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Shear-tensile crack as a source model for laboratory acoustic emission

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    0500588 - GLÚ 2019 RIV US eng C - Conference Paper (international conference)
    Petružálek, Matěj - Lokajíček, Tomáš - Svitek, Tomáš - Jechumtálová, Zuzana - Kolář, Petr - Adamová, Petra - Šílený, Jan
    Shear-tensile crack as a source model for laboratory acoustic emission.
    52nd U.S. Rock Mechanics/Geomechanics Symposium. s. l.: American Rock Mechanics Association, 2018. ISBN N.
    [US Rock Mechanics/Geomechanics Symposium /52./. Seattle (US), 17.06.2018-20.06.2018]
    R&D Projects: GA ČR(CZ) GA16-03950S; GA ČR(CZ) GA18-08826S
    Institutional support: RVO:67985831 ; RVO:67985530
    Keywords : compression testing * compressive strength * cracks * inverse problems * rock mechanics * acoustic emission testing
    OECD category: Geology; Geology (GFU-E)

    Here, a shear-tensile crack (STC) model is presented as suitable for Acoustic Emission (AE) events and compared to a traditional MT (Moment Tensor) approach. Experimental data was obtained from a uniaxial compression test performed on a Westerly Granite (WG) specimen using a 14 channel AE monitoring system. The STC is a physical source, which describes anticipated fracture modes: Shear-slip and opening/closing tensile crack. It is described by fewer parameters (5 instead of the 6 for MT), which is essential for solving the inverse problem. The presented STC procedure was tested on 38 AE events selected over a range of 50 – 98% for the uniaxial compressive strength. As compared to the MT, the STC model displayed a similar fit for input data while providing far smaller confidence regions. The results indicate a more certain determination for the mechanism orientation and improved reliability for the decomposition components. In addition, use of STC model allowed better distinction between tension and shear type for AE events, which may be a crucial for recognizing an approaching failure. For our experiment, application of the STC model proved to be useful for recognizing the threshold of unstable microcracking.
    Permanent Link: http://hdl.handle.net/11104/0292687

     
     
Number of the records: 1