| Autor: |
Gidrão, Gustavo de Miranda Saleme, Krahl, Pablo Augusto, Carrazedo, Ricardo |
| Předmět: |
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| Zdroj: |
Journal of Materials in Civil Engineering; Dec2020, Vol. 32 Issue 12, p1-16, 16p |
| Abstrakt: |
This paper reports the characterization of internal damping ratio (ξ) and Q factor of ultrahigh-performance fiber-reinforced concrete (UHPFRC) using acoustic tests for undamaged and damaged samples excited by an impact. Ratio ξ is a nondimensional parameter that measures the material capacity to dissipate vibration, and the Q factor is physically interpreted as inverse attenuation, measuring the undamped characteristics of an oscillator. A servohydraulic testing machine was used for straining the samples cyclically, and at the end of each cycle the acoustic tests were made to measure ξ and Q. Furthermore, scanning electron microscopy (SEM) was performed in samples extracted from the damaged specimens. From results, undamaged samples presented average ξ around 0.35% with maximum and minimum values of 0.50% and 0.15%, respectively. The analysis of damaged samples showed that the internal damping gave a small variation in the first two load cycles and achieved 0.8% after the peak stress. Low values of ξ found in the present study suggest that UHPFRC structures are more susceptible to excessive vibrations than normal-strength concrete structures. Moreover, SEM images showed damage mechanisms that are the probable reasons for the increase of ξ after severe loading. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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