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为实现对微量摩阻天平/MEMS摩阻传感器进行静态校准研究,并且需要能够模拟高超声速风洞试验环境压力,建立微量摩阻天平旋转加载校准装置,对该校准装置的总体方案、旋转加载台体系统、真空系统和测控系统等进行研究。首先,提出基于离心力等效原理和真空箱体内单轴旋转加载方法的校准装置研制方案,开展旋转加载校准原理和校准装置总体方案研究。然后,分别对单轴旋转加载台体系统、模拟不同风洞试验环境压力的真空系统、旋转加载台体和真空箱体的磁流体动态密封以及专用的测控系统等方案进行详细设计。最后,完成校准装置研制,对该校准装置进行技术指标检测,并对研制的MEMS摩阻传感器样机开展校准应用。结果表明:微量摩阻旋转加载校准装置的速率范围在0.01~3 600°/s连续可调,速率精度优于0.01°/s,真空度20~5 000 Pa精密可测可控;静校的MEMS摩阻传感器样机输出稳定、回零好,测量范围均为0~100 Pa,分辨率为0.1 Pa,重复性精度和线性度优于1%。该校准装置速率精度高、稳定性好,校准过程中真空箱体的真空度可在30 min内达到20 Pa并得到很好保持,满足微量摩阻天平/MEMS摩阻传感器静态校准需求。 相似文献
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《中国测试》2020,(8)
为研究尾部支撑风洞天平的静态校准公式能否直接用于该天平实际使用中的腹部支撑风洞试验,该文从具体案例出发,利用ANSYS软件模拟天平在校准和实际使用状态下的虚拟加载过程。通过计算获得天平的法向力、俯仰力矩分量的主项系数以及俯仰力矩对法向力的干扰系数。对天平进行两种状态下的加载校准以获得实测的主项系数以及干扰系数。比较两种方法获得的各项系数,结果显示:虚拟加载获得的各项系数与实测结果一致。该研究表明:天平与支撑的连接刚度对天平静态校准公式的使用存在一定影响,若天平同腹部支撑的连接刚度与天平同尾部支撑的连接刚度差异较小,即静态校准与使用状态一致,则试验时可直接采用天平与尾部支撑组合状态下的天平静态校准状态公式;若两者存在较大差异,需对采用尾部支撑进行静态校准获得的天平公式中的部分系数进行修正。 相似文献
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研究了直升机旋翼气动试验测力天平原位校准技术。针对安装于直升机全尺寸旋翼试验塔顶部的机械式多分量气动力测量天平的测量原理和结构特点,确定了基于力叠加原理的组合加载原位校准方法。依其原理研制了原位校准装置,介绍了装置的关键机械结构设计,及基于自适应协同算法的控制系统;研制了高精度微小形变测量系统并评估校准误差;通过旋翼试验塔现场的原位校准试验对校准装置性能进行了验证。结果表明:各力素的原位相对校准不确定度均优于0.1%(k=2),被校系统各分力的相对线性度均优于1%。通过原位校准可获得新的天平工作公式。 相似文献
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主要介绍了可实现六个分量力和力矩独立或组合加载的校准装置主机结构的设计思路和具体组成。针对该装置量程宽、空间大、准确度高等特点,文章分析了装置研制过程中涉及的技术难点;围绕多分量力组合加载的实现问题,说明了多分量力组合加载的方法原理设计及加载装置主机的机械结构设计等技术问题;最后说明了校准装置实现的技术性能和试验验证情况。 相似文献
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通过设计一种智能压力校准装置,利用计算机通过软件对装置进行控制,实现对压力仪表的自动校准。经过反复试验,该装置运行稳定可靠。经评定,该装置的不确定度为0.02%,可开展0.1%精度压力仪表的计量校准工作。 相似文献
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《International journal for numerical methods in engineering》2018,113(9):1488-1506
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method. 相似文献
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Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.…… 相似文献
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A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa. 相似文献
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On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.…… 相似文献
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Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß. 相似文献
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C. Qihong W. Zhan‐Wen J. Yi J. Yehua L. Fei F. Hanguang 《Materialwissenschaft und Werkstofftechnik》2014,45(7):582-590
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill. 相似文献
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Dimiter Hadjistamov 《材料科学与工程:中英文B版...》2019,(2):56-65
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ... 相似文献
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《中国标准化(英文版)》2014,(4)
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from 相似文献
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《中国标准化(英文版)》2014,(5)
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively. 相似文献