Stanford Acoustic Emission Data set_waveforms

The acoustic emission (AE) data set is from a triaxial compression test conducted in a triaxial loading vessel equipped with a network of AE sensors . In the compression test, a cylindrical Berea sandstone specimen (diameter: 25.14 mm; length: 49.45 mm) was increasingly loaded up to failure at an axial strain rate of 1.03×10-5 /s under a constant confining pressure of 5 MPa. During the axial loading process, AE waveforms were detected by ten PZT-5A compressional crystal sensors manufactured by Boston Piezo-Optics Inc. The setup uses an Elsys acquisition system to amplify, digitize and record the waveforms, which consists of an AE-Amp Pre-amplifier (model Amp-BU-20-AE) and a High-Speed Data Acquisition (model TranNET EPC) module. We set a 40 dB pre-amplification gain and 5 kHz – 2MHz bandpass filtering. The sampling rate of waveforms was 10 MHz. The time length of each waveform was 250 μs, comprising a pre-trigger length of 50 μs and a post-trigger length of 200 μs. Here, the term “trigger” refers to one channel of the AE system being activated once the acquired waveforms meet a triggering criterion set by the user. We set the trigger level at 0.5 V and the trigger mode to use the positive slope mode. After acquiring the AE data, we manually selected 49,212 waveforms containing P-wave arrival by using a P-wave arrival picking platform developed in-house.