Fig. 2: Acoustic signals from compression tests of micropillars with a diameter of 8 μm.
From: Predicting plastic deformation of crystalline materials by deciphering acoustic emission
a A representative AE signal that constitutes of a few characteristic frequencies. The noise have a mean frequency of ~ 500 kHz. When an event occurs a short ( ~ 20 μs long) signal with a frequency of ~ 250 kHz emerges from the noise which is followed by a longer periodic pattern of frequency ~ 100 kHz. b The absolute value of the Fourier transform \({C}_{{\mathcal{F}}}\) of the frequency f averaged on several time windows centered on signals. The color-coding is consistent with the legend of panel (a) and it highlights the peaks corresponding to the characteristic frequencies. c Typical signals shifted with t0 such that their starting points coincide at t − t0 = 0. These curves demonstrate that the signals and the involved frequencies are rather similar despite their different amplitude/energy.
