Calibration of acoustic emission sensors

0481988 - GFÚ 2018 RIV CZ eng C - Konferenční příspěvek (zahraniční konf.)
Kolář, Petr - Petružálek, Matěj
Calibration of acoustic emission sensors.
Technical Computing Prague 2017. 24rd Annual Conference Proceedings. Prague: University of Chemistry and Technology, 2017 - (Byron, P.), s. 1-6. ISBN 978-80-7592-002-7. ISSN 2336-1662.
[Technical Computing Prague 2017 /24./. Praha (CZ), 08.11.2017-08.11.2017]
Grant CEP: GA ČR(CZ) GA16-03950S
Institucionální podpora: RVO:67985530 ; RVO:67985831
Klíčová slova: acoustic emission * sensors calibration * ultrasonic sounding
Obor OECD: Volcanology; Geology (GLU-S)

Measurement of acoustic emission (AE) during laboratory experiments – rock sample loading - is an important tool for study of material mechanical properties as well as understanding of modes of its failure. For correct data processing it is necessary to calibrate used AE sensors. The calibration constants can depend on property of individual sensors, on their contact conditions, etc. As there can be a deformation induced charge in sensor contact condition, the calibration constants may vary with time. AE sources can be modeled (in the same way as natural earthquakes) as double couple sources with use of moment tensor (MT) formalism (3x3 symmetric tensor, i.e. 6 independent values, the problem is linear). We adopted method, which enable calibration of an individual station of a seismic network. The method is based on simultaneous determination of MTs and calibration constant(s). During the experiment there were repeatedly measured velocities of elastic waves by ultrasonic sounding, when AE sensors cyclically acted as sources. We processed this data and for each cycle determined calibration constant for all the sensors but one, which is supposed to be 1. The source is supposed to be of single force type, which further reduces number of determined parameters. The evaluation was performed cyclically for all the sensors, the final calibration constants are then the mean values.
Trvalý link: http://hdl.handle.net/11104/0277406