Multifractal Characteristics of Acoustic Emission Signals of Concrete Under Axial Tension With Different Steel Fiber Contents

In order to study the evolution law of axial tensile damage of concrete with varying steel fiber content and to obtain precursor information for axial tensile damage in steel fiber reinforced concrete, the standard multifractal method and multifractal detrended fluctuation analysis (MFDFA) are used to analyze the multifractal characteristics of acoustic emission (AE) signals. The results show that the AE signal time series is a long-range correlation process determined by the internal self-similarity mechanism, displaying an ordered multifractal distribution. As the steel fiber content increases, the regularity of AE signals improves while their variability decreases. The AE multifractal spectral width (∆ 𝛂) initially decreases and then increases, while ∆Ä shows a trend of increasing and then decreasing. The AE sequence distribution function demonstrates extremely strong horizontal symmetry, and its scale-free interval increases significantly compared to the 0–80% peak stress stage. The absolute value of the logarithmic error of the distribution function under the same measurement scale is accurate to 10–5. The local Hurst index drops significantly and reaches the minimum value, which can be used as a precursor to the axial tensile failure of steel fiber reinforced concrete.