We address the problem of structural model identification during normal operating conditions and thus with uncontrolled, unmeasured, and nonstationary excitation. We advocate the use of output-only and covariance-driven subspace-based stochastic identification methods. We explain how to handle nonsimultaneously measured data from multiple sensor setups, and how robustness with respect to nonstationary excitation can be achieved. Experimental results obtained for three real application examples are shown.

Issue Section:
Technical Papers
Keywords:
identification, state-space methods, covariance matrices, aerospace testing, Subspace-Based Stochastic Identification Methods, In-Operation Output-Only Structural Identification, Nonstationary Excitation, Multiple Sensor Setups
Topics:
Algorithms, Excitation, Sensors, Testing, Damping, Flight, Robustness
1.
Zimmerman, H., and Destuynder, R., 1982, “Flight Flutter Testing with Emphasis on the Tip Vane Method,” Proceedings, AGARD Conf. 339 on Ground Flight Testing & Correlation.
2.
Schippers, P., and Persoon, A. J., 1995, “Flight Flutter Testing of a Turbo Prop Aircraft by using External Excitation Devices,” Proceedings, AGARD Conf. 566 on Advanced Aeroservoelastic Testing and Data Analysis, Rotterdam (NL), pp. 3.1–3.11.
3.
De Vis, D., Gielen, L., Verhoeven, J.,;Nordmann, R., and Neumer, T., 1992, “Indirect identification of fluid structure interaction forces in boilerfeed pumps,” Proceedings, 10th International Modal Analysis Conference, San Diego (CA), pp. 47–53.
4.
Ewins, D. J., 1984, Modal Testing: Theory and Practice, Research Studies Press, Letchworth, Hertfordshire, UK.
5.
Juang, J. N., 1994, Applied System Identification, Prentice Hall, Englewood Cliffs, NJ.
6.
De Roeck, G., Peeters, B., and Ren, W.-X., 2000, “Benchmark study on system identification through ambient vibration measurements,” Proceedings, 18th International Modal Analysis Conference, San Antonio, TX, pp. 1106–1112.
7.
Viberg
,
M.
,
1995
, “
Subspace-based methods for the identification of linear time-invariant systems
,”
Automatica
,
31
, No.
12
, pp.
1835
–
1853
.
8.
Van Overschee, P., and De Moor, B., 1996, Subspace Identification for Linear Systems: Theory-Implementation-Applications, Kluwer Academic Publishers.
9.
Van Overschee
,
P.
, and
De Moor
,
B.
,
1994
, “
N4SID: Subspace algorithms for the identification of combined deterministic-stochastic systems
,”
Automatica
,
30
, No.
2
, pp.
75
–
93
.
10.
Viberg
,
M.
,
Wahlberg
,
B.
, and
Ottersten
,
B.
,
1997
, “
Analysis of state space system identification methods based on instrumental variables and subspace fitting
,”
Automatica
,
33
, No.
9
, pp.
1603
–
1616
.
11.
Peeters
,
B.
, and
De Roeck
,
G.
,
1999
, “
Reference-based stochastic subspace identification for output-only modal analysis
,”
Mech. Syst. Signal Process.
,
13
, No.
6
, pp.
855
–
878
.
12.
Prevosto
,
M.
,
Olagnon
,
M.
,
Benveniste
,
A.
,
Basseville
,
M.
, and
LeVey
,
G.
,
1991
, “
State-space formulation, a solution to modal parameter estimation
,”
J. Sound Vib.
,
148
, pp.
329
–
342
.
13.
Stoı¨ca, P., and Moses, R. L., 1997, Introduction to Spectral Analysis, Prentice Hall.
14.
Akaı¨ke
,
H.
,
1974
, “
Stochastic theory of minimal realization
,”
IEEE Trans. Autom. Control
,
AC-19
, pp.
667
–
674
.
15.
Benveniste
,
A.
, and
Fuchs
,
J.-J.
,
1985
, “
Single sample modal identification of a nonstationary stochastic process
,”
IEEE Trans. Autom. Control
,
AC-30
, pp.
66
–
74
.
16.
Akaı¨ke
,
H.
,
1973
, “
Markovian representation of stochastic processes by canonical variables
,”
SIAM J. Control
,
13
, pp.
162
–
173
.
17.
Basseville
,
M.
,
Abdelghani
,
M.
, and
Benveniste
,
A.
,
2000
, “
Subspace-based fault detection algorithms for vibration monitoring
,”
Automatica
,
36
, pp.
101
–
109
.
18.
Arun, K. S., and Kung, S. Y., 1986, “Generalized principal components analysis and its application in approximate stochastic realization,” Modeling and Application of Stochastic Processes, U. B. Desai, ed., Kluwer Academic Publishers, pp. 75–103.
19.
Mevel, L., Benveniste, A., Basseville, M., and Goursat, M., 2000, “Blind subspace-based eigenstructure identification under nonstationary excitation using moving sensors,” IRISA Research Report no 1354, http://www.irisa.fr/bibli/publi/pi/2000/1354/1354.html.
20.
Abdelghani, M., Goursat, M., Biolchini, T., Hermans, L., and Van der Auweraer, H., 1999, “Performance of output-only identification algorithms for modal analysis of aircraft structures,” Proceedings, 17th International Modal Analysis Conference, Kissimmee, FL, pp. 224–230.
21.
Hermans
,
L.
, and
Van der Auweraer
,
H.
,
1999
, “
Modal testing and analysis of structures under operational conditions: industrial applications
,”
Mech. Syst. Signal Process.
,
13
, No.
2
, pp.
193
–
216
.
22.
Basseville
,
M.
,
Benveniste
,
A.
,
Gach-Devauchelle
,
B.
,
Goursat
,
M.
,
Bonnecase
,
D.
,
Dorey
,
P.
,
Prevosto
,
M.
, and
Olagnon
,
M.
,
1993
, “
Damage monitoring in vibration mechanics: issues in diagnostics and predictive maintenance
,”
Mech. Syst. Signal Process.
,
7
, No.
5
, pp.
401
–
423
.
23.
Goursat, M., Basseville, M., Benveniste, A., and Mevel, L., 2000, “A Scilab toolbox for output only modal analysis and diagnosis,” Proceedings, 18th International Modal Analysis Conference, San Antonio (TX). ftp://ftp.inria.fr/INRIA/Projects/Meta2/Scilab/contrib/MODAL/.
24.
Allemang
,
R. J.
, and
Brown
,
D. L.
,
1998
, “
A unified matrix polynomial approach to modal identification
,”
J. Sound Vib.
,
211
, pp.
301
–
322
.
25.
Van der Auweraer, H., Leurs, W., Mas, P., and Hermans, L., 2000, “Modal parameter estimation from inconsistent data sets,” Proceedings, 18th International Modal Analysis Conference, San Antonio, TX, pp. 763–771.
26.
Abdelghani
,
M.
,
Goursat
,
M.
, and
Biolchini
,
T.
,
1999
, “
On-line monitoring of aircraft structures under unknown excitation
,”
Mech. Syst. Signal Process.
,
13
, No.
6
, pp.
839
–
853
.
27.
Ottersten
,
B.
,
Viberg
,
M.
, and
Kailath
,
T.
,
1992
, “
Analysis of subspace fitting and ML techniques for parameter estimation
,”
IEEE Trans. Signal Process.
,
40
, pp.
590
–
599
.
28.
Bauer
,
D.
,
Deistler
,
M.
, and
Scherrer
,
W.
,
1999
, “
Consistency and asymptotic normality of some subspace algorithms for systems without observed inputs
,”
Automatica
,
35
, pp.
1243
–
1254
.
29.
Benveniste, A., Basseville, M., and Mevel, L., 2000, “Convergence rates for eigenstructure identification using subspace methods,” Proceedings, 39th IEEE Conference on Decision and Control, Sydney, Australia.
30.
Uhl, T., Bochniak, W., Lisowski, W., Hermans, L., Van der Auweraer, H., and Malecki, J., 1999, “FE-model correlation of a helicopter using ground test results,” Proceedings, 17th International Modal Analysis Conference, Kissimmee, FL, pp. 940–946.
31.
Lisowski, W., Uhl, T., Malecki, J., Hermans, L., and Van der Auweraer, H., 2000, “Investigation of structural dynamics properties of helicopter airframe,” Proceedings, ISMA 25, Leuven (B), pp. 627–634.
32.
Peeters, B., and De Roeck, G., 2000, “One year monitoring of the Z24-bridge: environmental effects versus damage events,” Proceedings, 18th International Modal Analysis Conference, San Antonio, TX, pp. 1570–1576.
33.
Mevel
,
L.
,
Hermans
,
L.
, and
Van der Auweraer
,
H.
,
1999
, “
Application of a subspace-based fault detection method to industrial structures
,”
Mech. Syst. Signal Process.
,
13
, No.
6
, pp.
823
–
838
.
34.
Basseville
,
M.
,
1998
, “
On-board component fault detection and isolation using the statistical local approach
,”
Automatica
,
34
, No.
11
, pp.
1391
–
1416
.
35.
Basseville, M., and Nikiforov, I. V., 1993, Detection of Abrupt Changes-Theory and Applications, Prentice Hall, Englewood Cliffs, N.J. http://www.irisa.fr/sigma2/kniga.
36.
Gach-Devauchelle, B., 1991, “Diagnostic Me´canique des Fatigues sur les Structures Soumises a` des Vibrations en Ambiance de Travail,” Thesis, Paris IX Dauphine University (in French).
Copyright © 2001
 by ASME
You do not currently have access to this content.