Application of a three degree of freedom laser vibrometer for experimental modal analysis

John A. Cafeo, Martin Wesley Trethewey, Joseph R. Rieker, Henry Joseph Sommer, III

Research output: Contribution to journalConference articlepeer-review

3 Scopus citations


This paper discusses a novel noncontacting measurement approach, capable of simultaneously sensing one dynamic translation and two dynamic angular rotations, and its application for experimental modal analysis. The transducer system is based on the positional measurement of two laser beams reflected from a planar target. Using the geometric orientation between the incident light beams and the corresponding reflections onto two position sensing photodetectors, the translation, pitch angle and roll angle of a planar target can be determined. The paper briefly discusses operation of the transducer and its performance. The transducer is applied to the modal analysis of two structures (a cantilever beam and a printed circuit board) to demonstrate the transducer's characterisitics, utility and unique capability for simultaneous noncontacting measurement of two dynamic angular rotations. The work investigates the use of the structural rotational data to refine spatial description of mode shapes.

Original languageEnglish (US)
Pages (from-to)1161-1167
Number of pages7
JournalProceedings of the International Modal Analysis Conference - IMAC
StatePublished - Jan 1 1991
EventProceedings of the 9th International Modal Analysis Conference Part 2 (of 2) - Florence, Italy
Duration: Apr 15 1991Apr 18 1991

All Science Journal Classification (ASJC) codes

  • Engineering(all)


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