基于QFORM2D/3D的杯形件冷挤压工艺研究

通过对零件形状及材料性能的分析,运用滑移线场法进行了挤压力计算,制定反挤压和复合挤压2种工艺方案,采用QFORM2D/3D锻造分析软件对2种成形方案进行数值模拟分析,对比这2种成形方案的模拟结果,设计出合理的实验工艺方案,对杯类零件的实际生产具有重要的指导意义。     

包钢某座高炉陶瓷杯侵蚀模型研究

以炉缸埋设的热电偶测量数据为依据, 采用有限元法建立炉缸侵蚀数学模型, 构造带有移动内边界的有限元模型和侵蚀计算流程。由于侵蚀边界的未知性, 计算中必须先假定一个边界, 再根据测温数据来移动边界, 实现循环计算。建立了一种二维有限元搜索内衬侵蚀的自动逼近计算方法, 解决了相关技术难点, 开发了完整的计算程序, 从而实现了高炉炉缸内衬侵蚀的计算由一维技术向二维技术的突破。通过包钢某座高炉在线运行, 侵蚀线和渣铁线的确定, 真实地反映了炉内情况, 为侵蚀模型指导高炉生产奠定了基础。     

旋杯式空调滴水雾化器的研制

介绍了为消除窗式,分体式和柜式空调器滴水现象而研制的旋杯式空调滴水雾化器的结构,工作原理,安装位置及其它特点,认为雾化器不仅可用于空调行业,也可用于喷雾作业。     

300t回转式铜精炼炉盖启闭装置及主要参数计算

介绍了炉盖启闭方式的类型，详细阐述了应用液压控制系统驱动炉盖启闭的原理及其主要参数计算。     

束身衣结构设计及推板方法

对束身衣的结构设计及样板放缩的方法进行探讨,确定束身衣基础样板的结构设计原理和样板放缩的一般规则。考虑到束身衣的塑型作用,在结构设计时采用的材料都是具有高弹性的面料,根据塑型情况在围度尺寸上的取值要比人体实际围度减少10%~20%,同时束身衣的造型与也要配合需要塑型的部位进行不同长度设计。束身衣的放缩是按一定的档差和规律推出其他号型。根据不同体型,可以有杯变身不变和身变杯不变2种形式放缩。束身衣整体放缩时重点考虑是围度的放缩,围度放缩是以4~6 cm为1个档差进行的,其他位置的放缩要按比例分配好放缩量,注意放缩时尺寸的合理性和精确性。     

What can be taught in architectural design? — parti, poché, and felt qualities

This essay begins with a reflection on what has been taught in architectural design since the turn of the twentieth century. I shall trace back to the two disciplinary foundations of the French école des Beaux-Arts – parti and poché – in the education of an architect in the eighteenth and nineteenth centuries. I shall then attempt to superimpose parti and poché on a modern disciplinary framework, say that of mathematics, which leads to musings on a series of architectural problems that include pattern versus type, stability versus mobility, orthogonal versus oblique, confinement versus transparency, and aging versus metallic sheen. These paradoxes, I suggest, demand the education of an architect to address both the instrumental pattern of a building configuration and the ambient felt qualities of a room, rather than vision alone.     

Temperature-dependent Thermodynamic Behaviors of Carbon Fullerene Molecules at Atmospheric Pressure

The study aims at investigating the linear and volumetric thermal expansion coefficients (CTEs) at temperature below the Debye temperature and phase transformation behaviors at atmospheric pressure of carbon fullerenes, i.e., C₆₀, C₇₀ and C₈₀, through a modified Nosé-Hoover (NH) thermostat method incorporated with molecular dynamics (MD) simulation. The calculated results are compared with those obtained from the standard NH and "massive" NHC (MNHC) thermostats and also with the literature experimental and theoretical data. Results show that at temperature below the Debye temperature, the CTEs of the fullerene molecules would significantly decrease with a decreasing temperature and tend to become negative at temperature below 5K. The present results are much more consistent with the literature experimental and theoretical data, in contrast to the other two thermostat algorithms. Besides, it is found that C₆₀ fullerene directly undergoes a solid-vapor phase transformation, instead of a solid-liquid phase transition, implying that the molecule will sublimate when heated rather than melt under atmospheric pressure. This phenomenon is coincident with that of graphite at pressures below 10MPa. The sublimation point of C₆₀ fullerene is about 4350±20K, comparable to that of graphite in the range of about 4000-4500K at pressures below 10 MPa.     

板材零件局部体积成形技术研究

板材局部体积成形技术,或称为板材热冲锻成形技术,为近年来提出的一种板材零件成形方法,其特点是板材冲压成形时不但完成板材零件形状的成形,还兼有局部结构的体积成形,例如局部凸柱、凸台、凸筋等结构的成形,适合于成形镁合金、铝合金等金属的成形,尤其适于替代一些电子器件外壳的铸造加工产品。文章介绍了板材热冲锻成形技术的原理、主要工艺控制参数,并对镁合金盒形件的热冲锻成形过程进行了实验研究和计算机模拟分析。针对带有螺丝柱的典型AZ31B镁合金方盒件,通过实验和有限元模拟,研究了其热冲锻成形工艺。实验表明,在再结晶温度以上冲锻2mm或3mm厚的镁合金板材有很好的成形能力,盒形件的周边和内部凸柱都能同时成形。研究结果表明,合理的模具结构、摩擦润滑条件和加热温度等参数,可以获得侧壁高度均匀、凸柱高度合适、无吸孔和凸柱断裂等缺陷的工件。     

Detecting instrumental icing using automated double anemometry

In this paper, we propose several improvements to the standard double anemometry method for ice detection. In the double anemometry method, the wind speed measurement from a heated reference anemometer is compared with that of an unheated anemometer. A lower measurement from the unheated sensor suggests the presence of ice. First, we propose using a wind speed difference (not a ratio), because anemometers should not deviate significantly at any wind speed under ice‐free conditions. Second, the threshold should vary with ambient temperature to account for cup anemometer slowdown caused by thickening bearing grease. Finally, sensitive thresholds should be used to overdetect ice and false events removed during postprocessing. We created an algorithm to automatically determine the required thresholds and tested it on seven wind turbines during a full winter at a cold climate site. When compared with ice thickness measurements from cameras, the algorithm was equal to or outperformed the manual double anemometry method across all seven turbines.     

Deep drawing of square cups with magnesium alloy AZ31 sheets

The square cup drawing of magnesium alloy AZ31 (aluminum 3%, zinc 1%) sheets was studied by both the experimental approach and the finite element analysis. The mechanical properties of AZ31 sheets at various forming temperatures were first obtained from the tensile tests and the forming limit tests. The test results indicate that AZ31 sheets exhibit poor formability at room temperature, but the formability could be improved significantly at elevated temperatures up to 200 °C. The test results were then employed in the finite element simulations to investigate the effects of process parameters, such as punch and die corner radii, and forming temperature, on the formability of square cup drawing with AZ31 sheets. In order to validate the finite element analysis, the deep drawing of square cups of AZ31 sheets at elevated temperatures was also performed. The experimental data show a good agreement with the simulation results, and the optimal forming temperature, punch radius and die corner radius were then determined for the square cup drawing of AZ31 sheets.