scholarly journals Evaluation of an Experimental Modal Analysis Device for Micromilling Tools

2021 ◽  
Author(s):  
Joel Martins Crichigno Filho ◽  
Saulo Melotti
Keyword(s):  
Laser Beam ◽  
Modal Analysis ◽  
Laser Doppler Vibrometer ◽  
Force Sensor ◽  
Experimental Modal Analysis ◽  
Modal Testing ◽  
Micro Milling ◽  
Stability Diagrams ◽  
Impulse Duration ◽  
The Impact

Abstract Stable machining conditions in the micromilling process are critical to increase the production of small components. Precise frequency response measurements are essential to generate the stability diagrams. Therefore, impact hammer application which mostly relies on operator's skill and experience is very time-consuming and can produce imprecise results. This study aims to analyze a device developed to perform the experimental modal analysis of micromilling tools. The device facilitates the positioning of a fixed point Laser Doppler Vibrometer ( LDV ) as well as providing automatic and reproductive impact tests. Two mirrors supported by kinematic mounts are used to position the laser beam on the micro milling tool surface. The impact hammer is composed of a force sensor attached to a custom designed flexure-based body, in which an automated electromagnetic releases the mechanism. A set of experiments were conducted to perform the precision positioning of the laser beam and the impact hits. The impact force repeatability in terms of the magnitude and impulse duration were also investigated. The application of the device was demonstrated through modal testing of two micromilling tools with two different diameters.

scholarly journals Experimental Modal Analysis of Violins Made from Composites

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 535 ◽  
Author(s):  
Tim Duerinck ◽  
Mathias Kersemans ◽  
Ewa Skrodzka ◽  
Marc Leman ◽  
Geerten Verberkmoes ◽  
...  
Keyword(s):  
Composite Materials ◽  
Modal Analysis ◽  
Small Difference ◽  
Laser Doppler Vibrometer ◽  
Experimental Modal Analysis ◽  
Laser Doppler ◽  
Breathing Mode ◽  
Vibrational Response

Six prototype violins made from composite materials are made and investigated using experimental modal analysis with the roving hammer method. The average FRF’s obtained show an influence of the materials on the vibrational response up to 2200 Hz. The A0 breathing mode and B1- mode are identified and are found to be significantly lower than in classical wooden violins. Additional measurements with a Laser Doppler Vibrometer and shaker found the same modes with a small difference in frequency (3–8 Hz).

An Experimental Modal Analysis Technique for Miniature Structures

1996 ◽  
Vol 118 (1) ◽  
pp. 1-9 ◽  
Author(s):  
C. J. Wilson ◽  
D. B. Bogy
Keyword(s):  
Modal Analysis ◽  
Laser Doppler Vibrometer ◽  
Element Model ◽  
Experimental Modal Analysis ◽  
Modal Parameters ◽  
Computational Results ◽  
Magnetic Actuator ◽  
Analysis Technique ◽  
Excitation Force ◽  
Analysis System

This paper describes an experimental modal analysis system which can effectively be used to obtain the modal parameters of small structures. The system uses an electromagnetic exciter to produce the excitation force, a piezoelectric transducer to measure this force, and a Laser Doppler Vibrometer to measure the response. Several designs of the magnetic actuator are discussed and evaluated. The system is verified by obtaining the modal parameters of a miniature cantilever plate, using two preferred exciter designs, and comparing the measured parameters with those acquired from a finite element model. Favorable agreement is obtained between the experimental and computational results. Finally, the two preferred exciters are compared and an optimal configuration is discussed.

Modal analysis of violin bodies with back plates made of different wood species

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 7687-7713
Author(s):  
Vasile Ghiorghe Gliga ◽  
Mariana Domnica Stanciu ◽  
Silviu Marian Nastac ◽  
Mihaela Campean
Keyword(s):  
Modal Analysis ◽  
Quality Factor ◽  
Wood Species ◽  
Natural Frequencies ◽  
Musical Instrument ◽  
Experimental Modal Analysis ◽  
Acoustic Properties ◽  
Spectral Components ◽  
The Impact

This research investigated the potential of some European wood species for use in the manufacturing of the back plates of violins as an alternative to the quite rare curly maple wood. An experimental modal analysis was employed for this purpose using the impact hammer method. The modal analysis was performed both on the top and back plates, as individual structures, and then after being integrated into the violin body. The modal analysis envisaged the determination of the eigenfrequencies (natural frequencies), the number of spectral components, and the quality factor, as important indicators of the acoustic performances of a musical instrument. A multi-criteria analysis based on the values obtained for these indicators allowed interesting findings concerning the acoustic properties of the selected wood species (hornbeam, willow, ash, bird-eye maple, walnut, and poplar). Same as curly maple, they all have special aesthetics, but only hornbeam, willow, and ash wood proved to have acoustic potential as well.

scholarly journals Experimental Modal Analysis of Business Jet Fuselage Tail Section Sub-Assemblies

2020 ◽  
Author(s):  
Ian A. Donaldson ◽  
Chris K. Mechefske
Keyword(s):  
Modal Analysis ◽  
Computational Models ◽  
Natural Frequencies ◽  
Model Updating ◽  
Experimental Modal Analysis ◽  
Experimental Results ◽  
Modal Testing ◽  
Experimental Methodology ◽  
Mode Shapes ◽  
Business Jet

Abstract Experimental modal testing is a technique through which the dynamic response of a system can be found. Parameters such as the natural frequencies and mode shapes of a system can be extracted through experimentation, and these results can be used to confirm computational models and guide structural improvements. This paper provides an overview of experimental modal analysis performed on two aircraft fuselage half scale subassemblies, with the use of shaker excitation. The experimental methodology including the construction of each structure, data acquisition parameters, and validity checks, is presented in detail. Linearity and repeatability checks were used to validate the testing methodology and increase the level of confidence in the experimental results. The experimental natural frequencies were correlated with the computational results, and recommendations were made. The experimental results presented in this work provide a basis for computational model updating work to be considered in future work.

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.

A Study on the Vibrational Characteristics of the Continuous Circular Cylindrical Shell with the Multiple Supports Using the Experimental Modal Analysis

2006 ◽  
Vol 326-328 ◽  
pp. 1617-1620 ◽  
Author(s):  
Young Shin Lee ◽  
Hyun Soo Kim ◽  
C.H. Han
Keyword(s):  
Cylindrical Shell ◽  
Modal Analysis ◽  
Frequency Response Function ◽  
Circular Cylindrical Shell ◽  
Experimental Modal Analysis ◽  
Modal Testing ◽  
Frequency Range ◽  
Computer Screen ◽  
Vibrational Characteristics ◽  
Deformation Patterns

An experimental modal analysis is the process to identify structure's dynamic characteristics. For investigating vibrational characteristics of cylindrical shell with multiple supports, modal testing is performed using impact exciting method. The frequency response function(FRF) measurements are also made on the experimental model within the frequency range from 0 to 4kHz. Modal parameters are identified from resonant peaks in the FRF’s and animated deformation patterns associated with each of the resonances are shown on a computer screen. The experimental results are compared with analytical and FEA results.

Crack Detection in Composite Driving Shafts by Experimental Modal Analysis

1993 ◽  
Author(s):  
H. Irretier
Keyword(s):  
Modal Analysis ◽  
Crack Detection ◽  
Testing Machine ◽  
Circular Ring ◽  
The State ◽  
Experimental Modal Analysis ◽  
Modal Testing ◽  
Modal Damping ◽  
Bending Modes

Abstract A case study is presented in which a composite driving shaft of a motor-bike was loaded with different increasing numbers of load-cycles in a pulsating testing machine to reach different stages of damage. For each number of load-cycles an experimental modal analysis was performed by an iterative, global, multi-degree-of-freedom, frequency-domain modal testing technique and the eigenfrequencies and modal damping ratios were identified. From the results it is shown that the damping increases with the number of load-cycles i.e. the state of damage. However, it turned out that a more sensitive indicator for the state of damage is the splitting and shifting of the ‘double’ eigenfrequencies of the bending modes of the driving shaft with the ‘axisymmetric’ circular ring cross section. This fact is shown on the basis of several related experimental data.

scholarly journals Preliminary investigation on experimental modal analysis of high aspect ratio rectangular wing model

2018 ◽  
Vol 7 (4.13) ◽  
pp. 151
Author(s):  
N. A. Rosly ◽  
M. Y. Harmin ◽  
D. L. A. A. Majid
Keyword(s):  
Aspect Ratio ◽  
Modal Analysis ◽  
Mode Shape ◽  
High Aspect Ratio ◽  
Preliminary Investigation ◽  
Experimental Modal Analysis ◽  
Geometric Nonlinearities ◽  
Wing Model ◽  
Bending Modes ◽  
The Impact

Procedure of conducting an experimental modal analysis (EMA) of roving hammer test for high aspect ratio (HAR) wing containing geometric nonlinearities is presented along with consideration of various tip store sizes. Two sets of test setups of vertical and horizontal arrangements have been considered, which respectively demonstrates the undeformed and deformed cases. Modal properties in terms of natural frequency and mode shape were experimentally measured using the LMS Test.Lab package and the results were then compared between the undeformed and its corresponding deformed configuration. From the finding, it confirms that the chordwise and torsional modes of the undeformed configurations has respectively turned into chordwise-torsion and torsion-chordwise modes as they are in deformed configuration. Meanwhile, the impact related to bending modes is insignificant. Hence, this may result in inaccurate prediction if conventional aeroelastic solution is employed for HAR wing configuration.  

Sign in / Sign up

Export Citation Format

Share Document