Experimental Investigations on Non-Linear Slow Dynamics of Damaged Materials: Correlation with Acoustic Emission

2008 ◽  
Author(s):  
M. Bentahar ◽  
A. Marec ◽  
R. El Guerjouma ◽  
J.-H. Thomas ◽  
V. Tournat ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Experimental Investigations ◽  
Slow Dynamics ◽  
Non Linear ◽  
Damaged Materials

Fast and Slow Dynamics in Damaged Materials: Correlation to Acoustic Emission

2008 ◽  
Vol 123 (5) ◽  
pp. 3398-3398
Author(s):  
Mourad Bentahar ◽  
Anne Marec ◽  
Rachid El Guerjouma ◽  
Jean‐Hugh Thomas
Keyword(s):  
Acoustic Emission ◽  
Slow Dynamics ◽  
Damaged Materials

Theorical Analysis of Leakage in High Pressure Pipe Using Acoustic Emission Method

2012 ◽  
Vol 445 ◽  
pp. 917-922 ◽  
Author(s):  
Saman Davoodi ◽  
Amir Mostafapour
Keyword(s):  
High Pressure ◽  
Acoustic Emission ◽  
Degrees Of Freedom ◽  
Oil And Gas ◽  
Pipe Wall ◽  
Leak Detection ◽  
Stress Waves ◽  
Motion Equation ◽  
Non Linear ◽  
Acoustic Emission Test

Leak detection is one of the most important problems in the oil and gas pipelines. Where it can lead to financial losses, severe human and environmental impacts. Acoustic emission test is a new technique for leak detection. Leakage in high pressure pipes creates stress waves resulting from localized loss of energy. Stress waves are transmitted through the pipe wall which will be recorded by using acoustic sensor or accelerometer installed on the pipe wall. Knowledge of how the pipe wall vibrates by acoustic emission resulting from leakage is a key parameter for leak detection and location. In this paper, modeling of pipe vibration caused by acoustic emission generated by escaping of fluid has been done. Donnells non linear theory for cylindrical shell is used to deriving of motion equation and simply supported boundary condition is considered. By using Galerkin method, the motion equation has been solved and a system of non linear equations with 6 degrees of freedom is obtained. To solve these equations, ODE tool of MATLAB software and Rung-Kuta numerical method is used and pipe wall radial displacement is obtained. For verification of this theory, acoustic emission test with continues leak source has been done. Vibration of wall pipe was recorded by using acoustic emission sensors. For better analysis, Fast Fourier Transform (FFT) was taken from theoretical and experimental results. By comparing the results, it is found that the range of frequencies which carried the most amount of energy is same which expresses the affectivity of the model.

scholarly journals Acoustic monitoring of a prestressed concrete beam reinforced by adhesively bonded composite

2018 ◽  
Vol 199 ◽  
pp. 09013
Author(s):  
Sylvain Chataigner ◽  
Laurent Gaillet ◽  
Yannick Falaise ◽  
Jean-François David ◽  
Richard Michel ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Concrete Structures ◽  
Experimental Investigations ◽  
Adhesively Bonded ◽  
Shear Tests ◽  
Prestressed Concrete Beam ◽  
Bonded Composite ◽  
Composite Reinforcement

The use of adhesively bonded composite reinforcement is relatively widely used for concrete structures. Yet, some questions remain regarding its use in the case of prestressed concrete structures especially in relation with the influence of existing cracking and the verification of the encountered damage phenomena at real scale. French National Organism CEREMA with the help of French motorway bridge owners association ASFA and French National Research Organism IFSTTAR realized several real size experimental investigations of an old prestressed concrete beam coming from a deconstructed bridge to answer these questions (Project CLERVAL). Both flexure and shear tests up to failure were carried out and several measurement methods were used to understand the role of the composite reinforcement on the behavior of the structure and the damage scenario. Acoustic emission was one of these methods and two different systems were investigated. The proposed communication will first describe the two used acoustic systems and their dedication (localized acoustic emission and overall acoustic survey). A specific development will then be presented aiming at optimizing the obtained acoustic phenomena localization taking into account the anisotropy of the prestressed concrete beam. Finally, main results will then be presented for both flexure and shear tests.

Experimental investigations into acoustic emission in coal samples under uniaxial loading

2004 ◽  
Vol 40 (5) ◽  
pp. 458-464 ◽  
Author(s):  
V. L. Shkuratnik ◽  
Yu. L. Filimonov ◽  
S. V. Kuchurin
Keyword(s):  
Acoustic Emission ◽  
Uniaxial Loading ◽  
Experimental Investigations

scholarly journals THE HARMONIC COMPOSITION OF CURRENT IN ZERO-WORKING WIRE WITH NON-LINEAR LOAD

2021 ◽  
Vol 22 (1) ◽  
pp. 191-200
Author(s):  
Igor Yudaev ◽  
Evgeny Rud ◽  
Mikhail Yundin ◽  
Tamara Ponomarenko ◽  
Aleksandra Isupova
Keyword(s):  
Power Transmission ◽  
Network Flows ◽  
Electrical Measuring ◽  
Frequency Characteristics ◽  
Experimental Investigations ◽  
Measuring Instruments ◽  
Negative Consequences ◽  
Linear Load ◽  
Non Linear ◽  
Non Linear Load

The purpose of this study was experimental investigations and a study of the nature of the change in the main harmonic components of the current in the neutral working wire of a three-phase four-wire network with a voltage of 0.38 kV. The study of the amplitude-phase-frequency characteristics of currents flowing in an electric network with a predominant non-linear load is one of the most urgent tasks, the solution of which will increase the efficiency of electric power transmission and eliminate the negative consequences due to the current flow in a zero-working wire in the network at 0.38 kV. To study the effect of load changes on the amplitude-phase-frequency characteristics of currents in the linear and zero working wires at the input of the load node, measurements were carried out by certified electrical measuring instruments namely, the “Resource-UF2M” and “Hioki 3196”. With these devices, the phase voltages at the input to the load node were measured. The analysis of the results obtained for the load node whose power was formed mainly by a lighting system with fluorescent and LED lamps and a system of office electrical receivers (computers, copiers, printers, scanners, etc.) was performed. It can be concluded that a current comparable to the currents of the linear wires of the network flows from the load node with the predominant nonlinear power receivers through the zero-working wire. At the same time, in the zero-working wire of the network, the third harmonic current prevails over the main frequency currents. ABSTRAK: Tujuan kajian ini adalah penyelidikan eksperimental dan kajian mengenai sifat perubahan komponen harmonik utama arus dalam wayar kerja neutral rangkaian empat wayar tiga fasa dengan voltan 0.38 kV. Kajian mengenai ciri-ciri frekuensi-amplitud-fasa arus yang mengalir dalam rangkaian elektrik dengan beban bukan linear yang dominan adalah salah satu tugas yang paling mendesak, penyelesaiannya akan meningkatkan kecekapan penghantaran tenaga elektrik dan menghilangkan akibat negatif yang disebabkan ke arus semasa dalam wayar sifar bekerja di rangkaian pada 0.38 kV. Untuk mengkaji kesan perubahan beban pada ciri frekuensi-fasa frekuensi arus dalam wayar linier dan sifar pada input nod beban, pengukuran dilakukan oleh alat pengukur elektrik yang disahkan iaitu, "Resource-UF2M" dan "Hioki 3196". Dengan peranti ini, voltan fasa pada input ke simpul beban diukur. Analisis hasil yang diperoleh untuk simpul beban yang kekuatannya dibentuk terutama oleh sistem pencahayaan dengan lampu pendarfluor dan LED dan sistem penerima elektrik pejabat (komputer, mesin fotokopi, pencetak, pengimbas, dll.). Dapat disimpulkan bahawa arus yang setanding dengan arus wayar linier rangkaian mengalir dari nod beban dengan penerima kuasa bukan linier yang dominan melalui wayar sifar. Pada masa yang sama, dalam wayar sifar rangkaian, arus harmonik ketiga berlaku berbanding arus frekuensi utama.

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