Papers by Keyword: Natural Frequency

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Authors: De Chen Zhang, Chao Wen Dong, Ming Yang, Yan Ping Sun
Abstract: The vibration of the fifth frame mill of 1450 Cold Tandem Rolling Mill in the rolling process was studied using finite element software ANSYS. The dynamic analysis of one-piece frame and two-piece frame on the fifth frame mill were carried on. The natural frequency and mode of vibration were calculated. Through analyzing, we obtained that two-piece frame performed better.
Authors: Ming Yang, Zhi Chun Yang
Abstract: To penetrate into the study of POGO vibration, by taking the LRC equivalent circuit analyzing method, based on two boundary conditions in document [, taking the flow pulse drive into consideration, this paper proposes four boundary conditions specific to the propelling flow system in liquid rockets, and at the same time, complements the mathematic model. Further, by way of network function, under the liquid system flow parameter, this paper infers transfer function expressions, and makes the accurate solution of the natural frequency under every boundary condition. At last, from the statistic point of view, by the method of correlation coefficient, this paper studies the influence that the flow parameter may have on the system natural frequency, and set the major influential liquid flow parameter to the system natural frequency of liquid propelling flow system in liquid rockets.
Authors: Jun Zhang, Yi Min Song, Jin You Xu
Abstract: A discrete lumped-parameter model for a general planetary gear set is proposed, which models the continuous flexible ring gear as discrete rigid ring gear segments connected with each other through virtual springs. The ring-planet mesh is analyzed to derive equations of motion of ring segments and planet. By assembling equations of motion of each individual component, the governing equations of planetary gear system are obtained. The solution for eigenvalue problem yields to natural frequencies and corresponding vibration modes. The simulations of example system reveal that the ring gear flexibility decreases system lower natural frequencies and the vibration modes can be classified into rotational, translational, planet and ring modes.
Authors: Sam Young Noh, Eun Mi Sin
Abstract: The purpose of the study is the development of a tool for the prediction of the structural damage by means of the numerical damage simulation in the design stage. For the evaluation of the structural integrity in the numerical damage analysis, a global damage indicator was defined based on the modal parameters obtained from the tangential equation of motion: a set of natural frequencies and mode shapes. As they are given in a set, it may be difficult to treat them as a damage indicator. In this study a new damage indicator based on the natural frequencies was defined using the contribution factors of the mode shapes under consideration of the external modal energy. A numerical example of a frame structure showed the efficiency of the damage indicator defined in the study.
Authors: Guo Qing Zhou, Ji Wang, Song Xiang
Abstract: The novelty of this paper is the use of a meshless local collocation method based on the multiquadric radial basis functions for free vibration analysis of functionally graded plates. This method approximates the governing equations based on first-order shear deformation theory using the nodes in the support domain of any data center. The natural frequencies computed by the present method are in good agreement with the element-free solutions of Zhao et al.
Authors: Daniel Turcanu, Iulian Nicola, Tudor Prisecaru, Cristian Predoi
Abstract: The paper presents the summary of the finding solution process for the vibrations attenuation of a ground moving system designed for a terrestrial / aerial drone. A spring was calculated, a damping system was designed and natural frequency simulated. Comparison was made between the natural frequencies obtained for both situations: the ground moving system equipped with the damper and without the damper.Key words: natural frequency, modal analysis, 3D printing, dumper.
Authors: Jia Lian Shi, Xu Yang, Da Dong Ma
Abstract: The model of eccentric shaft of caster vibration device is built by finite element software ANSYS, and bearings are regarded as rigid constraints and elastic constraints.Firstly, regarding the bearings as rigid constraints, the nodes on the parts of eccentric shaft, which match with bearing,are exerted full constraints. Secondly, regarding bearings as elastic constraints, spring, which is built by elastic element combination 14, are used to replace the bearings. In addition, the full constraints are exerted on the one side of spring,and axial constraint are exerted on the other side. Afterwards make the modal analysis of eccentric shaft.Solve and extract the first six natural frequency and modal shape.Watch and analyse the breaking formal of eccentric shaft as it is in different mode. The basis are settled for instantaneous and harmonic analysis.
Authors: Guo Jian Huang, Cheng Zhong He, Xin Hua Wang
Abstract: Old giant cranes in corrosive environment are in serious hidden danger of structural instability and failure, the modal analysis is an important part of dynamics analysis in the Crane Safety Evaluation to guarantee the safety of cranes. A Modal Analysis of a 28-year old 100t giant shipbuilding tower crane was done using ANSYS. Comparing with the vibration frequencies and modal shapes, Modal analysis shows that the Natural Frequency of the crane reduces from 1.0024Hz to 1.0003Hz, beside all the Modal vibration frequencies (first 10 Order) of the crane are lower than the designed value, means the strength of the tower crane has decreased; the Modal Vibration Frequencies (first 10 Order) of the tower crane are between 1 Hz and 2 Hz. The Mmodal analysis provided theoretical basis for safe use, design and transformation of this crane.
Authors: M. Khoshbayani Arani, N. Rasekh Saleh, M. Nikkhah Bahrami
Abstract: Analytical solutions for vibration analysis of the rods with variable cross section are in general complex and in many cases impossible. On the other hand, approximate methods such as the weighted residual, Rayleigh-Ritz and finite difference methods also have their own shortcomings such as a limited number of natural frequencies and accuracy. Using the wave propagation method, the structure is partitioned into several continuous segments with constant cross-section, for which there exists an exact analytical solution. Waves in positive and negative directions at the entrance of each segment are obtained in terms of waves at the initial segment. Then, by satisfying the boundary conditions, the characteristic equation is obtained and all natural frequencies are calculated. By adding waves in positive and negative directions at each point, the shape modes are obtained. To verify this modified method, the frequencies and mode shapes of a rod with polynomial cross section, which has an exact analytical solution, are compared and have proven to be of highly accuracy. Therefore, this method can also be used to calculate the natural frequencies and its mode shapes of the rods with variable cross section for which no analytical solution is available.
Authors: Peng Xu, Yu Tao Men, Bao Shan Xu, Qiang Yang, Jun Lu, Chun Qiu Zhang
Abstract: The mechanical environment has an important influence on biological behavior of the human musculoskeletal system. Either in vivo or in vitro culture, the growth and development of the musculoskeletal tissue depend on the mechanical environment. Now we propose a new loading device which uses a voice coil motor as driving force to further optimize tissue engineering bioreactor. It can not only provide tissue engineering in vitro culture with different sizes and frequency of loading environments within the physiological range, but also detect the mechanical properties of the culture in building process. This device, which uses the voice coil motor as driving force and closed-loop encoder to control displacement, has the characteristics of low power loss, high acceleration and smooth loading, and can achieve a high-precision loading process with different ranges such as from high-speed to low-speed. The device can facilitate the load research in build process of the engineered musculoskeletal system.
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