共查询到20条相似文献,搜索用时 31 毫秒
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《Mechanical Systems and Signal Processing》2006,20(7):1696-1724
An adaptive method, with which an excitation frequency is continuously varied to obtain maximal oscillation levels, is developed. It is shown that this approach yields the best mechanical efficiency and it is thus essential when the available input power is restricted. The method is demonstrated on a specific apparatus, a squeeze-film levitation device, to obtain maximal levitation height of a floating object. The proposed method uses a minimal amount of frequency dither to revive an identification process that is otherwise singular. With this identified model, the algorithm seeks the best momentary excitation frequency. The algorithm is validated in a simulation and on dedicated experimental apparatus. 相似文献
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此种小径深井救捞装置运用凸轮轨迹控制原理实现托爪(托捞部件)的顺利转起、放下与固定,操作简便,功能可靠,节能环保,是理想的小径深井救捞装置.该装置也可用于矿井、峡谷、墙(楼)缝、冰窟等条件下的救捞. 相似文献
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超声波流量计中反射装置的声-固耦合分析 总被引:2,自引:0,他引:2
对超声波流量计中的反射装置进行有限元模拟计算,利用声-固耦合的方法将流体域内的声压和固体域中的结构变形联系起来。在流体域内求解Helmholtz方程,得到的声压作用于固体表面使得超声波反射装置受到载荷,而结构变形在固体边界的法向上产生结构化加速度。选取一款超声波流量计的反射装置并将其置于无限大空间中,通过一个球体对计算区域进行分割得到有限元计算区域,将超声波换能器简化为垂直入射计算区域的平面波。通过对硬边界、铝材料和不锈钢的模拟结果进行对比,分析3种情况下超声波传播过程中3条路径上的声压级变化,得出固体域的结构变形对超声波传播过程中声压分布产生影响;不锈钢材料宜作为反射装置的材料。 相似文献
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反射装置对超声波流量计水流特性影响的研究 总被引:2,自引:0,他引:2
时差式超声波流量计加装超声波反射装置后对其基表内水流特性影响很大,研究采用标准k-ε模型,计算了采用不同的超声波反射装置和不同的通道结构时,过流通道内的各声路K系数值及标准差值;研究了超声波反射片与管壁间隙的大小对过流通道内水流特性的影响,得到了间隙值与K系数及其标准差值的关系;研究了超声波反射片在中心轴线上的距离对过流通道内水流特性的影响,得到了反射片轴向距离改变与K系数及其标准差的关系;研究了一种新型的渐缩通道结构对超声波流量计过流通道内水流特性的影响.最后,在综合计算结果分析得到最优声道的基础上,计算了该声道不同流量点下的水流特性,给出了K系数分布曲线. 相似文献
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运用两种不同方法设计超声滚压装置中的变幅器,一种采用传统设计法将变幅杆和滚轮分别设计后组装成变幅器;另一种方法是将变幅杆和滚轮整体考虑设计为变幅器.推导出变幅器的频率方程,求出了变幅器设计参数的数值解.通过有限元软件Marc分析,发现传统设计的变幅器中滚轮的设计频率与变幅器的谐振频率误差较大;而整体设计的变幅器的设计频率误差较小.经参数调整后两种变幅器的设计频率都可调至谐振频率20 kHz.由于传统方法设计的变幅器未考虑滚轮作为负载对变幅杆的影响,在实际应用未能达到超声系统良好的共振效果;而整体设计变幅器中变幅杆及滚轮尺寸小,对变幅器的谐振频率影响较小,结构紧凑,抗弯刚度好,通过有限元分析验证了变幅器的整体设计理论完全可行,能够达到良好的共振效果. 相似文献
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李威 《工业仪表与自动化装置》2002,(1):60-63
介绍了一种远程设备控制系统故障报警装置的系统组成,系统的软、硬件设计。该装置可利用电话进行设备的故障报警,可广泛应用于微机控制的设备中,并且可以推广到采用电话进行遥控的设备中去。 相似文献
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Md. Alim Iftekhar Rasel Heuy-Dong Kim 《Journal of Mechanical Science and Technology》2013,27(10):3103-3112
In recent times, a unique drug delivery system known as transdermal drug delivery has been developed which can deliver drug to the human skin without using any external needle. A shock tube system is used to generate a moving shock wave which flows through the tube. The idea is to accelerate particles behind the moving shock so that it can attain sufficient momentum to penetrate the outer layer of the skin (stratum corneum) and have a pharmaceutical effect. The important issue while delivering drug to the skin is to deliver it with uniform velocity and spatial distribution. Among different tried and tested systems the contoured shock tube (CST) seems to fulfill this requirement successfully. This paper focuses on numerically investigating the flow field and analyzing the gas and particle interaction through the contoured shock tube. Computational fluid dynamics (CFD) has been used to simulate and further analyze the flow field. The important issues regarding the flow field and the gas particle interaction are discussed in details. 相似文献
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为解决确定性侧向位移分离装置(DLD)数值模拟的精度以及其颗粒分离规律等问题,将直接力虚拟区域法应用到刚性颗粒在DLD中的运动直接数值模拟中.开展了DLD装置的侧向边界条件的影响分析,建立了侧向边界条件与DLD内部流场倾斜角度之间的关系,提出了对于模拟侧向圆柱数量较多的实际DLD装置应该采用周期性边界条件;在流场特征和刚性颗粒分离半径上对所采用的数值模拟方法和侧向边界条件进行了评估和实验.研究结果表明,对于侧向有较多数量圆柱的实际DLD装置,采用较少数量的圆柱和周期性边界条件来减少计算量,可以保证数值模拟的精度. 相似文献
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为了解决化学工业反应釜清洗工况的安全生产问题,研制了清洗头实时监测系统。针对国外原方案中传感器容易挂料且难以清理的缺点,采用加速度传感器监测釜体表面振动信号,通过信号的相关分析,实时监测清洗头工作情况,解决了传感器挂料对监测可靠性的影响。在信号传输中采用无线信号模块代替原有有线电缆的连接,减少了复杂工业现场的连线成本,提高了可靠性。 相似文献
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Ductility improvement of aluminum 1050A rolled sheet by a newly designed ball burnishing tool device 总被引:1,自引:1,他引:0
Fathi Gharbi Salem Sghaier Hedi Hamdi Tarek Benameur 《The International Journal of Advanced Manufacturing Technology》2012,60(1-4):87-99
Conventional ball burnishing processes using a roller or a ball pressed against round or small flat surfaces have long been used to improve hardness, fatigue strength, and wear resistance of mechanical parts by plastic deformation. However, the treatment of large flat surfaces using conventional techniques is rarely considered because of its time consumption. In the present work, the optimal burnishing parameters of rolled sheets of aluminum 1050A are determined by means of a newly developed burnishing tool device especially designed to treat large flat surfaces with orders of magnitude reduction in burnishing time. Experiments were designed and performed on a machining center based on response surface methodology with central composite design. The burnished specimens were then tested to find the burnishing condition under which ductility was improved. This study has resulted in significant new insights into the effect of burnishing on the surface quality and workpiece properties of aluminum 1050A plates. A second-order mathematical model, validated using data obtained from atomic force microscopy, was developed to predict the surface roughness as functions of speed, force, and feed rate. The results indicate that burnishing of aluminum 1050A plates improves its ductility, but not its micro-hardness. Following the various burnishing conditions, the micro-hardness measurements range from 40 to 43?HV (50?g), indicating that there is little or no hardening. Although a moderate effect with varied degrees is found on the surface roughness as functions of the investigated parameters, the burnishing force has a significant effect on ductility. The results also indicate that lower values of roughness do not guarantee better ductility for aluminum 1050A plates. Furthermore, the effect of the burnishing loads on the residual stresses was found to depend on the feed direction. 相似文献