Characterization of cavitation based on autocorrelation of acoustic emissions

2013 ◽  
Author(s):  
Miklós Gyöngy ◽  
Carl Jensen
Keyword(s):  
Acoustic Emissions

scholarly journals A Minimal Metric for the Characterization of Acoustic Noise Emitted by Underwater Vehicles

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6644
Author(s):  
Giacomo Picardi ◽  
Clara Borrelli ◽  
Augusto Sarti ◽  
Giovanni Chimienti ◽  
Marcello Calisti
Keyword(s):  
Acoustic Noise ◽  
Acoustic Emissions ◽  
Remotely Operated Vehicles ◽  
Underwater Robots ◽  
Acoustic Disturbance ◽  
Marine Fauna ◽  
Acoustic Data

Underwater robots emit sound during operations which can deteriorate the quality of acoustic data recorded by on-board sensors or disturb marine fauna during in vivo observations. Notwithstanding this, there have only been a few attempts at characterizing the acoustic emissions of underwater robots in the literature, and the datasheets of commercially available devices do not report information on this topic. This work has a twofold goal. First, we identified a setup consisting of a camera directly mounted on the robot structure to acquire the acoustic data and two indicators (i.e., spectral roll-off point and noise introduced to the environment) to provide a simple and intuitive characterization of the acoustic emissions of underwater robots carrying out specific maneuvers in specific environments. Second, we performed the proposed analysis on three underwater robots belonging to the classes of remotely operated vehicles and underwater legged robots. Our results showed how the legged device produced a clearly different signature compared to remotely operated vehicles which can be an advantage in operations that require low acoustic disturbance. Finally, we argue that the proposed indicators, obtained through a standardized procedure, may be a useful addition to datasheets of existing underwater robots.

scholarly journals Damage Characterization of Bio and Green Polyethylene–Birch Composites under Creep and Cyclic Testing with Multivariable Acoustic Emissions

Materials ◽  
2015 ◽  
Vol 8 (11) ◽  
pp. 7322-7341 ◽  
Author(s):  
Alencar Bravo ◽  
Lotfi Toubal ◽  
Demagna Koffi ◽  
Fouad Erchiqui
Keyword(s):  
Acoustic Emissions ◽  
Cyclic Testing ◽  
Damage Characterization

scholarly journals Extensive characterization of seismic laws in acoustic emissions of crumpled plastic sheets

2016 ◽  
Vol 114 (5) ◽  
pp. 59002 ◽  
Author(s):  
Leandro S. Costa ◽  
Ervin K. Lenzi ◽  
Renio S. Mendes ◽  
Haroldo V. Ribeiro
Keyword(s):  
Acoustic Emissions

Tensile characterization of graphene nanoplatelets (GNP) mortar using acoustic emissions

2020 ◽  
Vol 25 ◽  
pp. 101433 ◽  
Author(s):  
Zhangfan Jiang ◽  
Muhammad M. Sherif ◽  
Guohua Xing ◽  
Osman E Ozbulut
Keyword(s):  
Acoustic Emissions ◽  
Graphene Nanoplatelets ◽  
Tensile Characterization

Avalanche Behaviour in Microfracturing Process of 3-D Brittle Disordered Material

2005 ◽  
Vol 297-300 ◽  
pp. 2567-2572 ◽  
Author(s):  
De Shen Zhao ◽  
Tao Xu ◽  
Chun An Tang ◽  
Hou Quan Zhang ◽  
Zheng Zhao Liang
Keyword(s):  
Uniaxial Compression ◽  
Crack Nucleation ◽  
Process Analysis ◽  
Failure Process ◽  
Acoustic Emissions ◽  
Peak Stress ◽  
Disordered Materials ◽  
Avalanche Behavior ◽  
Fracturing Process

Using a newly-developed Material Failure Process Analysis code (MFPA3D), the micro-fracturing process and the avalanche behavior characterization of brittle disordered materials such as rock or concrete is numerically studied under uniaxial compression and tension. It is found that, due to the heterogeneity of the disordered material, there is an avalanche behavior in the microcrack coalescence process. Meanwhile, a hierarchy of avalanche events also numerically observed though a study of numerically obtained acoustic emissions or seismic events. Numerical simulations indicate that macro-crack nucleation starts well before the peak stress is reached and the crack propagation and coalescence can be traced, which can be taken as a precursory to predict the macro-fracture of the brittle disordered materials. In addition, the numerically obtained results also reveal the presence of residual strength in the post-peak region and the resemblance in the stress-strain curves between uniaxial compression and tension.

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