Improved Results in Structural Dynamic Calculations by Linking Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA)

1995 ◽  
Author(s):  
Ulrich Gabbert ◽  
Manfred Zehn ◽  
Friedrich Wahl
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Numerical Models ◽  
Mass Matrix ◽  
Computer Time ◽  
Experimental Modal Analysis ◽  
Mode Shapes ◽  
Element Analysis ◽  
Structural Dynamic

Abstract The paper deals with improvements of accuracy of structural dynamic calculations by using both the advantages of Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA). The basis for such improvements are reasonable mechanical and numerical models and accurate frequency response measurements (eigenfrequencies and mode shapes). The paper deals first with reasons for and estimations of errors in numerical and experimental analysis. It can be shown by theory and experiment that neither FEA nor EMA models are unique, due to inevitable incompleteness of the mode shapes and eigenfrequencies from a vibration test. Verification and updating of FE models by linking FEA with EMA are discussed in the paper and mainly focussed on FE models with a large number of degrees of freedom. Hence an update method has been introduced, which leads to an improved model in a relatively small quantity of computer time. It can be shown, that based on measured eigenfrequencies and calculated eigenvectors, an updating of FE-models for real engineering problems, by changing the mass matrix only, is a very efficient procedure with a surprisingly good quality updated model.

Dynamic Characterization of Car Door and Hood Panels Using FEA and EMA

2013 ◽  
Vol 471 ◽  
pp. 89-96 ◽  
Author(s):  
Zahir Hanouf ◽  
Waleed F. Faris ◽  
Mohd Jailani Mohd Nor
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Properties ◽  
Experimental Modal Analysis ◽  
Modal Testing ◽  
Dynamic Characterization ◽  
Element Analysis ◽  
Structural Dynamic

The dynamic characterization of vehicle structures is a crucial step in NVH analysis and helps in refining the vibration and noise in new vehicles. This paper investigates the dynamic properties of two parts of the vehicle structure which are door and hood panels. Theoretical modal analysis which is referred to as Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA) or modal testing has been used as investigative tools. The paper investigates the structural dynamic properties of door and hood panels of a local car. ME'scope software was used to analyze the data obtained from Pulse to extract the dynamic properties of the panels. LS-DYNA software was used to analyze the dynamic behavior of the structure. The comparison between the results obtained from both analyses showed some similarity in frequencies and mode shapes. Finally the paper concludes that experimental modal analysis and finite element analysis can both be used to extract dynamic properties of structures.

Based on 3D Virtual Prototype Technology and Finite Element Analysis of the Optimization of the Automobile Front Axle

2014 ◽  
Vol 684 ◽  
pp. 330-334
Author(s):  
Heng Yi Yuan ◽  
Ming Wang He
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Impact Load ◽  
Load Condition ◽  
Front Axle ◽  
Mode Shapes ◽  
Element Analysis ◽  
Emergency Braking ◽  
The Impact

The front axle is an important part of a car, directly affects the dynamic characteristics of car. Based on UG NX6.0 for automobile front axle parts 3D modeling, finite element analysis software ANSYS modal analysis was carried out on the front axle, and extract their first four order natural frequency and vibration mode shapes, the automobile front axle structure stress analysis and stress distribution nephogram of get parts. Analysis of the impact load condition and emergency braking conditions modal analysis, and further to fatigue analysis of the front axle bridge shell, for provide valuable reference data for the reasonable design of parts. For the kinetics of further research and improvement of front axle provides the theoretical basis, but also provides reference to the actual test.

Study of Passive Vibration Absorbers Attached on Beam Structure

2014 ◽  
Vol 660 ◽  
pp. 511-515 ◽  
Author(s):  
Izzuddin Zaman ◽  
Muhammad Mohamed Salleh ◽  
Maznan Ismon ◽  
Bukhari Manshoor ◽  
Amir Khalid ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequency ◽  
Structural Vibration ◽  
Mode Shapes ◽  
Small Scale ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Element Analysis ◽  
Structural Dynamic

Structural vibration is undesirable, wasting energy and possibly leading to excessive deflections and structure and machine’s failure. In order to reduce structural vibration, one of the common way is considering vibration absorber system attach to the structure. In this study, a vibration absorber is developed in a small scale size. The host structure selected for the study is a fixed-fixed ends beam. The effectiveness of vibration absorbers attached to a beam is investigated through experimental study. In prior to experiment, a finite element analysis of Solidworks® and analytical equations of Matlab® are produced in order to determine the structural dynamic response of the beam, such as the natural frequency and mode shapes. The preliminary results of finite element analysis demonstrate that the first five natural frequency of fixed-fixed end beam are 17Hz, 46Hz, 90Hz, 149Hz and 224Hz, and these results are in agreement with the beam’s analytical equations. However, there are slight discrepancies in experiment result due to noise and error occurred during the setup. In the later stage, the experimental works of beam are performed with attached vibration absorber. Result shows that the attachment of vibration absorber produces better outcome, which is about 45% vibration reduction. It is expected that by adding more vibration absorber to the structure, the vibration attenuation can significant.

scholarly journals Modal Analysis of Optimized Trapezoidal Stiffened Plates under Lateral Pressure and Uniaxial Compression

2021 ◽  
Vol 2 (4) ◽  
pp. 681-693
Author(s):  
Zoltán Virág ◽  
Sándor Szirbik
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Uniaxial Compression ◽  
Natural Frequencies ◽  
Lateral Pressure ◽  
Mode Shapes ◽  
Stiffened Plates ◽  
Elastic Model ◽  
Element Analysis

This paper deals with the modal analysis of optimized trapezoidal stiffened plates with simple supported conditions on the four edges of the base plate. The main objective of the finite element analysis is to investigate the natural frequencies and mode shapes of some stiffened structures subjected to lateral pressure and uniaxial compression in order to identify any potentially dangerous frequencies and eliminate the failure possibilities. The natural frequencies and mode shapes are important parameters in the design of stiffened plates for dynamic loading conditions. In this study, the numerical analysis is performed for such a design of this kind of welded plates which have already been optimized for lateral pressure and uniaxial compression. The objective function of the optimization to be minimized performed with the Excel Solver program is the cost function which contains material and fabrication costs for Gas Metal Arc Welding (GMAW) welding technology. In this study, the eigenvalue extraction used to calculate the natural frequencies and mode shapes is based on the Lanczos iteration methods using the Abaqus software. The structure is made of two grades of steel, which are described with different yield stress while all other material properties of the steels in the isotropic elastic model remain the same. Drawing the conclusion from finite element analysis, this circumstance greatly affects the result.

The Application of Multiple Vibration Neutralizers for Vibration Control in Aircraft

2014 ◽  
Vol 629 ◽  
pp. 191-196 ◽  
Author(s):  
Izzuddin Zaman ◽  
Muhammad Mohamed Salleh ◽  
Bukhari Manshoor ◽  
Amir Khalid ◽  
Sherif Araby
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Vibration Control ◽  
Natural Frequency ◽  
Thin Plate ◽  
Mode Shapes ◽  
Modern Trend ◽  
Small Scale ◽  
Element Analysis ◽  
Structural Dynamic

A current challenge for researchers is the design and implementation of an effective vibration control method that reduces vibration transmission from vehicle structures such as aircraft. This challenge has arisen due to the modern trend of utilizing lightweight thin panels in aircraft structural design, which have the potential to contribute towards significant vibration in the structures. In order to reduce structural vibration, one of the common approaches is considering vibration neutralizer system attached to the structure. In this study, a vibration neutralizer is developed in a small scale size. The effectiveness of attached vibration neutralizers on a thin plate are investigated through experimental study. Prior to the experiment, a finite element analysis of Solidworks® and analytical modelling of Matlab® are produced in order to determine the structural dynamic response of the thin plate such as the natural frequency and mode shapes. The preliminary results of finite element analysis demonstrate that the first four natural frequency of clamped plate are 48Hz, 121Hz, 194Hz and 242Hz, and these results are in agreement with the plate’s analytical equations. However, there are slight discrepancies in the experiment result due to noise and error occurred during the set up. In the later stage, the experimental works of thin plate are performed with attached vibration neutralizer. Result shows that the attachment of vibration neutralizer produces better outcome, which is about 41% vibration reduction. It is expected that by adding more vibration neutralizer to the structure, the vibration attenuation of thin plate can be significant.

A finite element analysis of idealized damage in beam structures

2004 ◽  
Vol 218 (9) ◽  
pp. 921-929 ◽  
Author(s):  
K A Alnefaie
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Strain Energy ◽  
Damage Index ◽  
Experimental Modal Analysis ◽  
Element Analysis ◽  
Beam Structures ◽  
Sensitive Parameter ◽  
Moment Index

The strain energy damage index (SEDI) and a nominally similar parameter called SEDI2 are reported to be insensitive to the magnitude of the underlying damage in beams, although they do help to locate the damage itself. A new damage-sensitive parameter, the modal moment index (MMI), is introduced. It is shown that the MMI also ‘jumps’ at the location of damage in the beam. In addition, it is established that the magnitude of the MMI is closely related to the decrease in relative modulus. It is concluded hence that the MMI seems to be a damage-sensitive parameter with potential for application in experimental modal analysis.

Experimental Modal Analysis and Modal Reproduce Experiment Research of a Chladini Plate

2012 ◽  
Vol 152-154 ◽  
pp. 1401-1405
Author(s):  
Xun Ma ◽  
Ji Wei Zhang ◽  
Shi Ming Yan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Experimental Research ◽  
Experimental Modal Analysis ◽  
Acoustic Excitation ◽  
Experiment Research ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Ansys Workbench

By means of ANSYS Workbench, different materials, dimensions and shapes of the Chladni plates are simulated. The natural frequency and Modal are obtained so that the chladni plate is determined and manufactured, that is used in the experimental research. Then, modal analysis test is conducted by Experimental modal analysis, the resonance and modal characteristics of the plate between 1Hz to 1000Hz are identified. Finally, Modal reproduce experiment is conducted under the acoustic excitation. Experimental and analytical results show that the finite element analysis, experimental modal analysis and Modal reproduce experiment basically have the same results.

Modal Analysis of Bus Body Structure using Finite Element Analysis Technique

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Vikas Radhakrishna Deulgaonkar ◽  
M.S. Kulkarni ◽  
S.S. Khedkar ◽  
S.U. Kharosekar ◽  
V.U. Sadavarte
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Mode Shapes ◽  
Body Structure ◽  
Element Analysis ◽  
Industry Standards ◽  
Analysis Technique ◽  
Bus Body ◽  
Good Agreement

Present work deals with evaluation of dynamic characteristics of a bus body structure. The bus under consideration is a sleeper non-air conditioned vehicle for a passenger capacity of thirty and it is designed adhering to automotive industry standards. Modal analysis of the proposed bus design is carried using Ansys Workbench. With the aid of modal analysis ten mode shapes of the bus are postulated, corresponding frequencies and deflections are estimated. Mesh generator is used to mesh the complex bus model. The deflection and frequency magnitudes of proposed bus model is found with the help of Finite Element Analysis (FEA) technique and they are in good agreement with experimental results available in literature. Engine being the prime source of excitation, it’s frequency is compared with the frequencies determined by FEA of the proposed bus body and it is observed that the frequencies of the bus body for ten different modes are far less than the minimum resonant engine frequency.

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