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为了使纵弯谐振变幅器的输出振幅满足齿轮超声加工的要求,设计了一个带有级联变幅杆的变幅器.利用Mindlin中厚板理论,根据变幅杆各段的力和位移耦合条件、变幅杆与齿轮的力和位移耦合条件、边界条件,推导出变幅器的频率方程和位移方程,实现了变幅器的设计,并求得变幅器的振幅分布曲线.通过理论求解、有限元软件ANSYS进行模态分析和谐响应分析、变幅器谐振特性试验分析变幅器的动力学特性,得出三者的结果一致,齿轮分度圆处的振幅为12μm,较常用的变幅器有了较大的提高,满足了齿轮超声加工的需求. 相似文献
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多种材料的阶梯环盘负载与变幅杆共同组成了功率超声纵弯谐振变幅器,在超声加工、超声处理等领域有着广泛应用。为了快速准确地对纵弯谐振变幅器进行设计,提出了一种基于Mindlin理论的变幅器设计方法。基于Mindlin理论求出了中厚环盘单元的位移、转角、弯矩和剪力的解析表达式。通过振动单元间的连续条件和边界条件,建立了纵弯谐振变幅器的振动模型与频率方程。基于该振动模型,利用MATLAB/GUI开发了纵弯谐振变幅器尺寸设计软件。通过理论计算设计了纵弯谐振变幅器,并进行了有限元模态分析、阻抗分析试验和超声谐振试验。仿真与试验的结果证明,基于Mindlin理论的纵弯谐振变幅器设计方法所设计的纵弯谐振变幅器的谐振频率与设计频率相符合,具有较好的设计精度,可为变幅器设计提供参考。 相似文献
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为了解决齿轮超声加工纵向振动系统设计问题,基于纵向振动动力学方程,利用结合面的力、位移振动耦合与边界条件,提出纵向振动变幅器的非谐振设计方法,推导了频率方程;应用Matlab2011Ra对变幅器未知尺寸、振型分布进行理论数值求解,并利用ANSYS12.0对所设计变幅器进行模态分析与谐响应分析.设计加工了不同模数齿轮的纵向振动变幅器,基于C6140车床搭建了齿轮超声加工纵向振动系统的激光测振仪测试系统,进行谐振实验.变幅器的谐振频率和振幅经理论求解、有限元分析、实验测试对比,各自的最大求解偏差都小于5%,可以满足工程应用需要.研究表明:可应用力、位移耦合非谐振设计方法,完成中小模数齿轮变幅器的纵向振动系统设计,对齿轮超声振动系统设计具有理论指导和工程应用价值. 相似文献
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砂轮变幅器是旋转超声内圆磨削谐振系统的关键部件,其设计质量直接影响超声磨削的工艺效果。但目前内圆磨削砂轮变幅器缺乏较为完善的理论分析模型。为提高砂轮变幅器理论分析模型的通用性,基于非谐振设计理论建立了纵向谐振砂轮变幅器的理论分析模型,并利用砂轮变幅器各振动单元间的力、位移连续条件与边界条件推导了其频率方程。然后,针对频率方程进行编程求解,并通过ANSYS有限元仿真分析进行验证。最后,加工制作了纵向谐振砂轮变幅器,并开展阻抗特性分析试验、超声谐振试验和振动位移测量试验,分析了其谐振特性。试验结果表明,所研制的砂轮变幅器的谐振试验频率与理论设计频率一致,其输出端振动位移的试验值与仿真值的相对误差为7.83%,符合旋转超声内圆磨削的要求,验证了理论分析模型求解的正确性。研究结果为旋转超声内圆磨削砂轮变幅器的设计提供了便捷且有效的方法。 相似文献
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《振动工程学报》2016,(2)
基于细长杆纵振理论和薄圆盘振动理论,针对超声变幅杆与杯型工具开展一体化设计研究。通过分析各段的振动模态,将超声变幅杆和杯型工具的振动分为"纵-弯-纵"三个部分,分别建立三段位移和应力函数及边界条件,推导得出超声变幅杆和杯型工具的总体频率方程。根据得到的总体频率方程,设计出典型的超声变幅杆和杯型工具。对所设计的超声变幅杆和杯型工具的振动性能进行有限元分析和试验测试,分析和试验结果表明,超声变幅杆和杯型工具谐振频率的设计结果和有限元分析及测试结果的误差均在10%以内,验证了所建立的超声变幅杆和杯型工具的频率方程的正确性,并分析了各段长度和半径对超声变幅杆和杯型工具谐振频率的影响规律,为其谐振频率的修正提供了依据。 相似文献
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计算了圆柱截面阶梯形变幅杆的一阶到六阶纵振动模式的谐振频率,较系统地分析研究了带与不带过渡段的阶梯杆之谐振频率随其粗细段长度比和直径比的变化规律,得到了一些新结果。用两种方法计算谐振频率:一种是求解一维近似解析频率方程,计算程序用MATLAB编制。另一种是用有限元仿真数值计算,利用ANSYS软件,且适合对于任意材料和几何参数的圆截面阶梯杆的任意阶谐振频率的计算。有限元计算与一维近似理论计算得到的频率的变化趋势基本一致。所给频率变化趋势对于变幅杆的设计和加工都能提供参考。在相当大的阶梯杆几何参数空间内,一阶谐振频率随变幅杆粗段与过渡段长度而相应减小。对于实测频率比所期望值高的变幅杆进行频率调整时可以利用上述性质。 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