scholarly journals Identifying the Appropriate Frequency Response Function Driving Point of a Car Door Using Finite Element Analysis and Modal Testing

2019 ◽  
Vol 1262 ◽  
pp. 012007
Author(s):  
W I I Wan Iskandar Mirza ◽  
M N Abdul Rani ◽  
M F Musa ◽  
M A Yunus ◽  
C Peter ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Modal Testing ◽  
Element Analysis

Change of modal parameters due to crack growth in a tripod tower platform

1993 ◽  
Vol 20 (5) ◽  
pp. 801-813 ◽  
Author(s):  
Yin Chen ◽  
A. S. J. Swamidas
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Experimental Results ◽  
Modal Testing ◽  
Modal Parameters ◽  
Response Functions ◽  
Frequency Response Functions ◽  
Strain Frequency

Strain gauges, along with an accelerometer and a linear variable displacement transducer, were used in the modal testing to detect a crack in a tripod tower platform structure model. The experimental results showed that the frequency response function of the strain gauge located near the crack had the most sensitivity to cracking. It was observed that the amplitude of the strain frequency response function at resonant points had large changes (around 60% when the crack became a through-thickness crack) when the crack grew in size. By monitoring the change of modal parameters, especially the amplitude of the strain frequency response function near the critical area, it would be very easy to detect the damage that occurs in offshore structures. A numerical computation of the frequency response functions using finite element method was also performed and compared with the experimental results. A good consistency between these two sets of results has been found. All the calculations required for the experimental modal parameters and the finite element analysis were carried out using the computer program SDRC-IDEAS. Key words: modal testing, cracking, strain–displacement–acceleration frequency response functions, frequency–damping–amplitude changes.

Machine Gun Finite Element Model Amending Based on Frequency Response Functions of Vibration

2014 ◽  
Vol 599-601 ◽  
pp. 349-352 ◽  
Author(s):  
Ben Li Wang ◽  
Zi Wei Dong
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Model Updating ◽  
Element Model ◽  
Correction Method ◽  
Modal Testing ◽  
Model Correction

Correction machine gun finite element model to predict dynamic characteristics is very important. Through theoretical calculations and experimental test structure to obtain guns frequency response function, given the sensitivity of both the correlation function and expression, introduced a model correction method, and laid the theoretical foundation for a certain type of machine gun finite element model updating. Build a certain type of machine guns and modal testing and analysis system was carried out to test the vibration frequency response function. Boundary condition parameters of the machine gun was amended, and modal test results were compared to prove the validity of the model correction method.

scholarly journals FINITE ELEMENT ANALYSIS OF CENTRELESS-LUNETTE TURNING OF HEAVY SHAFT

2017 ◽  
Vol 16 (3) ◽  
pp. 196-205
Author(s):  
Yu. V. Vasilevich ◽  
S. S. Dounar
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Polymer Concrete ◽  
Element Analysis ◽  
Support Tool ◽  
Near Resonance ◽  
Dynamic Damping ◽  
It Support ◽  
Concrete Filling

Dynamics of huge renovated lathe is simulated. Turning scheme concerns to heavy rotor shaft finishing. Lofty parts and milling head may create dynamic problems. Static, modal and harmonic frequency response function simulations were provided. Bearing system consists of bed, support, tool, lunettes, tailstock. Headstock didn’t take part in shaft holding. Static and dynamic rigidities founded 3–4 times less for support than for shaft. Tool rigidity lessens from 186.5 to 11.9 N/µm for speeding from slow to near resonance turning. Twelve lathe eigenmodes were evaluated. Two eigenmodes are most dangerous. It is “shaft swinging on lunettes” (M1, 26.7 Hz) and “support pecking” (M3, 54.4 Hz). Bed has excessive flexibility due to through holes and lack of inner ribbing. Polymer concrete filling is moderately effective. Changing two-lunette (2L) scheme to three-lunette (3L) increases rigidity of shaft at 2.09 times at statics but gives limited action in dynamics. Resonant peaks on frequency response function are lowered only at 1.32 times for M1, M3. Effect of dynamic damping is revealed under condition of proximity middle lunette to lofty support. Support serves as tuned mass damper. Measures of machine tool reinforcement are simulated. Shaft swinging according to M1 may hardly be blocked by passive means. It would be better to bypass it. “Support pecking” resonance (M3) succumbs to only full set of measures. Small effect of partial reinforcement is predicted. Three frequency intervals are recommended for turn-milling at huge lathe: pre-resonant (<20 Hz), inter-resonant (35–45 Hz) and post-resonant (>65 Hz). The last one is more suited. Next design step is to create triangle inner ribbing system or caissons inside of bed.

Identification of Rotating Asymmetry in Rotating Machines by Using Reverse dFRF

1999 ◽  
Author(s):  
Chong-Won Lee ◽  
Kye-Si Kwon
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Modal Testing ◽  
Vibration Sensor ◽  
Response Functions ◽  
Physical Realization ◽  
Simple Method ◽  
Testing Method ◽  
Asymmetric Rotor

Abstract A quick and easy but comprehensive identification method for asymmetry in an asymmetric rotor is proposed based on complex modal testing method. In this work, it is shown that the reverse directional frequency response function (reverse dFRF), which indicates the degree of asymmetry, can be identified with a simple method requiring only one vibration sensor and one exciter. To clarify physical realization associated with estimation of the reverse dFRF, its relation to the conventional frequency response functions, which are defined by the real input (exciter) and output (vibration sensor), are extensively discussed.

The Efficient Multi-Objective Optimization of Finite Element Analysis Model Using ModelCenter

2016 ◽  
Author(s):  
Lyu Wang ◽  
Yuan Yun ◽  
Bin Zhang ◽  
Tao Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Frequency Response ◽  
Space Environment ◽  
Multi Objective Optimization ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
Multi Objective ◽  
Software Analysis

The multi-objective optimization for a nested flying vehicle (NFV) of space science experiments is carried out aiming at the launch weight, frequency response and vacuum effect. The parametric model and finite element analysis are adopted to implement the structural analysis. The NFV is optimized to enhance the performance in the space environment where the lunch weight and structural strength are key constraints to concern about. The CAX software, analysis models and algorithms are integrated based on ModelCenter framework which makes modeling, analyzing and optimization more convenient and efficient. The optimizer of ModelCenter is chosen to optimize the structural performance of NFV, including the total mass, maximum deformation caused by vacuum environment and frequency response. As to validate the results, both weighting method with gradient optimization algorithm and Genetic Algorithm (GA) for multi-objective optimization are used. The optimization results of NFV verify the approaches proposed in this paper can improve the performance of NFV and apply to the finite element analysis model.

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