Displacement Based Approach for a Robust Operational Modal Analysis
Robust estimation of the dynamic modal parameters of structures during shaking table experiments is done by means of efficient time domain data-driven Crystal Clear Stochastic Subspace Identification (CC-SSI) of vibration data recorded by a new, innovative, high resolution 3-D optical movement detection and analysis tool tracking the dynamic displacement of several selected points of the structures during the dynamic tests of natural (earthquake) and artificial (mechanical) induced vibrations. The measure of the displacements is a crucial task for the numerical and experimental studies in structural dynamics, especially within the displacement based approach in seismic design and calculations. The innovative monitoring technique measures 3 axial absolute displacements with easy and fast test setup, high accuracy and the possibility to link the 3D-motion time histories of the tracked markers with CAD drawings of the structure and validate the FE models in real time experimental data assimilation.
KeywordsMode Shape Modal Parameter Frequency Response Function Stabilization Diagram Torsion Mode
Unable to display preview. Download preview PDF.
- 1.Doughty, T. A. and Higgins, N. S., “Effect of Nonlinear Parametric Model Accuracy in Crack Prediction and Detection”, SEM Annual Conference & Exposition on Experimental and Applied Mechanics, Indianapolis, 2010.Google Scholar
- 6.Gudmundson, P., “Changes in Modal Parameters Resulting from Small Cracks,” Proceedings of the International Modal Analysis Conference and Exhibit 2, 1984, pp. 690-697.Google Scholar
- 12.Sih, G.C., Tzou, D.Y., “Mechanics of Nonlinear Crack Growth: Effects of Specimen Size and Loading Step,” Martinus Nijhoff Publications, 1984, pp. 155-169.Google Scholar
- 13.Bovsunovsky, A. and Bovsunovsky, O., “Crack Detection in Beams by Means of the Driving Force Parameters Variation at Non-Linear Resonance Vibrations”, Key Engineering Materials, v 347, Damage Assessment of Structures VII, 2007, pp. 413-420.Google Scholar
- 14.Andreaus, U., Casini, P., Vestroni, F., “Nonlinear Features In The Dynamic Response of a Cracked Beam Under Harmonic Forcing,” Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference - DETC2005, v 6 C, 5th International Conference on Multibody Systems, Nonlinear Dynamics, and Control, 2005, pp. 2083-2089.Google Scholar
- 15.Wowk, V., Machinery Vibration Measurement and Analysis, McGraw Hill, Inc. New York, 1991.Google Scholar
- 16.Crespo da Silva, M. R. M. and Glynn, C. C., “Nonlinear Flexural-Flexural-Torsional Dynamics of Inextensional Beams, II. Forced Motions,” International Journal of Solids and Structures 6, 1978, pp. 449-461.Google Scholar
- 18.Doughty, Timothy A., System Identification of Modes in Nonlinear Structures. PhD Thesis, Ray W. Herrick Laboratories, School of Mechanical Engineering, Purdue University, 2002.Google Scholar
- 19.Doughty, T. A. and Leineweber, M. J., “Investigating Nonlinear Models for Health Monitoring in Vibrating Structures”, ASME International Mechanical Engineering Congress and Exposition, November 2009.Google Scholar