Analysis of the Dynamic Response of a Cracked Beam Structure

2012 ◽  
Vol 187 ◽  
pp. 58-62 ◽  
Author(s):  
D. N. Thatoi ◽  
J. Nanda ◽  
H.C. Das ◽  
D.R. Parhi
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Cantilever Beam ◽  
Crack Detection ◽  
Dynamic Behaviour ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Cracked Beam ◽  
Local Flexibility ◽  
Good Agreement

In this research, dynamic behaviour of a cracked cantilever beam has been analysed using finite element and experimental analysis. Deviations in mode shapes and natural frequencies have been noticed due to the presence of crack in the beam. The variation in the dynamic response is due to change in local flexibility because of the presence of crack in the beam. Finite element and experimental analyses have been carried out to find out the vibration indices of the cracked cantilever beam for validating the robustness of the theoretical model used for crack detection. The numerical results obtained through FEA are in good agreement with experimental results.

scholarly journals Rayleigh's quotient for multiple cracked beam and application

2011 ◽  
Vol 33 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Nguyen Tien Khiem ◽  
Tran Thanh Hai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Analysis ◽  
Crack Detection ◽  
Natural Frequencies ◽  
Shape Function ◽  
Detection Problem ◽  
Cracked Beam ◽  
Rayleigh’S Quotient ◽  
Good Agreement

Rayleigh's quotient for Euler-Bernoulli multiple cracked beam with different boundary conditions has been derived from the governed equation of free vibration. An appropriate choosing of approximate shape function in terms of mode shape of uncracked beam and specific functions satisfying conditions at cracks and boundaries leads to an explicit expression of natural frequencies through crack parameters that can simplify not only the analysis of natural frequencies of cracked beam but also the crack detection problem. Numerical analysis of natural frequencies of the cracked beam by using the obtained expression in comparison with the well-known methods such as the characteristic equation and finite element method shows their good agreement. The analytical expression of natural frequencies applied to the crack detection problem allows the result of detection to be improved.

scholarly journals Modal Analysis of Orthotropic Thin Rectangular Plate Based on Analytical and Finite Element Approaches

2020 ◽  
Vol 30 (5-6) ◽  
pp. 217-225
Author(s):  
Samir Deghboudj ◽  
Wafia Boukhedena ◽  
Hamid Satha
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Rectangular Plate ◽  
Analytical Approach ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Geometrical Parameters ◽  
The Finite Element Method ◽  
Thin Rectangular Plate ◽  
Good Agreement

The present work aims to carry out modal analysis of orthotropic thin rectangular plate to determine its natural frequencies and mode shapes by using analytical method based on Rayleigh-Ritz energy approach. To demonstrate the accuracy of this approach, the same plate is discritisated and analyzed using the finite element method. The natural and angular frequencies were computed and determined analytically and numerically by using ABAQUS finite element code. The convergency and accuracy of the numerical solution was examined. The effects of geometrical parameters and boundary conditions on vibrations are investigated. The results obtained showed a very good agreement between the analytical approach and the numerical simulations. Also, the paper presents simulations results of testing of the plate with passive vibration control.

Modal Analysis of the Cabinet of a Drum Washing Machine

2011 ◽  
Vol 199-200 ◽  
pp. 1126-1129
Author(s):  
Su Fang Fu ◽  
Han Gao ◽  
Jia Xi Du ◽  
Qiu Ju Zhang ◽  
Xue Ming Zhang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Element Model ◽  
Mode Shapes ◽  
Ansys Software ◽  
Washing Machine ◽  
Element Analysis ◽  
The Finite Element Model ◽  
Good Agreement

In this paper, the finite element model for the cabinet of a drum washing machine and the model for testing vibration of the cabinet were developed in ANSYS software and PULSE™, respectively. A series of tests were conducted. The natural frequencies and mode shapes were obtained by finite element analysis and modal experiment, which revealed weak parts of the cabinet. Meanwhile, the computational modes were in good agreement with experimental ones and this could provide an available method by which it was convenient to improve the design of the cabinet.

Dynamic Response Analysis of Motorcycle Fenders

2014 ◽  
Vol 541-542 ◽  
pp. 695-699
Author(s):  
Jun Liu ◽  
Liang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Dynamic Response ◽  
Key Words ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Response Analysis ◽  
Structure Modeling ◽  
Main Components

Motorcycle fender is one of the main components of motorcycle,fender structure directly affected it's comfort and security properties.In this paper, the finite element modeling and dynamic response were analyzed using NX 8.0, and found its natural frequencies and mode shapes. On the basis of the fender structure modeling on different road with the same speed, this paper investigated the several factors affect the vibration motorcycle and analyzed true fender of the motorcycle and did comparative analysis with the modal analysis results. It is helpful to the design of the fender structure and the estimation of the fender fracture. Key Words: Fender;finite element method;modal;Dynamic response

scholarly journals Dynamic Behaviour Analysis of Optical Linear Encoder under Mechanical Vibrations

Mechanika ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 35-41
Author(s):  
Donatas Gurauskis ◽  
Artūras Kilikevičius
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Response ◽  
Machine Tools ◽  
Dynamic Behaviour ◽  
Mode Shapes ◽  
Technological Equipment ◽  
External Excitation ◽  
Mechanical Vibrations ◽  
Linear Encoder

Mechanical vibrations are probably inevitable and occur in more or less all machine tools and other technological equipment. In case the linear encoder is used for moveable parts positioning in such machines, vibrations could cause additional errors. This paper investigates the dynamic behavior of the optical linear encoder under mechanical vibrations. Potentially the most harmful frequencies are determined experimentally, and the corresponding mode shapes are simulated by using finite element method (FEM). Obtained results describe tested encoder`s construction dynamic response to external excitation and could be used to improve its design.

Vibration of the Rotor Shell in a Trochoidal-Type Machine Without Apex Seals

1998 ◽  
Author(s):  
Shuangqing Li ◽  
John B. Shung ◽  
Randall F. Barron
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Dynamic Response ◽  
Analytical Method ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Type Machine ◽  
Element Method

Abstract The natural frequencies and dynamic response of a trochoidal cylindrical shell in a trochoidal-type machine are studied. Both analytical method and finite element method (FEM) solutions are obtained. The mode shapes obtained by the two approaches match quite well. The model established can be applied to control the running clearance between rotor and chamber in this type of machine, which is critical to the performance of the machine.

Follower Effect of Internal Pressure on Modal Analysis of a Space Inflatable Structure

2015 ◽  
Vol 727-728 ◽  
pp. 578-582
Author(s):  
Fei Liu ◽  
Wei Liang He
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Element Model ◽  
Mode Shapes ◽  
Fem Model ◽  
Configuration Change ◽  
Modal Behavior ◽  
Good Agreement ◽  
Inflatable Structure

The stress distribution and modal behavior of a space inflatable torus was investigated by nonlinear finite element numerical method. This paper focused on the effect of follower pressure on the modal analysis of the torus, including the effect of configuration change and follower pressure stiffness, and focused on validating the follower pressure stiffness FEM model and its applicability to modal analysis. Research shows that the changed configuration slightly increases the natural frequencies. The follower pressure stiffness significantly reduces the natural frequencies and changes mode shapes order. The modal results are in good agreement with the corresponding shell theory solutions, indicating that the finite element model of the follower pressure stiffness for the inflatable structure modal analysis in this paper is accurate enough and reasonable.

Vibration Analysis of a Beam with Multiple Cracks

2012 ◽  
Vol 178-181 ◽  
pp. 2505-2508 ◽  
Author(s):  
Chang Li Xiao ◽  
Ling Ling Xu
Keyword(s):  
Stiffness Matrix ◽  
Strain Energy ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Multiple Cracks ◽  
Transverse Cracks ◽  
Cracked Beam ◽  
Strain Energy Density Function ◽  
Natural Frequency Analysis ◽  
Good Agreement

A new method for the natural frequency analysis of a beam with multiple transverse cracks has been carried out. The method is called reverse modal analysis in this paper. The strain energy density function is used to evaluate the additional flexibility produced due to the presence of crack. Based on the flexibility, a new stiffness matrix is deduced and subsequently that is used to calculate the natural frequencies and mode shapes of the cracked beam. It has been established that the crack depths and their positions have an important effect on its dynamic behavior. The analysis of the crack structure is done using finite element and experimental analysis. The results from numerical analysis are compared with the results from the experimental method for validation. The results are found to be in good agreement.

Tire Vibrations

1977 ◽  
Vol 5 (4) ◽  
pp. 202-225 ◽  
Author(s):  
G. R. Potts ◽  
C. A. Bell ◽  
L. T. Charek ◽  
T. K. Roy
Keyword(s):  
Natural Frequencies ◽  
Standing Waves ◽  
Resonant Mode ◽  
Mode Shapes ◽  
Resonant Vibrations ◽  
Resonant Frequencies ◽  
Radial Tire ◽  
Analysis Techniques ◽  
Thin Ring ◽  
Good Agreement

Abstract Natural frequencies and vibrating motions are determined in terms of the material and geometric properties of a radial tire modeled as a thin ring on an elastic foundation. Experimental checks of resonant frequencies show good agreement. Forced vibration solutions obtained are shown to consist of a superposition of resonant vibrations, each rotating around the tire at a rate depending on the mode number and the tire rotational speed. Theoretical rolling speeds that are upper bounds at which standing waves occur are determined and checked experimentally. Digital Fourier transform, transfer function, and modal analysis techniques used to determine the resonant mode shapes of a radial tire reveal that antiresonances are the primary transmitters of vibration to the tire axle.

Dynamic model for high-speed rotors based on their experimental characterization

2017 ◽  
Vol 2 (4) ◽  
pp. 25
Author(s):  
L. A. Montoya ◽  
E. E. Rodríguez ◽  
H. J. Zúñiga ◽  
I. Mejía
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Experimental Characterization ◽  
Rotating Systems ◽  
Computing Performance ◽  
The Impact ◽  
Stiffness Distribution ◽  
Good Agreement

Rotating systems components such as rotors, have dynamic characteristics that are of great importance to understand because they may cause failure of turbomachinery. Therefore, it is required to study a dynamic model to predict some vibration characteristics, in this case, the natural frequencies and mode shapes (both of free vibration) of a centrifugal compressor shaft. The peculiarity of the dynamic model proposed is that using frequency and displacements values obtained experimentally, it is possible to calculate the mass and stiffness distribution of the shaft, and then use these values to estimate the theoretical modal parameters. The natural frequencies and mode shapes of the shaft were obtained with experimental modal analysis by using the impact test. The results predicted by the model are in good agreement with the experimental test. The model is also flexible with other geometries and has a great time and computing performance, which can be evaluated with respect to other commercial software in the future.

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