A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Measuring and localizing acoustic emission events in snow prior to fracture
https://orcid.org/0000-0003-2364-5760
https://orcid.org/0000-0001-5076-2968
Abstract Acoustic emissions (AE) are transient elastic waves produced by a sudden redistribution of stress in a material caused by changes in the internal structure. In other natural, heterogeneous materials monitoring AE has proven to be a valuable tool for stability estimation and failure prediction. After studying the characteristics of ultrasonic wave propagation in snow, we measured the acoustic emission signals during snow loading experiments in a cold laboratory. Using snow columns we found that most energy of an artificial acoustic signal was transmitted at 31kHz. Best coupling to snow was achieved by attaching the AE sensors with silicone adhesive to thin aluminium plates which were then frozen to the snow. Localizing AE events during fracture of layered snow samples showed that the AE originated within the weakest layer, i.e. the relevant layer for snow failure. For finding an indication of imminent failure, we analysed the exponent β of the cumulative size-frequency distribution (‘survival curve’) of event energy. At the occurrence of instabilities, the β-curve deviated from steady behaviour and exhibited distinct ‘drops’, indicating that the power law behaviour of the distribution was not fulfilled anymore. Studying the temporal evolution of the exponent β might therefore provide useful information about snowpack stability also in the field—provided that the AE signals are not too strongly attenuated and can be detected in time before catastrophic failure occurs.
Highlights Best coupling of AE sensors to snow by gluing sensors to aluminium plates Frequency analysis: ultrasonic frequency well transmitted within snow: 30kHz AE signal localization: AE signals stem from fracturing layer Exponent β might serve as an indicator for imminent snow failure AE certainly has potential to be used for estimating snow stability
Measuring and localizing acoustic emission events in snow prior to fracture
https://orcid.org/0000-0003-2364-5760
https://orcid.org/0000-0001-5076-2968
Abstract Acoustic emissions (AE) are transient elastic waves produced by a sudden redistribution of stress in a material caused by changes in the internal structure. In other natural, heterogeneous materials monitoring AE has proven to be a valuable tool for stability estimation and failure prediction. After studying the characteristics of ultrasonic wave propagation in snow, we measured the acoustic emission signals during snow loading experiments in a cold laboratory. Using snow columns we found that most energy of an artificial acoustic signal was transmitted at 31kHz. Best coupling to snow was achieved by attaching the AE sensors with silicone adhesive to thin aluminium plates which were then frozen to the snow. Localizing AE events during fracture of layered snow samples showed that the AE originated within the weakest layer, i.e. the relevant layer for snow failure. For finding an indication of imminent failure, we analysed the exponent β of the cumulative size-frequency distribution (‘survival curve’) of event energy. At the occurrence of instabilities, the β-curve deviated from steady behaviour and exhibited distinct ‘drops’, indicating that the power law behaviour of the distribution was not fulfilled anymore. Studying the temporal evolution of the exponent β might therefore provide useful information about snowpack stability also in the field—provided that the AE signals are not too strongly attenuated and can be detected in time before catastrophic failure occurs.
Highlights Best coupling of AE sensors to snow by gluing sensors to aluminium plates Frequency analysis: ultrasonic frequency well transmitted within snow: 30kHz AE signal localization: AE signals stem from fracturing layer Exponent β might serve as an indicator for imminent snow failure AE certainly has potential to be used for estimating snow stability
Measuring and localizing acoustic emission events in snow prior to fracture
https://orcid.org/0000-0003-2364-5760
https://orcid.org/0000-0001-5076-2968
Abstract Acoustic emissions (AE) are transient elastic waves produced by a sudden redistribution of stress in a material caused by changes in the internal structure. In other natural, heterogeneous materials monitoring AE has proven to be a valuable tool for stability estimation and failure prediction. After studying the characteristics of ultrasonic wave propagation in snow, we measured the acoustic emission signals during snow loading experiments in a cold laboratory. Using snow columns we found that most energy of an artificial acoustic signal was transmitted at 31kHz. Best coupling to snow was achieved by attaching the AE sensors with silicone adhesive to thin aluminium plates which were then frozen to the snow. Localizing AE events during fracture of layered snow samples showed that the AE originated within the weakest layer, i.e. the relevant layer for snow failure. For finding an indication of imminent failure, we analysed the exponent β of the cumulative size-frequency distribution (‘survival curve’) of event energy. At the occurrence of instabilities, the β-curve deviated from steady behaviour and exhibited distinct ‘drops’, indicating that the power law behaviour of the distribution was not fulfilled anymore. Studying the temporal evolution of the exponent β might therefore provide useful information about snowpack stability also in the field—provided that the AE signals are not too strongly attenuated and can be detected in time before catastrophic failure occurs.
Highlights Best coupling of AE sensors to snow by gluing sensors to aluminium plates Frequency analysis: ultrasonic frequency well transmitted within snow: 30kHz AE signal localization: AE signals stem from fracturing layer Exponent β might serve as an indicator for imminent snow failure AE certainly has potential to be used for estimating snow stability
Measuring and localizing acoustic emission events in snow prior to fracture
Reiweger, Ingrid (author) / Mayer, Klemens (author) / Steiner, Kevin (author) / Dual, Jürg (author) / Schweizer, Jürg (author)
Cold Regions, Science and Technology ; 110 ; 160-169
2014-12-02
10 pages
Article (Journal)
Electronic Resource
English
Measuring and localizing acoustic emission events in snow prior to fracture
| Online Contents | 2015
Localizing Acoustic-Emission Signals in Metal Structures
| British Library Online Contents | 1997
Acoustic Emission Analysis of Nanoindentation-Induced Fracture Events
| British Library Online Contents | 2006
Acoustic-emission study of the possibilities of localizing flaws of a welded joint during cooling
| British Library Online Contents | 2009
Fracture mechanics and acoustic emission
| TIBKAT | 2001