Effect of Centrifugal Force on Frequency Characteristic of Rotating Hollow Cylinders Using a Newly Designed Cylindrical Super Element

2006 ◽  
Author(s):  
M. Bonakdar ◽  
M. T. Ahmadian
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Free Vibration ◽  
Centrifugal Force ◽  
Natural Frequencies ◽  
Rotating Cylinder ◽  
Finite Cylinder ◽  
Vibration Frequencies ◽  
Hollow Cylinders ◽  
Special Case

A sixteen node cylindrical super element is presented for evaluating the free vibration characteristics of a rotating laminated cylinder with conventional boundary conditions. It is shown that the natural frequencies are affected considerably when the centrifugal force is also taken into account. The vibration frequencies of rotating finite cylinder, obtained by conventional finite element are used to evaluate the accuracy of this approach. The special case of a stationary cylinder with zero spinning velocity is also considered as a check on this method. Results indicate only few number of cylindrical super elements are capable of predicting the natural frequency of the rotating cylinder within the same limit as many elements used in the conventional finite element method.

Free Vibration Analysis of Circular FGM Plate Having Variable Thickness Under Axisymmetric Condition by Finite Element Method

2005 ◽  
Author(s):  
M. Nikkhah-Bahrami ◽  
Abazar Shamekhi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Free Vibration ◽  
Variable Thickness ◽  
Vibration Analysis ◽  
Natural Frequencies ◽  
Free Vibration Analysis ◽  
Thickness Variation ◽  
Simply Supported ◽  
Element Method

This study presents the free vibration analysis of circular plate having variable thickness made of functionally-graded material. The boundary conditions of the plate is either simply supported or clamped. Dynamic equations were obtained using energy method based on Love-Kichhoff hypothesis and Sander’s non-linear strain-displacement relation for thin plates. The finite element method is used to determine the natural frequencies. The results obtained show good agreement with known analytical data. The effects of thickness variation and Poisson’s ratio are investigated by calculating the natural frequencies. These effects are found not to be the same for simply supported and clamped plates.

Free vibration analysis of the hard-coating splitter blisk using the energy-based finite element method

2019 ◽  
Vol 233 (13) ◽  
pp. 4577-4589 ◽  
Author(s):  
Feng Gao ◽  
Wei Sun
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Free Vibration ◽  
Vibration Analysis ◽  
Natural Frequencies ◽  
Complex Modulus ◽  
Free Vibration Analysis ◽  
Hard Coating ◽  
Mindlin Plate ◽  
Element Method

This paper presents the free vibration analysis of the hard-coating splitter blisk (known as the splitter blisk deposited hard coating) and the damping-improved performance of the hard coating for vibration suppression of the splitter blisk. Based on the proposed energy-based finite element method by the energy considerations, complex modulus theory and composite Mindlin plate theory, the equations of motion of hard-coating splitter blisk are formulated. And, the complex solutions for free vibration problem are then solved, whose real and imaginary parts are closely related to natural frequencies and loss factors. Considering the academic splitter blisk deposited NiCoCrAlY+YSZ hard coating as the benchmark, the comparisons for vibration characteristics of hard-coating splitter blisk originating from different sources are performed for model validation, and the influence of hard coating on the dynamics of splitter blisk are also investigated. The numerical results reveal that the vibration amplitudes of splitter blisk are suppressed remarkably by the hard coating without altering natural frequencies significantly.

scholarly journals Structural static and modal frequency simulations in a coffee harvester’s chassis

2018 ◽  
Vol 22 (7) ◽  
pp. 511-515 ◽  
Author(s):  
Evandro P. da Silva ◽  
Fábio M. da Silva ◽  
Ednilton T. de Andrade ◽  
Ricardo R. Magalhães
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Load Distribution ◽  
Natural Vibration ◽  
Natural Frequencies ◽  
Rear Wheel ◽  
Vibration Frequencies ◽  
The Finite Element Method ◽  
Uniform Load ◽  
Modal Frequency

ABSTRACT Coffee harvesters are subject to stresses and vibrations in their structure, originating from engines and harvesting system. These structures must be designed to avoid rupturing of the components due to fragility of the materials, inadequate geometries, or the phenomenon of resonance, which increases the displacements/deformations of the components. In this scenario, the main objective of this study is to analyse the results of stresses and displacements from two static simulations and to present results of natural vibration frequencies from two modal simulations in a self-propelled coffee harvester. For this purpose, 20 modal shapes were generated, considering coffee harvester reservoir as empty and full. The simulations were carried out using the finite element method in which actual boundary conditions were applied to the motor chassis of the harvester. As results, stresses above the material’s yield strength were observed in some regions of the components. Greater displacements were observed at the rear of the chassis, suggesting a new positioning of the rear wheel to obtain a uniform load distribution. Some natural frequencies, which presented greater displacements/deformations, can be affected by the operation of the main motor, also associated with the vibrating system in the coffee harvest, which may cause rupture of components.

scholarly journals Out-of-Plane Vibration of Curved Uniform and Tapered Beams with Additional Mass

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Hamdi Alper Özyiğit ◽  
Mehmet Yetmez ◽  
Utku Uzun
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Natural Frequencies ◽  
Variable Cross ◽  
Additional Mass ◽  
Inertia Effects ◽  
Tapered Beam ◽  
Out Of Plane ◽  
Good Agreement

As there is a gap in literature about out-of-plane vibrations of curved and variable cross-sectioned beams, the aim of this study is to analyze the free out-of-plane vibrations of curved beams which are symmetrically and nonsymmetrically tapered. Out-of-plane free vibration of curved uniform and tapered beams with additional mass is also investigated. Finite element method is used for all analyses. Curvature type is assumed to be circular. For the different boundary conditions, natural frequencies of both symmetrical and unsymmetrical tapered beams are given together with that of uniform tapered beam. Bending, torsional, and rotary inertia effects are considered with respect to no-shear effect. Variations of natural frequencies with additional mass and the mass location are examined. Results are given in tabular form. It is concluded that (i) for the uniform tapered beam there is a good agreement between the results of this study and that of literature and (ii) for the symmetrical curved tapered beam there is also a good agreement between the results of this study and that of a finite element model by using MSC.Marc. Results of out-of-plane free vibration of symmetrically tapered beams for specified boundary conditions are addressed.

scholarly journals Modeling and Eigenfrequency Analysis of Sound-Structure Interaction in a Rectangular Enclosure with Finite Element Method

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Samira Mohamady ◽  
Raja Kamil Raja Ahmad ◽  
Allahyar Montazeri ◽  
Rizal Zahari ◽  
Nawal Aswan Abdul Jalil
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequencies ◽  
Active Noise Control ◽  
Interior Noise ◽  
Rectangular Enclosure ◽  
Sound Structure ◽  
Flexible Panel ◽  
Experimental Works ◽  
Element Method

Vibration of structures due to external sound is one of the main causes of interior noise in cavities like automobile, aircraft, and rotorcraft, which disturb the comfort of passengers. Accurate modelling of such phenomena is required in eigenfrequency analysis and in designing an active noise control system to reduce the interior noise. In this paper, the effect of periodic noise travelling into a rectangular enclosure is investigated with finite element method (FEM) using COMSOL Multiphysics software. The periodic acoustic wave is generated by a point source outside the enclosure and propagated through the enclosure wall and excites an aluminium flexible panel clamped onto the enclosure. The behaviour of the transmission of sound into the cavity is investigated by computing the modal characteristics and the natural frequencies of the cavity. The simulation results are compared with previous analytical and experimental works for validation and an acceptable match between them were obtained.

scholarly journals Dynamics Characteristics of Blast Furnace Shell

2011 ◽  
Vol 2-3 ◽  
pp. 1018-1020
Author(s):  
De Chen Zhang ◽  
Yan Ping Sun
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Blast Furnace ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Theoretical Foundation ◽  
Structural Mechanics ◽  
Mode Shapes ◽  
The Future ◽  
Element Method

Finite element method and structural mechanics method are used to study the blast furnace shell modal analysis and the natural frequencies and mode shapes have been calculated. The two methods were compared and validated , and the results provide a theoretical foundation for the anti-vibration capabilities design of blast furnace shell in the future .

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