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 Using Implicit Boundary Finite Element Methods

2014 ◽  
Author(s):  
Zhiyuan Zhang ◽  
Ashok V. Kumar
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
B Spline ◽  
Boundary Method ◽  
Mass Matrices ◽  
Background Mesh ◽  
The Given

Modal analysis is widely used for linear dynamic analysis of structures. The finite element method is used to numerically compute stiffness and mass matrices and the corresponding eigenvalue problem is solved to determine the natural frequencies and mode shapes of vibration. Implicit boundary method was developed to use equations of the boundary to apply boundary conditions and loads so that a background mesh can be used for analysis. A background mesh is easier to generate because the elements do not have to conform to the given geometry and therefore uniform regular shaped elements can be used. In this paper, we show that this approach is suitable for modal analysis and modal superposition techniques as well. Furthermore, the implicit boundary method also allows higher order elements that use B-spline approximations. Several test examples are studied for verification.

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.

scholarly journals Modal analysis of an iced offshore composite wind turbine blade

2021 ◽  
pp. 0309524X2110116
Author(s):  
Oumnia Lagdani ◽  
Mostapha Tarfaoui ◽  
Mourad Nachtane ◽  
Mourad Trihi ◽  
Houda Laaouidi
Keyword(s):  
Wind Turbine ◽  
Modal Analysis ◽  
Turbine Blade ◽  
Natural Frequencies ◽  
Wind Turbine Blade ◽  
Resonance Phenomenon ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
Numerical Work ◽  
Composite Blades

In the far north, low temperatures and atmospheric icing are a major danger for the safe operation of wind turbines. It can cause several problems in fatigue loads, the balance of the rotor and aerodynamics. With the aim of improving the rigidity of the wind turbine blade, composite materials are currently being used. A numerical work aims to evaluate the effect of ice on composite blades and to determine the most adequate material under icing conditions. Different ice thicknesses are considered in the lower part of the blade. In this paper, modal analysis is performed to obtain the natural frequencies and corresponding mode shapes of the structure. This analysis is elaborated using the finite element method (FEM) computer program through ABAQUS software. The results have laid that the natural frequencies of the blade varied according to the material and thickness of ice and that there is no resonance phenomenon.

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 .

Modal Analysis of Flexible Assembling Fixture for Aircraft Panel Component

2010 ◽  
Vol 97-101 ◽  
pp. 3392-3396
Author(s):  
Li Gang Qu ◽  
Ke Qiang Pan ◽  
Xin Chen
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Characteristic ◽  
Natural Frequencies ◽  
Great Influence ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Dynamic Vibration ◽  
Structural Weakness ◽  
Modal Vibration

The dynamic characteristic of flexible assembling fixture (FAF) for aircraft panel component is analysed by the method of finite element modal analysis. Consequently, the every order of natural frequencies and mode shapes of given different postures of the FAF are obtained. It structural weakness were pointed out through the analysis results of the modal vibration characteristics. The properties of mass and stiffness of the FAF's components are concurrently calculated, whose optimal matching and harmonizing with each other have great influence on the dynamic vibration characteristics of the FAF. As the results of these analysis, the design improving suggestion for the FAF is put forward.

Free vibration analysis of a rectangular plate carrying multiple various concentrated elements

2003 ◽  
Vol 217 (2) ◽  
pp. 171-183 ◽  
Author(s):  
J-S Wu ◽  
H-M Chou ◽  
D-W Chen
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Rectangular Plate ◽  
Normal Mode ◽  
Vibration Analysis ◽  
Natural Frequencies ◽  
Free Vibration Analysis ◽  
Equation Of Motion ◽  
Mode Shapes

The dynamic characteristic of a uniform rectangular plate with four boundary conditions and carrying three kinds of multiple concentrated element (rigidly attached point masses, linear springs and elastically mounted point masses) was investigated. Firstly, the closed-form solutions for the natural frequencies and the corresponding normal mode shapes of a rectangular ‘bare’ (or ‘unconstrained’) plate (without any attachments) with the specified boundary conditions were determined analytically. Next, by using these natural frequencies and normal mode shapes incorporated with the expansion theory, the equation of motion of the ‘constrained’ plate (carrying the three kinds of multiple concentrated element) were derived. Finally, numerical methods were used to solve this equation of motion to give the natural frequencies and mode shapes of the ‘constrained’ plate. To confirm the reliability of previous free vibration analysis results, a finite element analysis was also conducted. It was found that the results obtained from the above-mentioned two approaches were in good agreement. Compared with the conventional finite element method (FEM), the approach employed in this paper has the advantages of saving computing time and achieving better accuracy, as can be seen from the existing literature.

Modal Analysis Based on Finite Element Jaw Crusher Rotor

2014 ◽  
Vol 599-601 ◽  
pp. 547-550
Author(s):  
Mei Ling Hao ◽  
Guang Juan Cheng
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Weak Link ◽  
Three Dimensional ◽  
Mode Shapes ◽  
Complex Dynamic ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Analysis Of Results

The vertical shaft impact crusher the material is accelerated , while the rotor bear complex dynamic loads , finite element method for three-dimensional modeling of the rotor body and modal analysis , discussion and analysis of results. Won the first 20 natural frequencies and mode shapes , as well as the weak link parts may exist , making the crusher prone resonance attention away from the source at work , as well as designers kinetic design provides some guidance basis.

scholarly journals Dynamic Characteristics of an Elastic Structure with Thermal Effects

2020 ◽  
Vol 25 (2) ◽  
pp. 200-208
Author(s):  
Guanhua Xu ◽  
Jianzhong Fu ◽  
Wen He ◽  
Yuetong Xu ◽  
Zhiwei Lin ◽  
...  
Keyword(s):  
Modal Analysis ◽  
Dynamic Characteristics ◽  
Thermal Effects ◽  
Natural Frequencies ◽  
Elastic Structure ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
Environmental Testing ◽  
Temperature Changes ◽  
Property Changes

The vibration table in a combination environmental testing device suffers from temperature changes, which cause the dynamic characteristics of the vibration structure to vary. The mechanism of the thermal effect on the dynamic characteristics of an elastic structure is presented, and a modal analysis with thermal effects based on the finite-element method (FEM) is carried out. The results show that the natural frequencies for each order decrease as the temperature increases, while the mode shapes of the vibrator do not change with temperature. Although thermal stress may affect natural frequencies due to the additional initial stress element stiffness, this stress can be neglected in the modal analysis because it is negligible relative to the effect of the material property changes with temperature.

scholarly journals Rayleigh Damping Coefficients of Laminated Rubber Bearing

2019 ◽  
Vol 8 (4) ◽  
pp. 12294-12300
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Experimental Modal Analysis ◽  
Mode Shapes ◽  
Ground Structure ◽  
Damping Coefficients ◽  
Rubber Bearing ◽  
Stability And Instability ◽  
Laminated Rubber Bearing

In isolating the ground structure and the above ground structure from seismic loads, a significant device called laminated rubber bearing is usually found in structure. The complexity of the material which is made up from a combination of rubber and steel shim plates in alternate layer, has made it difficult to measure damping value. Damping is a dissipation of energy or energy losses in the vibration of the structure. Measuring the accurate amount of damping is fundamental as damping plays a crucial role in fixing the borderline between stability and instability in structural systems. Therefore, to determine the damping value including dynamic properties in any materials, modal analysis can be used. Hence, the main objective of this research is to determine the Rayleigh’s damping coefficients α and β and to evaluate the performance of the laminated rubber bearing using finite element and experimental modal analysis. Finding shows that, the finite element modal analysis with the addition of Rayleigh’s damping coefficients α and β, shows a good agreement with the experimental modal analysis in term of natural frequencies and mode shapes. Findings show that, the values of natural frequencies reduced when precise Rayleigh’s damping coefficient added in the finite element modal analysis. It can be concluded that both finite element and experimental modal analysis method can be used to estimate the accurate values of damping ratio and to determine the Rayleigh’s damping coefficients α and β as well.

scholarly journals Transverse Vibration of Stiffened Plates with Cutouts Subjected to In-Plane Uniform Edge Loading at the Plate Boundary

2004 ◽  
Vol 11 (1) ◽  
pp. 9-19 ◽  
Author(s):  
A.K.L. Srivastava ◽  
P.K. Datta ◽  
A.H. Sheikh
Keyword(s):  
Natural Frequencies ◽  
Plate Boundary ◽  
Mode Shapes ◽  
Stiffened Plates ◽  
Plate Boundaries ◽  
The Finite Element Method ◽  
Edge Loading ◽  
Plate Width ◽  
Clamped Edge ◽  
Good Agreement

Vibration characteristics of stiffened plates with cutouts subjected to uni-axial in-plane uniform edge loading at the plate boundaries are investigated using the finite element method. The characteristic equations for the natural frequencies, buckling loads and their corresponding mode shapes are obtained from the equation of motion. The vibration frequencies and buckling load parameters for various modes of stiffened plates with cutouts have been determined for simply supported and clamped edge boundary conditions. In the structure modelling, the plate and the stiffeners are treated as separate elements where the compatibility between these two types of elements is maintained. Numerical results are presented for a range of hole to plate width ratios of 0 to 0.8. The correlations of the natural frequencies and buckling parameters obtained by the present approach with those available in the literature are found to show good agreement.

Sign in / Sign up

Export Citation Format

Share Document