2013 ◽  
Vol 690-693 ◽  
pp. 3023-3026
Author(s):  
Jun Zhang ◽  
Chun Ren Tang ◽  
Hong Mei Tang ◽  
Xian Hua Li ◽  
Meng Meng Niu ◽  
...  

It is significant to study the dynamic characteristics of the mechanical system. In order to prevent accidents such as resonance and self-excited shock, modal analysis of the mechanical systems should be analyzed. The mode shape of gears was analyzed to improving the design security. The sleeve, the planet gears and the internal gear of the motor were simulated. All order natural frequency, the mode shape of the motor was obtained. Research shows that motor running is smooth when the frequency is less than 4230Hz.


2020 ◽  
Vol 896 ◽  
pp. 75-82
Author(s):  
Leonard Marius Ciurezu-Gherghe ◽  
Gabriel Cătălin Marinescu ◽  
Andra Raluca Constantin ◽  
Nicolae Dumitru

This paper addresses to a dynamic modal analysis of a crank-type mechanism. The proposed mechanism will have all the components considered as deformable bodies. Thus, the proposed research consists on two methods, namely an analytical and a numerical one. The analytical method allows to identify the static and dynamic components of the matrices that from the equation of motion based on the Kane formalism and the finite element modeling. The numerical method is based on the virtual prototyping of the whole assembly with the ADAMS software. In this case, for the deformable bodies analysis, will be used the method of superposition which have on its base the modal analysis and the RR Craig and MCC Bampton procedure.


Vibration ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 853-864
Author(s):  
Allan de Barros ◽  
Ahmed Galai ◽  
Amir Ebrahimi ◽  
Babette Schwarz

The vibration on the stator core of hydrogenerators caused by electromagnetic forces is an important factor affecting the reliability and long-lasting operation of a machine. For a suitable addressment of the problem, it is necessary to accurately predict the eigenmodes and eigenfrequencies of the mechanical system. However, different results for the eigenfrequencies can be achieved depending on the applied model and material parameters. This work contributes to solving this issue by investigating the impact of different input parameters on the eigenmodes and eigenfrequencies calculated by analytical and numerical models. The results are discussed and compared to measurements performed on a prototyped 732 kVA hydrogenerator.


2021 ◽  
Vol 147 (3) ◽  
pp. 04020100
Author(s):  
Nasser Heydari ◽  
Panayiotis Diplas ◽  
J. Nathan Kutz ◽  
Soheil Sadeghi Eshkevari

Author(s):  
S. R. Rakhmanov ◽  
V. V. Povorotnii

To form a necessary geometry of a hollow billet to be rolled at a pipe rolling line, stable dynamics of the base equipment of the automatic mill working stand has a practical meaning. Among the forces, acting on its parts and elements, significant by value short-time dynamic loads are the least studied phenomena. These dynamic loads arise during transient interaction of the hollow billet, rollers, mandrel and other mill parts at the forced grip of the hollow billet. Basing of the calculation scheme and dynamic model of the mechanical system of the ТПА 350 automatic mill working stand was accomplished. A mathematical model of dynamics of the system “hollow billet (pipe) – working stand” within accepted calculation scheme and dynamic model of the mechanical system elaborated. Influence of technological load of the rolled hollow billet variation in time was accounted, as well as variation of the mechanical system mass, and rigidity of the ТПА 350 automatic mill working stand. Differential equations of oscillation movement for four-mass model of forked sub-systems of the automatic mill working stand were made up, results of their digital calculation quoted. Dynamic displacement of the stand elements in the inter-roller gap obtained, which enabled to estimate the results of amplitude and frequency characteristics of the branches of the mill rollers setting. It was defined by calculation, that the maximum amplitude of the forced oscillations of elements of the ТПА 350 automatic mill working stand within the inter-roller gap does not exceed 2 mm. It is much higher than the accepted value of adjusting parameters of the deformation center of the ТПА 350 automatic mill. A scheme of comprehensive modernization of the rollers setting in the ТПА 350 automatic mill working stand was proposed. It was shown, that increase of rigidity of rollers setting in the ТПА 350 automatic mill working stand enables to stabilize the amplitude of forced oscillations of the working stand elements within the inter-rollers gap and considerably decrease the induced nonuniform hollow billet wall thickness and increase quality of the rolled pipes at ТПА 350.


2015 ◽  
Vol 39 (1) ◽  
pp. 145-149 ◽  
Author(s):  
Ewa B. Skrodzka ◽  
Bogumił B.J. Linde ◽  
Antoni Krupa

Abstract Experimental modal analysis of a violin with three different tensions of a bass bar has been performed. The bass bar tension is the only intentionally introduced modification of the instrument. The aim of the study was to find differences and similarities between top plate modal parameters determined by a bass bar perfectly fitting the shape of the top plate, the bass bar with a tension usually applied by luthiers (normal), and the tension higher than the normal value. In the modal analysis four signature modes are taken into account. Bass bar tension does not change the sequence of mode shapes. Changes in modal damping are insignificant. An increase in bass bar tension causes an increase in modal frequencies A0 and B(1+) and does not change the frequencies of modes CBR and B(1-).


Author(s):  
Jianhua Huang ◽  
Shuyun Jiang ◽  
Zerong Guo ◽  
Yonghe Jiao
Keyword(s):  

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