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为了获得大负载平行砂轮复合变幅器的设计方法,将复合变幅器简化为复合变幅杆与多阶环盘组成。利用Mindlin中厚板理论,求解了各振动环盘的位移、转角、弯矩和剪力解析表达式,并通过复合变幅杆各振动单元间的力、位移的边界条件和连续条件,以及复合变幅杆和环盘两者结构间力与位移的耦合条件,建立了复合变幅器的数学模型和频率方程。针对频率方程进行编程求解 ,设计了平行砂轮复合变幅器。通过有限元仿真分析、实物阻抗特性试验、谐振试验验证。试验结果表明:平行砂轮复合变幅器的试际谐振频率、节圆位置与理论设计的误差小于5%,验证了其理论设计方法的正确性。为研制大负载平行砂轮复合变幅器提供了一种有效的设计方法。 相似文献
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对左、右段为圆柱型、中间段为变截面杆的三段式复合扭振超声变幅杆给出了频率方程和参数计算通式据此得出中间段l2分别为指数型、类国雄型、类悬镇线型和类余弦型,而l1=l3≠0,或l1≠0;或l3≠0的各种组合复合杆的参数计算式,并算出了其参数值,给出了主要参数曲线.测试了十组典型试件的谐振频率和放大系数,实验结果与理论值基本一致,本法可组合成许多适应各种用途的扭振复合杆 相似文献
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对左、右段为圆柱型、中间段为变截面杆的三段式复合扭振超声变幅杆给出了频率方程和参数计算通式据此得出中间段l2分别为指数型、类国雄型、类悬镇线型和类余弦型,而l1=l3≠0,或l1≠0;或l3≠0的各种组合复合杆的参数计算式,并算出了其参数值,给出了主要参数曲线.测试了十组典型试件的谐振频率和放大系数,实验结果与理论值基本一致,本法可组合成许多适应各种用途的扭振复合杆 相似文献
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本文对指数型纵-扭复合振动模式的复合超声变幅杆进行了理论及实验研究,该变幅杆由均匀截面直棒及指数型截面杆组成。文中推出了变幅杆中纵向振动及扭转振动的共振频率方程,通过发迹指数型变截面棒的截面变化规律,实现了同一变幅杆中纵向振动与扭转振动的同频共振。 相似文献
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在超声振动拉丝加工过程中,为了实现线材的顺利拉拔,需要应用带有锥形孔的复合变幅杆。为此,本文基于等效四端网络与传输矩阵法,建立了带锥形孔圆锥变幅杆的传输矩阵,推导出带锥形孔圆锥过渡复合变幅杆的频率方程的一般公式。根据推导出的频率方程,应用区间搜索法和牛顿迭代法获取了准确的数值解,实现了该复合变幅杆的纵向振动。之后,应用有限元软件Ansys对设计出的复合变幅杆分别进行模态分析和动力学特性分析,获得了各段不同长度下复合变幅杆谐振频率、放大系数以及最大应力值的变化规律。最后,对制造出的复合变幅杆进行阻抗与振动性能测试,结果表明其频率准确,且振幅比较稳定。 相似文献
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以双曲正割型杆为基础的新型扭振变幅杆 总被引:2,自引:0,他引:2
推导出不存在外缘剪应力极大点的扭振超声变幅杆─-1/4波长双曲正割型杆,以此为基础组成半波长复合杆,另外1/4波长杆可以是圆柱型、指数型、类圆锥型、类悬链线型或类余弦型。对一些复合杆的谐振频率和放大系数进行了实验验证,实验结果与理论值基本一致。复合杆具有放大系数大,输人阻抗随工作频率偏移变化小,不存在外缘剪应力极大点,可输出的扭振能量大大高于同种材料的其它类型杆等一系列优点,因而对于大功率超声领域是非常有用的。 相似文献
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A simple and accurate algorithm (phase scanning method) is proposed for 3D surface contouring and dynamic response determination of a vibrating object. A sinusoidal fringe pattern is projected onto a low-frequency vibrating object by a programmable liquid crystal display projector. The fringe patterns are captured by a high-speed CCD camera with a telecentric gauging lens. Phase values are evaluated point by point using phase scanning method. From the phase values of each point on the object, the contour of the specimen at different instants of vibration can be retrieved. In this paper, a small vibrating coin is used to demonstrate the validity of the method and the experimental results are compared with test results on a stationary coin using four-step phase shifting and fast Fourier transform methods. The technique is especially useful in applications where the vibrating object has a complicated shape. 相似文献
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J. Mazumdar 《Journal of sound and vibration》1973,27(1):47-57
A method for approximate computation of the fundamental frequency of membranes of arbitrary shape vibrating harmonically is developed. The method is based upon the concept of contour lines of equal deflection on the surface of the membrane. A similar method for elastic plates has recently been developed by the author in a series of papers. As illustrations of the procedure, the method is applied to the calculation of the gravest mode of an annular, an elliptic, and a parabolic membrane. 相似文献
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The possibility of reconstructing the shape of an interference signal on the basis of the autodyne detection signal of a semiconductor laser is demonstrated in cases of harmonic and nonharmonic vibrations of the object of study. The shape of the interference signal coincides with the shape of the signal of an interference system decoupled from the radiation source. It is shown that the form of nonharmonic vibrations can be reconstructed from the values of the autodyne signal function at four varying distances from the external vibrating reflector. Numerical simulation of the procedure of reconstruction of the shape of the interference signal was performed. The main limitations of the method under consideration are discussed. 相似文献
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As a contribution to a better understanding of cavitation erosion mechanisms, a compressible inviscid finite volume flow solver with barotropic homogeneous liquid–vapor mixture cavitation model is applied to ultrasonic horn set-ups with and without stationary specimen, that exhibit attached cavitation at the horn tip. Void collapses and shock waves, which are closely related to cavitation erosion, are resolved. The computational results are compared to hydrophone, shadowgraphy and erosion test data. At the horn tip, vapor volume and topology, subharmonic oscillation frequency as well as the amplitude of propagating pressure waves are in good agreement with experimental data. For the evaluation of flow aggressiveness and the assessment of erosion sensitive wall zones, statistical analyses of wall loads and of the multiplicity of distinct collapses in wall-adjacent flow regions are applied to the horn tip and the stationary specimen. An a posteriori projection of load collectives, i.e. cumulative collapse rate vs. collapse pressure, onto a reference grid eliminates the grid dependency effectively for attached cavitation at the horn tip, whereas a significant grid dependency remains at the stationary specimen. The load collectives show an exponential decrease towards higher collapse pressures. Erosion sensitive wall zones are well predicted for both, horn tip and stationary specimen, and load profiles are in good qualitative agreement with measured topography profiles of eroded duplex stainless steel samples after long-term runs. For the considered amplitude and gap width according to ASTM G32-10 standard, the analysis of load collectives reveals that the distinctive erosive ring shape at the horn tip can be attributed to frequent breakdown and re-development of a small portion of the tip-attached cavity. This partial breakdown of the attached cavity repeats at each driving cycle and is associated with relatively moderate collapse peak pressures, whereas the stationary specimen is rather unfrequently stressed at the end of each subharmonic oscillation cycle by the violent collapse of the complete cavity. 相似文献
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Mixing time measurements have been carried out in a cylindrical reactor irradiated with an ultrasonic horn fitted with different size tips. Liquid phase bulk velocities induced by the vibrating horn surface have been estimated from the mixing time measurements. A relationship has been established between the mean horn surface velocities (frequency x amplitude) and the mean velocities estimated from the mixing time measurements. A correlation has been developed for the prediction of the mixing time using a method similar to that used for liquid jet mixing. This could be the first step in defining the overall flow field, the information about which can then be used to get realistic numerical solutions of the Rayleigh-Plesset equation for a travelling cavity to understand the cavity dynamics in the various parts of the ultrasonic horn reactor. 相似文献
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To address difficulties in treating large volumes of liquid metal with ultrasound, a fundamental study of acoustic cavitation in liquid aluminium, expressed in an experimentally validated numerical model, is presented in this paper. To improve the understanding of the cavitation process, a non-linear acoustic model is validated against reference water pressure measurements from acoustic waves produced by an immersed horn. A high-order method is used to discretize the wave equation in both space and time. These discretized equations are coupled to the Rayleigh-Plesset equation using two different time scales to couple the bubble and flow scales, resulting in a stable, fast, and reasonably accurate method for the prediction of acoustic pressures in cavitating liquids. This method is then applied to the context of treatment of liquid aluminium, where it predicts that the most intense cavitation activity is localised below the vibrating horn and estimates the acoustic decay below the sonotrode with reasonable qualitative agreement with experimental data. 相似文献
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In this paper, new explicit and exact travelling wave solutions for a compound KdV-Burgers equation are obtained by using the hyperbola function method and the Wu elimination method, which include new solitary wave solutions and periodic solutions. Particularly important cases of the equation, such as the compound KdV, mKdV-Burgers and mKdV equations can be solved by this method. The method can also solve other nonlinear partial differential equations. 相似文献
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Hong Zhao 《Czechoslovak Journal of Physics》2006,56(8):799-805
In this paper, new explicit and exact solutions for a compound KdV-Burgers equation are obtained using the hyperbolic function
method and the Wu elimination method, which include new solitary wave solutions and periodic solutions. Particularly important
cases of the equation, such as the compound KdV, mKdV-Burgers and mKdV equations can be solved by this method. The method
can also be applied to solve other nonlinear partial differential equation and equations. 相似文献