Modal Analysis of a Drilling Machine for Blades of Wind Turbines

2011 ◽  
Vol 308-310 ◽  
pp. 1850-1854
Author(s):  
Yong Shu Jiao ◽  
Yong Liang Zhang ◽  
Mu Hui Fan
Keyword(s):  
Modal Analysis ◽  
Wind Turbines ◽  
Software Package ◽  
Natural Frequencies ◽  
Position Angle ◽  
Simplified Model ◽  
Drilling Machine ◽  
Structural Stress ◽  
Specific Working

In this paper, the authors conducted a modal analysis of a drilling machine for blades of wind turbines. A simplified model of the machine was established with a commercial FEM software package, Ansys. At a specific working position the first six order natural frequencies were calculated and the results obtained from two different contacting manners were compared. The influence of static structural stress induced by gravitational load on natural frequency was also evaluated. The variations of the natural frequencies of the machine with the position angle of the rotary box were subsequently obtained. This is helpful for the determination of range of the excitation frequencies.

Determination of Natural Frequencies of Spherical Cells

2008 ◽  
Author(s):  
Marjan Molavi ◽  
Ali Bonakdar ◽  
Ion Stiharu
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Living Cells ◽  
Health Condition ◽  
Comprehensive Analysis ◽  
Yeast Cells ◽  
Spherical Cells

In this paper, a finite element (FE) and scaled-up experimental modal analysis are employed to estimate the natural frequencies of the baker’s yeast cells. It is apparent the mechanical properties of the living cells and particularly the natural frequencies are highly related to the health condition of cells, and therefore a comprehensive analysis is carried out to determine the natural frequencies of individual cells.

Experimental and Numerical Modal Analysis of Gearbox Casing in a Polishing Machinery

2009 ◽  
Vol 69-70 ◽  
pp. 560-564
Author(s):  
Yang Yu Wang ◽  
Shi Ming Ji ◽  
Dong Hui Wen ◽  
Xian Zhang
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Test System ◽  
Structural Vibration ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Vibration Test ◽  
3D Fem ◽  
Fem Model

Vibrations in polishing machinery may affect the manual or automatic controls and reduce the efficiency of the operations to be carried out. In this article, an experimental and numerical analysis on the dynamic characteristic of a gearbox casing in polishing machinery have been carried out. The numerical investigation was achieved with NASTRAN based on a 3D FEM model and the experimental modal analysis for the determination of the natural frequencies and the associated eigenmodes of the gearbox casing with LMS structural vibration test system was performed. The fundamental modal parameters including the first 10-order natural frequencies, damping ratios and mode shapes were estimated and identified. Analytical and experimental results have been compared and discussed. Agreement between measurements and calculations is satisfactory and the results can be used as reliable reference for improving the dynamic behavior of the gearbox casing.

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.

Dynamic and Modal Analysis of a Snake like Robot

2020 ◽  
Vol 896 ◽  
pp. 203-210
Author(s):  
Leonard Marius Ciurezu-Gherghe ◽  
Nicolae Dumitru ◽  
Ionuţ Daniel Geonea ◽  
Cristian Copiluși
Keyword(s):  
Dynamic Analysis ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
Time Frequency

In this paper a modal and dynamic analysis of a snake like robot is performed. Modal analysis consist in determination of own vibration modes and natural frequencies. The proposed dynamic analysis was performed in order to determine the variation time/frequency laws for the cinematic and dynamics parameters.

scholarly journals Investigation of Metal-based Composites Vibration Properties Using Modal Analysis in Combination with Wavelet Transforms Under Imitation of Operational Loads

2020 ◽  
Vol 67 (2) ◽  
pp. 45-63
Author(s):  
Dmitrii S. Molchanov ◽  
Heinz Palkowski ◽  
Sergey Chernyakin ◽  
Panagiotis G. Karagiannidis
Keyword(s):  
Composite Materials ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Material Model ◽  
Elastic Behaviour ◽  
Metal Composite ◽  
Vibration Properties ◽  
Polymer Metal ◽  
Metal Composite Materials

AbstractThe present article is dedicated to the study of the vibration properties of metal-based composite materials and the application of the non-destructive testing method. The main modal parameters of the metal-based composites were investigated. For experimental determination of natural frequencies and modes of oscillations, the method of scanning laser Doppler vibrometry was used. For the numerical modal analysis, the finite element method was used. The material model was a layered composite with isotropic linearly elastic layers and metal layers. The task of identifying the material model was considered as the problem of minimising the discrepancy between the calculated natural frequencies and the experimental ones. The developed method can be recommended for the determination of parameters of material models for calculating the modal characteristics of polymer–metal sandwich sheets and metallic mono-materials composite products. Methodology for identifying models of elastic behaviour of polymer–metal composite materials, based on the results of the experimental modal analysis, is presented. Wavelet-based damage detection is also presented as an appropriate approach for the identification of integral conditions of the metal–polymer–metal composite materials. Results of wavelet transform convolutions are presented.

Investigation of Impact Profile and Isolation Effect in Automated Impact Device Design and Control for Operational Modal Analysis

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Z. C. Ong ◽  
C. C. Lee
Keyword(s):  
Modal Analysis ◽  
Isolation Effect ◽  
Time Averaging ◽  
Impact Device ◽  
Lack Of Information ◽  
Analysis Technique ◽  
And Control ◽  
Phase Angles ◽  
Synchronous Time

A novel modal analysis technique called impact-synchronous modal analysis (ISMA) was introduced in previous research. With the utilization of impact-synchronous time averaging (ISTA), this modal analysis can be performed in presence of ambient forces whereas the conventional analysis method requires machines to be totally shut down. However, lack of information of phase angles with respect to impact in ISMA has caused it to be labor-intensive and time-consuming. An automated impact device (AID) is introduced in this study in the effort to replace the manually operated impact hammer and prepare it to be used in the current practice of ISMA on the purpose of enhancing its effectiveness and practicability. Impact profile and isolation effect are noted to be the contributing parameters in this study. This paper devoted on calibrating and controlling of the AID which gives the desired impact profiles as compared to the manual impact hammer. The AID is found effective in the determination of dynamic characteristics when the device is isolated from the boundary condition of the test structure.

scholarly journals Determination of stress-strain state of the wooden church log walls with software package

2016 ◽  
Vol 86 ◽  
pp. 02019 ◽  
Author(s):  
Anastasia Chulkova ◽  
Sergey Lukichev ◽  
Marina Romanovich
Keyword(s):  
Software Package ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State
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