Damping identification from non-linear random responses using a multi-triggering random decrement technique
✍ Scribed by Samir R. Ibrahim; K.R. Wentz; J. Lee
- Publisher
- Elsevier Science
- Year
- 1987
- Tongue
- English
- Weight
- 747 KB
- Volume
- 1
- Category
- Article
- ISSN
- 0888-3270
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✦ Synopsis
The concept of multi-triggering random decrement technique is introduced. Like the single triggering technique, it reduces multi-mode multi-measurement stationary random responses to free decay responses but has the advantage of increasing the apparent number of the resulting free decay time response functions. The maximum number of these free decay responses is equal to the square of the number of random measurements. These free decay responses are then used in a linear time domain modal identification algorithm to extract frequencies, damping factors and mode shapes of a structure under test. The quasi-linear modal approach is used to deal with non-linearities by repeating the linear identification process at different levels of inputs/responses. The procedure is applied to rectangular panels subjected to acoustic random input ranging from 130 to 157 dB. The changes in frequencies and damping factors with input level are reported. This application is part of a sonic fatigue research program.