Investigations on a novel technique for experimental structural dynamics: Theoretical analysis of impact testing using CSLDV

R. Ribichini*, D. Di Maio, A. B. Stanbridge, D. J. Ewins

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

1 Citation (Scopus)

Abstract

In the past decade, Continuous Scanning Laser Doppler Velocimetry (CSLDV) has been successfully used in experimental modal analysis and vibration tests. Essentially, this technique consists in the use of a Laser Scanning Velocimeter (LDV) moving continuously across a vibrating surface rather than stepping in a point-by- point fashion. If the structure is undergoing harmonic vibration, its Operating Deflection Shape (ODS) can be recovered in a very short time and without the limitations in spatial resolution typical of discrete point measurements. Recently, this technique has been extended to transient excitation -i.e. the object is swept by the laser transducer during a period of transient free response caused by an impact. The combination of a broadband excitation with a full-field measurement results in a highly complex signal, modulated both by the mode shapes of the structure and by the exponential decays due to damping effects. Thus, the signal contains in its spectrum a mixture of temporal information (the eigenvalues of the structure) and spatial information (the eigenvectors), all in a single time history. This paper presents a mathematical model of this new concept, first applied to a simple one-dimensional scan and then to a rectangular 2-D area scan. The numerically-simulated signals of the 1-D case are compared with actual measurements, both in time and frequency domains. Finally, an analysis of the measurement parameters involved in this method is provided.

Original languageEnglish
Title of host publicationEighth International Conference on Vibration Measurements by Laser Techniques
Subtitle of host publicationAdvances and Applications
DOIs
Publication statusPublished - 2008
Externally publishedYes
Event8th International Conference on Vibration Measurements by Laser Techniques: Advances and Applications 2008 - Ancona, Italy
Duration: 18 Jun 200820 Jun 2008
Conference number: 8

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume7098
ISSN (Print)0277-786X

Conference

Conference8th International Conference on Vibration Measurements by Laser Techniques: Advances and Applications 2008
CountryItaly
CityAncona
Period18/06/0820/06/08

Keywords

  • Continuous Scanning
  • CSLDV
  • Impact Testing
  • LDV

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