共查询到20条相似文献,搜索用时 31 毫秒
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Khodabakhsh Saeedi Alfin Leo Rama B. Bhat Ion Stiharu 《Journal of Mechanical Science and Technology》2012,26(5):1439-1448
The free vibration of a circular plate with multiple perforations is analyzed by using the Rayleigh-Ritz method. Admissible functions are assumed to be separable functions of radial and tangential coordinates. Trigonometric functions are assumed in the circumferential direction. The radial shape functions are the boundary characteristic orthogonal polynomials generated following the Gram-Schmidt recurrence scheme. The assumed functions are used to estimate the kinetic and the potential energies of the plate depending on the number and the position of the perforations. The eigenvalues, representing the dimensionless natural frequencies, are compared with the results obtained using Bessel functions, where the exact solution is available. Moreover, the eigenvectors, which are the unknown coefficients of the Rayleigh-Ritz method, are used to present the mode shapes of the plate. To validate the analytical results of the plates with multiple perforations, experimental investigations are also performed. Two unique case studies that are not addressed in the existing literature are considered. The results of the Rayleigh-Ritz method are found to be in good agreement with those from the experiments. Although the method presented can be employed in the vibration analysis of plates with different boundary conditions and shapes of the perforations, circular perforations that are free on the edges are studied in this paper. The results are presented in terms of dimensionless frequencies and mode shapes. 相似文献
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D. G. Milovzorov V. Kh. Yasoveev 《Optoelectronics, Instrumentation and Data Processing》2017,53(4):388-394
Issues of designing fluxgate magnetic gradiometers are considered. The areas of application of fluxgate magnetic gradiometers are determined. The structure and layout of a two-component fluxgate magnetic gradiometer are presented. It is assumed that the fluxgates are strictly coaxial in the gradiometer body. Elements of the classical approach to the mathematical modeling of the spatial arrangement of solids are considered. The bases of the gradiometer body and their transformations during spatial displacement of the gradiometer are given. The problems of mathematical modeling of gradiometers are formulated, basic mathematical models of a two-component fluxgate gradiometer are developed, and the mathematical models are analyzed. A computer experiment was performed. Difference signals from the gradiometer fluxgates for the vertical and horizontal position of the gradiometer body are shown graphically as functions of the magnitude and direction of the geomagnetic field strength vector. 相似文献
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应用于油气钻采的磨料水射流喷嘴优化设计与试验研究 总被引:1,自引:0,他引:1
为了优化总长度和出口直径被限制的喷嘴的内部结构,进行喷嘴内外流场数值模拟、喷嘴流量系数测试以及喷嘴对砂岩冲蚀深度的试验。对试验结果进行分析表明,各喷嘴射流轴心线上的速度在喷嘴的内部达到最大后开始减小;数值模拟结果和流量系数测试结果相吻合,即喷嘴外部射流速度最大的喷嘴流量系数也最大,该喷嘴的工作性能最好;在设计试验的喷嘴范围内,进口收缩角为30°,出口圆柱段长度为11mm的喷嘴性能最好,其对砂岩的冲蚀深度高出其他喷嘴的200mm~300mm。 相似文献
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N. P. Aleshin V. V. Murashov A. G. Evgenov M. V. Grigoriev N. A. Shchipakov S. A. Vasilenko I. S. Krasnov 《Russian Journal of Nondestructive Testing》2016,52(1):38-43
Flaws in metal parts that are typical for the selective laser melting technique are considered. The flaws are divided into four groups by the degree of their danger. The quantitative and qualitative indices of the flaws are given and the causes of their formation are described. 相似文献
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针对两类常见的制造加工约束即对称性和重复性下的连续体拓扑优化问题,提出了将敏度值在每轮优化前的修正方法,该方法简单且易于编程实现,实现了对称性或重复性约束条件下连续体拓扑优化设计,通过数值算例对不同制造加工约束下的拓扑结果进行了分析对比,结果表明,研究方法具有可行性和有效性。 相似文献
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Yu. I. Sazonov 《Russian Journal of Nondestructive Testing》2006,42(12):823-836
Features of electron-beam welding (EBW), various types of flaws arising in welded joints during EBW, and the factors causing these flaws’ appearance are considered. The effects of beam focusing and the thickness of the welded metals on the shape of a seam are demonstrated. EBW flaws are classified. The difficulties associated with obtaining informative parameters during EBW are analyzed. Radiation and acoustic methods for engineering diagnostics of EBW are considered. New approaches to the construction of systems for diagnostics of EBW are proposed. Experimental results are presented. 相似文献
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呼守信 《机电产品开发与创新》2011,24(6):135-137
介绍了履带式采掘设备变频调速装置的主回路和控制回路,通过对控制系统的分析和现场试验,设置了适合采掘设备工况的变频器参数,针对变频器的矢量控制,确定了矢量控制下的电机参数,并分析了变频器运行中常见的故障,给出了故障原因和采取的策略. 相似文献
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用D ynaform软件对不锈钢盖成形过程进行了模拟,通过模拟,使拉深工艺与模具结构更合理,减少了试模、修模的次数,防止了缺陷,降低了生产成本。模拟结果与拉深产品相吻合,产品质量良好,满足了生产要求。 相似文献
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网络化的离心压缩机组振动在线监测及故障诊断系统的研究 总被引:1,自引:0,他引:1
提出了一种网络化的大机组振动在线监测和故障诊断系统。论述了系统网络化的意义和重要性。介绍了系统各部分的组成和功能。 相似文献
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V. A. Baranov U. Ewert H. M. Kröning V. V. Brazovsky E. S. Uchaikina V. K. Kuleshov 《Russian Journal of Nondestructive Testing》2011,47(10):696-700
Methods of nonlinear backprojection that are suitable for the solution of problems in tomography with small number of views
are considered. Their comparison with the classical back-projection methods is performed. Examples of reconstructions are
given; the fields in which back-projection methods are successfully applied are enumerated. 相似文献
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M. Yu. Kataev A. V. Lavygina I. A. Khodashinskii D. A. Epshtein 《Optoelectronics, Instrumentation and Data Processing》2010,46(2):134-141
Algorithms of constructing a fuzzy approximator of atmospheric temperature fields are considered. The consequent parameters
of the fuzzy rule approximator are determined using the leastsquares method, and the antecedent parameters are determined
by the genetic algorithm. Results of a numerical experiment are presented. Optimal approximator parameters are given. 相似文献
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基于活动标架法的二自由度机器人操作性能分析 总被引:1,自引:0,他引:1
用活动标架法研究了二自由度机器人机构的运动学 ,得出了机器人机构的一些不变量 ,并根据它们定义了机器人的平移体积、旋转体积、可操作性指标和灵活度 ,用这些指标评价机器人的操作性能。并由此得出了机器人产生奇异的条件 ,研究了工作空间曲面和奇异曲面的几何性质 ,计算了它们的法曲率和高斯曲率 相似文献
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开敞式混流泵内流的数值模拟与出水机构选择 总被引:3,自引:0,他引:3
为了给新型开敞式混流泵的设计积累经验并为特殊出水流道结构设计提供方法,对具有不同出水机构的开敞式混流泵进行数值模拟,分析从小流量到最大流量下的内部流动和水力性能,提出适应特殊液压动力需求的开敞式出水机构方案。给出内部流动数值模拟和性能预测的方法,通过外特性预测结果与模型试验数据的比较,验证数值计算的可靠性。在模型分析基础上,针对轴向有导叶、轴向无导叶和径向无导叶等不同的开敞式出水结构形式,进行整机内部流动分析和外特性预测,对不同结果进行比较分析,给出不同出水机构对于特定结构和动力需求的适应性。 相似文献
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V. L. Krupenin 《Journal of Machinery Manufacture and Reliability》2013,42(4):269-275
Examples of the appearance of vibrational motion modes, which lead to excess noise and premature wear of machine parts and mechanisms are presented. Models of mechanical filters of various types are considered, and the problems of the nonlinear and linear filtration of wave-vibrational processes are discussed. The models of the vibration-conducting media, involving the nonlinear vibrational guides of a complex structure, are presented. The analytical studies of the problems associated with the passage of periodically strongly nonlinear (vibroimpact) processes through the multidimensional machine designs, which are modeled by means of discrete 2D mechanical systems with regular structures, or multidimensional mechanical filters for low frequencies, are performed. The physical sense of the derived solutions is obtained, the computational formulas are derived, and the main dynamic effects are discussed. The notion of filter metrics is introduced. 相似文献