Damping identification of structure using free vibration data

Bui Thanh Tam

Damping identification of structure using free vibration data - Bangkok : Asian Institute of Technology, 1991 - 55 p. - Thesis ; no. ST-91-01 . - Asian Institute of Technology. Thesis ; no. ST-91-01 .

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1991

Quantification of damping is by far the most vexing problem in dynamics of structures, because damping does not refer to a unique physical phenomenon. The ability to estimate damping ratios accurately plays an important role in the design of dynamically sensitive structures. A modern method of system identification, the Ibrahim Time Domain method, is applied to estimate the modal characters of structure. The effect of the white noise on the accuracy of identifying natural frequency and damping ratio is investigate through numerical examples : Single degree of freedom system, three degree of freedom system, and structure with a tuned mass damper (TMD). The results confirm that the accuracy of the solution depends on the number and characteristics of data series, on the number of data points, on the sampling period, on the closeness of natural frequencies, and on the magnitude of damping. The study also shows the advantages of the method over the logarithmic decrement method.


Structural dynamics--Statistical methods
Damping (Mechanics)
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