國立虎尾科技大學 |

Application of complex modal decomposition methods to dispersive media.

紀錄類型:	書目-語言資料,手稿 : Monograph/item
正題名/作者:	Application of complex modal decomposition methods to dispersive media./
作者:	Caldwell, Rickey Alfred, Jr.
面頁冊數:	1 online resource (109 pages)
附註:	Source: Dissertation Abstracts International, Volume: 78-05(E), Section: B.
Contained By:	Dissertation Abstracts International78-05B(E).
標題:	Mechanical engineering. -
電子資源:	click for full text (PQDT)
ISBN:	9781369305265

Application of complex modal decomposition methods to dispersive media.
Caldwell, Rickey Alfred, Jr.

Application of complex modal decomposition methods to dispersive media. - 1 online resource (109 pages)

Source: Dissertation Abstracts International, Volume: 78-05(E), Section: B.

Thesis (Ph.D.)

Includes bibliographical references

Complex orthogonal decomposition (COD) is applied to an experimental beam to extract the dispersive wave properties using response measurements. The beam is made of steel and is rectangular with a constant cross section. One end of the beam is free and is hung by a soft elastic cord. An impulse is applied to the free end. The other end is buried in sand to absorb the wave as it travels from the impact site on the free-end; this effectively prevents reflections of the wave off the buried end and emulates a semi-infinite beam. COD is applied to the complex analytic displacement ensemble to obtain complex modal vectors and associated complex modal coordinates. The spatial whirl rates of nearly harmonic modal vectors are used to extract the modal wave numbers, and the temporal whirl rates of the modal coordinates are used to estimate the modal frequencies. The relationship between the frequencies and wave numbers are used to describe the dispersion relationships, which are compared favorably to those of the theoretical infinite Euler-Bernoulli beam. Further efforts are applied, and a new methodology is developed.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781369305265Subjects--Topical Terms:

557493
Mechanical engineering.
Index Terms--Genre/Form:

554714
Electronic books.

Application of complex modal decomposition methods to dispersive media.
LDR:04355ntm a2200373Ki 4500 001 909535
005 20180426100013.5
006 m o u
007 cr mn||||a|a||
008 190606s2016 xx obm 000 0 eng d
020 $a 9781369305265
035 $a (MiAaPQ)AAI10182083
035 $a (MiAaPQ)grad.msu:14913
035 $a AAI10182083
040 $a MiAaPQ $b eng $c MiAaPQ
099 $a TUL $f hyy $c available through World Wide Web
100 1 $a Caldwell, Rickey Alfred, Jr. $3 1180361
245 1 0 $a Application of complex modal decomposition methods to dispersive media.
264 0 $c 2016
300 $a 1 online resource (109 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertation Abstracts International, Volume: 78-05(E), Section: B.
500 $a Adviser: Brian F. Feeny.
502 $a Thesis (Ph.D.) $c Michigan State University $d 2016.
504 $a Includes bibliographical references
520 $a Complex orthogonal decomposition (COD) is applied to an experimental beam to extract the dispersive wave properties using response measurements. The beam is made of steel and is rectangular with a constant cross section. One end of the beam is free and is hung by a soft elastic cord. An impulse is applied to the free end. The other end is buried in sand to absorb the wave as it travels from the impact site on the free-end; this effectively prevents reflections of the wave off the buried end and emulates a semi-infinite beam. COD is applied to the complex analytic displacement ensemble to obtain complex modal vectors and associated complex modal coordinates. The spatial whirl rates of nearly harmonic modal vectors are used to extract the modal wave numbers, and the temporal whirl rates of the modal coordinates are used to estimate the modal frequencies. The relationship between the frequencies and wave numbers are used to describe the dispersion relationships, which are compared favorably to those of the theoretical infinite Euler-Bernoulli beam. Further efforts are applied, and a new methodology is developed.
520 $a A novel method called smooth complex orthogonal decomposition (SCOD) is applied to a simulated semi-infinite beam and the above instrumented experimental beam. These measurements are converted into complex analytic displacements and velocities ensembles, which are used to compute two correlation matrices. These correlation matrices form a complex generalized eigenvalue problem whose eigenvalues and eigenvectors lead to the extractions of the frequencies and wavenumbers of the constituent waves of the traveling pulse. SCOD directly extracts the frequencies of the traveling waves from the eigenvalues. SCOD can extract the geometric relationship, phase velocity, and group velocity and agrees with analytical predictions. Applications of both methods are applied to a simulated infinite mass chain.
520 $a The dispersion relationship of a discrete chain of masses is extracted from numerically simulated data by applying complex modal decomposition. When an impulse excitation is applied to one end of a semi-infinite mass-spring chain, a wave is generated and propagates down the chain. This wave consists of various modes. The time record for the generated data is limited such that the wave reflection does not return to the sensed masses. For example, a 250-mass chain is simulated, and we consider (or sense) the time record of the first 100 masses. The data collected from the numerical simulation consists of the displacements of each mass at each time step. This data is then used to extract complex modes using COD and SCOD. The extracted complex modes accommodate modal traveling waves. We then compute the frequencies and wave numbers from modal coordinates and mode shapes, respectively. The amplitudes and frequencies of the modes are also estimated using Rayleigh quotients. The COD extracted dispersion relationship matches the analytical prediction of the dispersion curve for the linear mass chain.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Mechanical engineering. $3 557493
650 4 $a Acoustics. $3 670692
655 7 $a Electronic books. $2 local $3 554714
690 $a 0548
690 $a 0986
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a Michigan State University. $b Mechanical Engineering. $3 845689
773 0 $t Dissertation Abstracts International $g 78-05B(E).
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10182083 $z click for full text (PQDT)