Comparative study on damping test methods of concrete materials

Abstract

Damping is an important property of concrete, but there is no unified testing method at present. Four damping testing methods (the T-type method, cantilever beam method, simply supported beam method and suspension method), three analysis methods (half-power bandwidth method, INV damper method, time-domain method) and the influence of sampling frequencies on damping results were investigated. The results showed that the acceleration-time curve of the T-shaped method was the most uniform in the four testing methods. Its amplitude regularly weakened with time and tended to flatten slowly according to a specific trend. The T-shaped method presented a typical vibration attenuation and had high accuracy in measuring the damping value. While, the INV damper method can accurately calculate the damping ratio and loss factor without being affected by the frequency resolution and accurately calculate both the high frequency and low frequency simultaneously. The errors of the suspension method, the simply supported method, the cantilever beam method and the T-shaped method are 13.7%, 5.1%, 3.2% and 0.38%, respectively. Among the six sampling frequencies, a more accurate acceleration-time curve can be acquired when the sampling frequency is 256 Hz. Finally, two vibration models were built to verify the correctness of the experimental results.