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应用海水热泵系统存在的问题及解决措施 总被引:6,自引:0,他引:6
论述了海水热泵取、排水口置及管道敷设、海水的腐蚀性、冬季海水温度过低等问题对应用海水热泵的影响,探讨了解决问题的主要措施,提出了适合海水热泵的冷凝器(夏)或蒸发器(冬)型式。 相似文献
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空铁作为新型交通方式得到了迅速发展,为实现空铁线路中Y形立柱金属结构的轻量化设计,对线路中的Y形立柱进行了参数化建模,并充分考虑其结构刚度、强度及支腿稳定性对线路安全性的影响,利用ANSYS有限元分析软件分别运用零阶优化方法与多层优化设计方法对Y形立柱金属结构进行优化设计。由优化结果可知,在满足设计要求下,与优化前相比采用零阶优化方法与多层优化设计方法的金属结构重量分别减轻了11.3%和13.8%,在支腿稳定性校核中分别降低了12.1%和24.4%,使结构更加趋于安全。综上所述,多层优化设计方法更适合对Y型立柱进行优化,基本满足降低金属结构重量,提高支腿稳定性的要求。 相似文献
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采用有限元分析软件ANSYS研究20 t挖掘机铲斗油缸用Y形圈在一个往复运动周期内、不同热源作用下的温度分布;采用控制变量法分析各因素(介质压力、往复运动速度、介质温度等)对Y形圈温度场的影响。结果表明:只考虑摩擦生热时,最高温度出现在Y形圈密封唇口处,考虑机械滞后生热时,最高温度出现在Y形圈根部较厚的部位,且在一定环境温度下摩擦生热对Y形圈最高温度的影响较大;相比于介质压力,活塞杆往复运动速度对Y形圈最高温度的影响更为显著,在只考虑机械滞后生热时,油液温度对Y形圈最高温度的影响较大,介质压力和往复速度对Y形圈最高温度的影响较小。 相似文献
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水介质单体液压支柱Y型密封圈的CAE优化分析 总被引:1,自引:0,他引:1
介绍了水介质单体液压支柱采用的密封元件———Y型密封圈的结构与成型;针对注射成型过程中Y型密封圈出现的主要成型缺陷———缩痕,分析了其产生的原因,提出了解决措施;运用Moldflow对Y型密封圈的注射成型过程进行CAE分析;从改进注射成型工艺参数和模具结构2个方面着手,提出3种优化方案进行CAE优化分析,并将所得之最优方案付诸于实际成型过程。依据最优方案成型的Y型密封圈其缺陷得以消除,符合水介质单体液压支柱对密封元件的要求。 相似文献
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全断面岩石隧道掘进机(TBM)刀盘滚刀布局对掘进性能有显著影响。文中针对滚刀受力与刀盘滚刀布局方法进行分析,针对刀盘径向载荷最小、刀盘倾覆力矩最小、质量分布均匀、破岩差异量最小4个优化目标进行层次分析法加权统一,建立了刀盘滚刀布局优化模型,采用具有非退化优势的免疫算法对刀盘滚刀布局进行了优化设计。以大伙房隧道的刀盘模型为工程实例,利用刀盘滚刀布局优化模型对MB264-311TBM型掘进机滚刀的优化布置进行了实践,针对米字型、螺旋线型破岩协调耦合布局及不具有耦合关系的随机型滚刀布局分别进行优化计算,优化效果显著。其中,随机型滚刀布置的优化结果明显减小了刀盘径向载荷与倾覆力矩,优化程度高达91.475%,提出基于随机型滚刀布局方式的TBM刀盘布局设计新理论。在兼顾刀盘的非性能指标约束条件下,该布局理论对于提升滚刀破岩效率、提高刀盘刀具的使用寿命具有重要的工程应用价值。 相似文献
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Clarence W.DE SILVA 《Instrumentation》2019,(4):72-84
An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t... 相似文献
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INTEGRAL EQUATION METHOD'S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES 总被引:1,自引:0,他引:1
LI Cheng ZHENG Yanping 《机械工程学报(英文版)》2008,21(6):115-118
The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value. 相似文献
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30 keV Ga+ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z2, and shows a non-monotonic relationship between contrast and Z2. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z2, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory. 相似文献
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This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an... 相似文献
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分布动态载荷识别的抗噪处理 总被引:2,自引:2,他引:0
针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性. 相似文献
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针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。 相似文献
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J. A. Williams 《Lubrication Science》1997,3(3):267-306
Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface. 相似文献
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The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar... 相似文献
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The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods.... 相似文献
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M. Stedman 《Journal of microscopy》1988,152(3):611-618
Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space. 相似文献