Experimental and Finite Element Modal Analysis of a Pliant Elastic Membrane for Micro Air Vehicles Applications

2012 ◽  
Vol 79 (2) ◽  
Author(s):  
Uttam Kumar Chakravarty ◽  
Roberto Albertani
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Vacuum Chamber ◽  
Natural Frequencies ◽  
Ambient Pressure ◽  
Micro Air Vehicles ◽  
Added Mass ◽  
Elastic Membrane ◽  
Tension Level ◽  
Air Vehicles

This paper investigates the modal characteristics of a latex membrane for micro air vehicles applications. Finite element (FE) models are developed for characterizing the latex membrane at dynamic loading and validated by experimental results. The membrane at different pre-tension levels is attached to a circular steel ring, mounted on a shaker, and placed inside the vacuum chamber for modal characterization using a scanning laser Doppler vibrometer (LDV). The experimental modal analysis is conducted by imposing a structural excitation to the ring for investigating the membrane vibration characteristics at both atmospheric and reduced pressures in a vacuum chamber. FE models are developed for the natural frequencies of the membrane at different uniform and non-uniform pre-tension levels with the effect of the added mass of air. The Mooney-Rivlin hyperelastic material model is selected for the membrane. The natural frequencies of the membrane computed by experimental and FE models are correlated well, although discrepancy is expected among experimental and FE results within reasonable limits due to the variation of the thickness of the membrane. The natural frequencies increase with the mode and pre-tension level of the membrane but decrease due to an increase in ambient pressure. The damping ratios have very minimal effect on the frequencies due to low values but help to reduce the amplitude of vibration. Natural frequencies of the membrane do not change with the uniform and non-uniform nature of the pre-tension, although they increase with the pre-tension level. It is also found that the effect of added mass on the natural frequencies increases with an increase of the size of the membrane specimen.

Finite Element Modeling and Modal Analysis of Coilable Mast

2012 ◽  
Vol 226-228 ◽  
pp. 299-302
Author(s):  
Jie Wang ◽  
Dong Xu Li ◽  
Jian Ping Jiang
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Space Mission ◽  
Joint Model ◽  
Finite Element Models ◽  
Attached Mass ◽  
Element Modeling ◽  
Tension Level

This paper investigates the modal characteristics of a coilable mast for space mission applications. Finite element models are established for characterizing the coilable mast. The simplification of joints between longerons and batten frames and the pre-tension in cables are carefully considered. A parametric modal analysis is performed with considering the following factors, the joint model in the truss, the pre-tension in cables, elements selected for longerons and battens, the mass attached to the top of the mast. Research results show that the natural frequencies of the coilable mast are sensitive to the selected elements and the attached mass. The pre-tension level in cables and the precision degree of the joint model have little effect on natural frequencies. The regularity expressed in the parametric modal analysis is useful for designers and engineers.

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 .

Experimental Identification Approach of Dynamic Parameters of Precise Horizontal Machining Centre Based on Component-System

2011 ◽  
Vol 467-469 ◽  
pp. 1686-1690
Author(s):  
Zhi Feng Liu ◽  
Zhong Hua Chu ◽  
Qiang Cheng ◽  
Guang Bo Liu ◽  
Dong Sheng Xuan
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Modal Testing ◽  
Element Calculation ◽  
Element Simulation ◽  
Modes Of Vibration ◽  
Identification Approach ◽  
Comparison Of The Results ◽  
Machine Structure

This paper integrates experiment modal analysis and the analytical modal analysis to study on the vibration phenomena occurring occasionally at the different components of a precise horizontal machining centre. The paper is focused on extracting the mode shape of the major components of the machine in order to ensure resonance phenomena as a cause of vibration. At first the main natural frequencies with the corresponding modes of vibration of the machine structure are obtained by the experiment modal analysis. Then the dynamic behavior of the machine components is simulated using a finite element simulation model. The comparison of the results based on finite element calculation with their experimental counterparts shows the reasonableness. The model is evaluated and corrected with experimental results by modal testing of the machine components.

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.

Parametric Design and Modal Analysis on Four-Order Elliptical Gear

2013 ◽  
Vol 423-426 ◽  
pp. 1516-1519
Author(s):  
Zhi Dong Huang ◽  
An Min Hui ◽  
Guang Yang ◽  
Rui Yang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Response ◽  
Modal Analysis ◽  
Dynamic Model ◽  
Natural Frequencies ◽  
Parametric Design ◽  
Three Dimensional ◽  
Response Analysis ◽  
Dynamic Design

The characteristics of four-order elliptical gear is analyzed. The parameters of four-order elliptical gear are chosen and calculated. The three-dimensional solid modeling of four-order elliptical gear is achieved. The dynamic model of four-order elliptical gear is established by finite element method and modal analysis of four-order elliptical gear is investigated. The natural frequencies and major modes of the first six orders are clarified. The method and the result facilitate the dynamic design and dynamic response analysis of high-order elliptical gear.

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 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 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.

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