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以某型铸造型液力变矩器为研究对象,对比其重力铸造和低压铸造两种常用铸造方式的成型质量。应用铸造工艺仿真软件ProCAST进行了充液和凝固过程的仿真及铸造缺陷的评估及对比分析。在此基础上,将预测的缺陷与实际浇铸产品射线无损探伤结果进行对比验证。结果表明,相比于重力铸造,低压铸造可以通过调整压力实现对液流充型过程的控制,使得充型平稳、顺序凝固、补缩动力增强,提高液力变矩器的力学性能。实际浇铸及探伤结果表明,铸造仿真可以较好地预测缺陷种类及分布,为铸造工艺改进提供有效指导。 相似文献
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本文基于Anycasting软件对球墨铸铁汽车泵体的浇注系统进行数值模拟,侧重分析了铸件充型、凝固过程中温度、压力以及速度场的变化规律。最后由模拟结果来预测该零件可能产生的铸造缺陷,进一步提出改进方案,本文的研究可为实际铸造生产中浇注系统的设计与优化提供理论依据,有助于提高铸件的铸造质量。 相似文献
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针对铝合金薄壁壳体铸造成型高质量要求,通过向ZL101A铝合金中增添Al-10Sr变质剂以及微量Ni元素,制备铝硅基精铸材料坯件,借助加热设备与SCC-44500电子万能试验机对铝硅基精铸材料进行高温压缩试验,得到不同应变率与不同温度下材料的应力-应变曲线,发现铝硅基精铸材料在各应变率及温度下的屈服强度相对ZL101A铝合金均提高。以铝硅基精铸材料进行液压泵薄壁壳体铸造工艺设计分析,基于ProCAST铸造模拟软件,采用低压铸造工艺方案对铝合金薄壁壳体低压铸造过程进行多尺度模拟,分析预测得到了温度场和流动场对铸件充型和凝固过程中缩孔缩松形成的影响,并对壳体铸件的显微组织特征进行了分析,观察得到内部二次枝晶臂间距和共晶层片间距分布状态,综合分析宏微观结果可知,适合的铸造工艺可以制备出完整高性能的铝硅基合金薄壁壳体铸件。 相似文献
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采用Flow-3D软件建立了ADC12铝合金车门内板挤压铸造过程的有限元模型,探讨了模具温度、浇注温度和压机下压速度对熔体充型状态的影响,对挤压铸造工艺进行了优化,并进行了试验验证。结果表明:浇注温度高于953K,充型结束时低于固相线温度的区域逐渐减小;模具温度会影响铸件充型边缘区域的温度;高速下压会产生过多的气孔、氧化渣夹杂,不利于铸件顺序凝固;当浇注温度不低于953K,模具温度不低于583K,压机下压速度为24mm·s-1时,可以成功制备结构完整的铝合金车门内板铸件;试验结果证明了模拟结果的正确性。 相似文献
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考虑驱动力矩、重力、哥氏力、运动阻力和惯性耦合力,根据考虑横向弯曲变形的Euler-Bemoulli细梁模型,并考虑离心力作用下的拉伸变形,建立回转运动梁的动力学模型。将梁根部的回转角度分解为整体刚性运动回转角度和刚体运动和柔性运动激发刚柔耦合回转角。将梁的柔性振动位移也分解为由整体刚性回转角所激发的动力激励振动和刚柔耦合回转角运动及刚柔耦合项共同激发的刚柔耦合振动。整体刚性回转角和动力激励振动,通过数值方法(如龙格-库塔法)求解,而将刚柔耦合回转角和刚柔耦合振动,通过奇异摄动法求解。通过数值方法和奇异摄动法相结合的方法,能够正确计算刚柔耦合回转角及其对梁振动位移的影响,更精确、深入地分析回转梁的动力学特性。 相似文献
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As a new global numerical approximate technique, the generalized differential quadrature (GDQ) method is used in this paper to study the influence of initial pressure load on the free vibration of a rotating thin isotropic truncated circular conical shell. The present motion governing equations include the influence of initial stress field due to the initial uniform pressure. The effects of initial hoop tension and the centrifugal and coriolis accelerations due to rotation are also considered. The influence of initial pressure on the frequency characteristics of the rotating conical shell is discussed in detail. For the examination of present work, frequency numerical comparisons are made with those available in published works, and very good agreement is achieved. 相似文献
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By using the generalized differential quadrature (GDQ) method, this paper presents the orthotropic influence of composite materials on frequency characteristics for a rotating thin truncated circular symmetrical cross-ply laminated composite conical shell with different boundary conditions. The present governing equations of free vibration include the effects of initial hoop tension and the centrifugal and Coriolis accelerations due to rotation. Frequency characteristics are obtained to study in detail the orthotropic influences. Effects of boundary condition, rotating speed, circumferential wave number and geometric property are also discussed. To ensure the accuracy of the present results by the GDQ method, comparisons are made with those available in open literature and very good agreements are achieved. 相似文献
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ZHU Xiaocheng GUO Qiang DU Zhaohui CHEN Hua ZHAO Yan 《机械工程学报(英文版)》2008,21(3):76-83
Unsteady flows and rotating stall of a low-speed centrifugal compressor are investigated by measuring vaneless diffuser wall static pressure fluctuation and internal flow fields at different small flow fluxes. During the experiment, firstly the real time static pressure fluctuations on the vaneless diffuser shroud at different circumferential and radial position were acquired by high-frequency dynamic pressure transducers. Discrete Fourier transformation analysis and cross-correlation analysis were applied to the experimental results to ascertain the rotating stall beginning operation conditions and stall cells numbers and rotating speed. Secondly, the vaneless diffuser inlet flow angle distribution along diffuser width direction was acquired by single hotwire, which was compared with SENOO's analysis results. At last, the internal flow fields of the centrifugal compressor were investigated with a particle image velocimetry (PIV) system at different small flow fluxes. The flow field development of vaneless diffuser and blade flow passage are given at rotating stall conditions. The experiments enrich the understanding of rotating stall flow phenomenon of the low-speed centrifugal compressor and provide full experiment data for designing high performance centrifugal compressor. 相似文献
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A high-speed rotation instrument to produce centrifugal fields greater than 100 million times gravity has been constructed. Small, solid, spherical high-carbon chromium steel rotors are suspended magnetically in high vacuum and spun by a rotating magnetic field. It is found that the spinning rotor explodes when the calculated average value of stress in the meridian plane reaches about 1.2 times the tensile strength of the material. The maximum speed of rotation so far achieved for more than a few days without bursting was obtained with a rotor of 1.50 mm diameter. The speed of 2.11 x 10(5) rev/s corresponded to a centrifugal field of 1.34 x 10(8) times gravity. Our instrument will find application in the study of nuclear atomic phenomena. 相似文献