scholarly journals Vibrational Energy Flow Model for a High Damping Beam with Constant Axial Force

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Xiaoyan Teng ◽  
Nan Liu ◽  
Jiang Xudong
Keyword(s):  
Energy Density ◽  
Axial Force ◽  
Energy Flow ◽  
Loss Factor ◽  
Vibrational Energy ◽  
Flow Analysis ◽  
Structural Damping ◽  
Energy Density Distribution ◽  
Damping Loss Factor ◽  
The Relationship

The energy flow analysis (EFA) method is developed to predict the energy density of a high damping beam with constant axial force in the high-frequency range. The energy density and intensity of the beam are associated with high structural damping loss factor and axial force and introduced to derive the energy transmission equation. For high damping situation, the energy loss equation is derived by considering the relationship between potential energy and total energy. Then, the energy density governing equation is obtained. Finally, the feasibility of the EFA approach is validated by comparing the EFA results with the modal solutions for various frequencies and structural damping loss factors. The effects of structural damping loss factor and axial force on the energy density distribution are also discussed in detail.

scholarly journals Validity Investigation of Random Energy Flow Analysis for Beam Structures

2011 ◽  
Vol 18 (1-2) ◽  
pp. 269-280 ◽  
Author(s):  
Jin You ◽  
Hong-Guang Li ◽  
Guang Meng
Keyword(s):  
Energy Density ◽  
Energy Flow ◽  
Flow Analysis ◽  
Approximate Solutions ◽  
Wide Frequency Range ◽  
Exact Methods ◽  
Beam Structures ◽  
Energy Density Distribution ◽  
Energy Flow Analysis ◽  
Random Energy

The validity of the application of energy flow analysis for beam structures under random excitations is investigated in this paper. The approximate solutions of energy density and intensity in a beam subject to random loadings are obtained by solving the governing equation of random energy flow analysis using Fourier transform technique. The formulations of the exact energy density distribution and intensity in the beam are derived using the classical modal analysis method. For a simply supported beam subject to distributed or concentrated random excitations, the validity of random energy flow analysis is investigated through comparisons between solutions obtained from the approximate and exact methods for energy response as well as intensity. The results indicate that, the mode count of the analysis frequency band, which means the number of modes involved in the band, is the key factor affecting the prediction accuracy of random energy flow analysis, and that if the mode count of the band is sufficiently large, random energy flow analysis can provide rather accurate estimates for both energy density and intensity in a wide frequency range.

scholarly journals Analytical model of high-frequency energy flow response for a beam with free layer damping

2020 ◽  
Vol 12 (12) ◽  
pp. 168781402098459
Author(s):  
Xiaoyan Teng ◽  
Nan Liu ◽  
Xudong Jiang
Keyword(s):  
Energy Density ◽  
Exact Solutions ◽  
Governing Equation ◽  
High Frequency ◽  
Energy Flow ◽  
Vibrational Energy ◽  
Flow Analysis ◽  
Free Layer ◽  
Transfer Coefficients ◽  
Equivalent Complex

Energy flow analysis (EFA) is developed to predict the vibrational energy density of beam structures with both full free layer damping (FFLD) and partial free layer damping (PFLD) treatments in the high frequency range. Both equivalent flexural stiffness and structural damping loss factor of a beam with free layer damping are obtained using the equivalent complex stiffness method. Then the energy density governing equation considering high damping effect is derived for a beam with FFLD treatment. Following obtainment of the energy transfer coefficients at both ends of free damping layer, the energy density within a beam with PFLD treatment is evaluated by solving the presented energy governing equation. To verify the proposed formulation, numerical simulations are performed for the pinned-pinned beams with FFLD and PFLD treatments. The EFA results are compared with the exact solutions from wave analysis at various frequencies, and good correlations are observed between the developed EFA results and the exact solutions.

scholarly journals Development of energy flow models to predict sound fields for sound absorbing structures in medium-to-high frequency ranges

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110046
Author(s):  
Tae-Gyoung Kim ◽  
Suk-Yoon Hong ◽  
Jee-Hun Song ◽  
Hyun-Wung Kwon
Keyword(s):  
Energy Density ◽  
Governing Equation ◽  
High Frequency ◽  
Energy Flow ◽  
Flow Analysis ◽  
Acoustic Energy ◽  
Acoustic Properties ◽  
Experimental Result ◽  
Sound Fields ◽  
Absorbing Materials

Energy flow analysis (EFA) model for the treatment of sound absorbing structures is developed to predict sound fields of engineering systems in medium-to-high frequency ranges. Thus far, EFA for acoustic models has been developed only for low damping media, such as air and water. A new energy flow governing equation is derived in this study by identifying a relationship between energy density gradient and intensity and acoustic energy dissipation for sound absorbing materials. With the developed EFA model, dispersive wave, and loss factors are identified using complex acoustic properties, and they are investigated to make ensure that they reflect the properties of sound absorbing materials. By solving the governing equation, acoustic energy density, and intensity distributions in sound absorbing materials are obtained, and noise analyses are performed for sound absorbing structures. They are compared with those obtained via a conventional method and experimental result for the verification, in which we confirmed that both results agreed well. Furthermore, various sound absorbing structures are analyzed using the developed EFA model to predict sound fields in medium-to-high frequency ranges. It is demonstrated that the developed EFA model is useful for medium-to-high frequency ranges.

scholarly journals Vibrational Energy Flow Analysis of Corrected Flexural Waves in Timoshenko Beam – Part II: Application to Coupled Timoshenko Beams

2006 ◽  
Vol 13 (3) ◽  
pp. 167-196 ◽  
Author(s):  
Young-Ho Park ◽  
Suk-Yoon Hong
Keyword(s):  
Timoshenko Beam ◽  
Energy Flow ◽  
Vibrational Energy ◽  
Flow Analysis ◽  
Companion Paper ◽  
Wave Transmission ◽  
Classical Solutions ◽  
Flexural Waves ◽  
Beam Structures ◽  
Energy Flow Analysis

This paper presents the methodology for the energy flow analysis of coupled Timoshenko beam structures and various numerical applications to verify the developed methodology. To extend the application of the energy flow model for corrected flexural waves in the Timoshenko beam, which is developed in the other companion paper, to coupled structures, the wave transmission analyses of general coupled Timoshenko beam systems are performed. First, power transmission and reflection coefficients for all kinds of propagating waves in the general, coupled Timoshenko beam structures are derived by the wave transmission approach. In numerical applications, the energy flow solutions using the derived coefficients agree well with the classical solutions for various exciting frequencies, damping loss factors, and coupled Timoshenko beam structures. Additionally, the numerical results for the Timoshenko beam are compared with those for the Euler-Bernoulli beam.

scholarly journals Energy Flow Analysis of One-Dimensional Structures with Random Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Kun Wang ◽  
Yu Fu ◽  
Jiafu Liu ◽  
Qi Zhang
Keyword(s):  
Energy Density ◽  
Numerical Simulations ◽  
Energy Flow ◽  
Vibration Analysis ◽  
Flow Analysis ◽  
New Approach ◽  
One Dimensional ◽  
Random Energy ◽  
Uncertainty Parameters ◽  
Random Responses

In this work, the energy density responses of one-dimensional structures with random properties are investigated analytically. Based on Green kernels, analytical representations of energy density for vibrating rods and beams are proposed using the superposition of energy waves. Considering random properties in rods and beams, formulations of energy density responses are obtained. Then, the mathematical expectations and variances are derived. And response intervals for random responses are developed. Finally, numerical simulations are performed to validate the proposed formulations, and characteristics of the random energy density responses of rods and beams are analysed. The main contribution of this work is that a new approach to energy density responses is proposed which facilitates the vibration analysis of structures with uncertainty parameters.

Electric and Damping Properties of PU Based IPNs-BaTiO3 Nanocomposites

2007 ◽  
Vol 336-338 ◽  
pp. 118-120
Author(s):  
Dong Yan Tang ◽  
Zheng Jin ◽  
Liang Sheng Qiang
Keyword(s):  
Dielectric Properties ◽  
Loss Factor ◽  
Synergistic Effects ◽  
Electric Properties ◽  
Damping Properties ◽  
Damping Property ◽  
Frictional Damping ◽  
Damping Loss Factor ◽  
The Relationship

(PU/UP IPNs)-BaTiO3 nanocomposites with different amounts of BaTiO3 nanopowder are prepared and polarized. The ferroelectric and dielectric properties are detected and the relationship between electric properties and damping properties are discussed in detail. Results indicate that the synergistic effects can be created successfully by elastic damping of polymer, frictional damping of BaTiO3, and piezoelectric damping of nanocomposites after poling. The nanocomposites increase the damping property evidently and sustain mostly ferroelectric and dielectric characters of inorganic phase. The introduction of BaTiO3 into IPNs decreases the resistivity, and this has advantages to enlarge the damping loss factor (tanδ).

scholarly journals Development of Non-Conservative Joints in Beam Networks for Vibration Energy Flow Analysis

2007 ◽  
Vol 14 (1) ◽  
pp. 15-28 ◽  
Author(s):  
Jee-Hun Song ◽  
Suk-Yoon Hong
Keyword(s):  
Energy Flow ◽  
Degrees Of Freedom ◽  
Vibrational Energy ◽  
Flow Analysis ◽  
Energy Flow Analysis ◽  
Internal Loss ◽  
Joint Properties ◽  
Flow Through ◽  
Coupled Structures ◽  
Coupling Angle

Our work aims to find a general solution for the vibrational energy flow through a plane network of beams on the basis of an energy flow analysis. A joint between two semi-infinite beams are modeled by three sets of springs and dashpots. Thus, the results can incorporate the case of complaint and non-conservative in all the three degrees of freedom. In the cases of finite coupled structures connected at a certain angle, the derived non-conservative joints and developed wave energy equation were applied. The joint properties, the frequency, the coupling angle, and the internal loss factor were changed to evaluate the proposed methods for predicting medium-to-high frequency vibrational energy and intensity distributions.

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