Youn 《Journal of Mechanical Science and Technology》2012,26(7):2101-2105
Macroscopic superplastic behavior of metallic or non metallic materials is usually represented by the strain-rate sensitivity, and it can be determined by tensile tests in uniaxial stress state and bulging tests in multi axial stress state, which is the actual hot forming process. And macroscopic behavior of Non-SPF grade materials could be described in a similar way as that of superplastic materials, including strain hardening, cavity and so on. In this study, the material characterization of non-SPF grade Inconel 718 has been carried out to determine the material parameters for flow stress throughout free bulging test under constant temperature. The measured height of bulged plate during the test was used for estimation of strain-rate sensitivity, strain-hardening index and cavity volume fraction with the help of numerical analysis. The bulged height obtained from the simulation showed good agreement with the experimental findings. The effects of strain-hardening and cavity volume fraction factor for flow stress were also compared. 相似文献