Estimation of bending wave intensity in beams using the frequency response technique

Jukka Linjama, Tapio Lahti

Research output: Contribution to journalArticleScientificpeer-review

43 Citations (Scopus)


The frequency response approach is applied to the measurement of bending wave intensity, with two or four accelerometers being used. Based on the known structural intensity equations, a comprehensive set of frequency domain expressions is derived for power measurements in a beam. A practical procedure is developed for the general four-transducer method, which allows a usual dual channel FFT analyzer to be employed in multi-channel measurements. The procedure uses the sequential frequency response technique, and is applicable if the situation remains stationary during the data acquisition. In addition, expressions are derived for the determination of the force- and moment-related bending wave power components separately. In a laboratory experiment, the power carried by bending waves was measured in a simple beam, and the methods developed were tested and compared. The frequency response approach was shown to work well in detecting the total power. The estimation of the two bending wave power components, both in the near and the far field, was also demonstrated.
Original languageEnglish
Pages (from-to)21-36
JournalJournal of Sound and Vibration
Issue number1
Publication statusPublished - 1992
MoE publication typeA1 Journal article-refereed


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