scholarly journals Experimental study of the destruction in CFRP laminates at the macro-level by acoustic emission method

2021 ◽  
Vol 2131 (4) ◽  
pp. 042019
Author(s):  
P Severov
Keyword(s):  
Acoustic Emission ◽  
Stress Concentration ◽  
Mutual Arrangement ◽  
Mechanical State ◽  
Load History ◽  
Emission Method ◽  
Cfrp Laminates ◽  
Destruction Zone ◽  
The Moment ◽  
High Degree

Abstract The author conducted experiments using the method of acoustic emission under uniaxial tension of specimens of CFRP laminates with different stacking, geometry and stress concentration. The influence of a mutual arrangement of the material destruction zone and the extensometer installation site on the nonlinear deformation is revealed. It is shown that the damage accumulation process is highly informative when determining the energy of AE pulses. The possibility of visualizing the formation and development of destruction zones in orthogonal directions, as well as the possibility of determining the moment of crack start from the apex of the notch during splitting, is established. The mechanism of alternating stress relaxation in two developed zones of destruction is revealed. The paper shows a high degree of correlation between mechanic and acoustic-emission events. Finally, the author suggests assessing the mechanical state of material with the account of obtained damages by the degree of its integrity (one to zero) depending on the load history, its individual geometric features and stress concentration.

scholarly journals DEFINITION OF CONTACT STRESS IN FRICTION UNITS ON THE BASIS OF THE ACOUSTIC EMISSION METHOD

Aviation ◽  
2009 ◽  
Vol 13 (3) ◽  
pp. 72-77 ◽  
Author(s):  
Sergay Filonenko ◽  
Viacheslav Stadnychenko ◽  
Anzhelika Stakhova
Keyword(s):  
Acoustic Emission ◽  
Contact Stress ◽  
Friction Unit ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Linear Character ◽  
The Moment ◽  
Definition Of ◽  
Experimental Researches ◽  
Better Than

The following results of acoustic emission signals researches were obtained during the change in contact stress. It is shown that the theoretical regularity of change in average level of the acoustic emission resulting signal at contact stress has a linear character. Analogical regularity is received during experimental researches. It is showed that the sensitivity of the acoustic emission method and the precision of determining contact stresses are considerably better, than the tensometry method. The recording of the moment when friction unit seize begins is also considerably more precise. Santrauka Nagrineti akustines emisijos galutinio signalo rezultatai kintant kontaktiniams itempimams. Nustatyta, kad akustines emisijos galutinio signalo vidutinio lygio kitimo teorine priklausomybe nuo kontaktiniu itempimu yra tiesine. Analogiška priklausomybe gauta ir eksperimento metu. Taip pat nustatyta, kad akustines emisijos metodo jautrumas ir kontaktiniu itempimu nustatymo tikslumas yra kur kas geresnis nei tenzometrijos metodo. Be to, kur kas anksčiau fiksuojamas laiko momentas, kai pradeda strigti trinties mazgas.

scholarly journals Monitoring of the Impact of Lithium Nitrate on the Alkali–aggregate Reaction Using Acoustic Emission Methods

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Justyna Zapała-Sławeta ◽  
Grzegorz Świt
Keyword(s):  
Acoustic Emission ◽  
Initial Reaction ◽  
Lithium Nitrate ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Acoustic Activity ◽  
Initial Stage ◽  
Chemical Admixture ◽  
Different Characteristics ◽  
The Impact

The study analyzed the possibility of using the acoustic emission method to analyse the reaction of alkali with aggregate in the presence of lithium nitrate. Lithium nitrate is a chemical admixture used to reduce adverse effects of corrosion. The tests were carried out using mortars with reactive opal aggregate, stored under the conditions defined by ASTM C227. The acoustic activity of mortars with a corrosion inhibitor was referred to linear changes and microstructure of specimens in the initial reaction stages. The study found a low acoustic activity of mortars with lithium nitrate. Analysis of characteristic parameters of acoustic emission signals, combined with the observation of changes in the microstructure, made it possible to describe the corrosion processes. As the reaction progressed, signals with different characteristics were recorded, indicating aggregate cracking at the initial stage of the reaction, followed by cracking of the cement paste. The results, which were referred to the acoustic activity of reference mortars, confirmed that the reaction of opal aggregate with alkali was mitigated in mortars with lithium nitrate, and the applied acoustic emission method enabled the detection and monitoring of ASR progress.

Three-Point Bending Test Evaluation of Concrete Specimens by Non-Traditional Analysis of Acoustic Emission Method

2016 ◽  
Vol 837 ◽  
pp. 198-202
Author(s):  
Luboš Pazdera ◽  
Libor Topolář ◽  
Tomáš Vymazal ◽  
Petr Daněk ◽  
Jaroslav Smutny
Keyword(s):  
Acoustic Emission ◽  
Signal Analysis ◽  
Measurement Data ◽  
Bending Test ◽  
Test Evaluation ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Three Point Bending ◽  
Time Frequency ◽  
Emission Signal

The aim of the paper is focused on the analysis of the mechanical properties of the concrete specimens with plasticizer at three point bending test by the signal analysis of the acoustic emission signal. The evaluations were compared the measurement and the results obtained with theoretical presumptions. The Joint Time Frequency Analysis applied on measurement data and its evaluation is described. It is well known that the Acoustic Emission Method is a very sensitive method to determine active cracks into structure. However, evaluation of acoustic emission signals is very difficult. A non-traditional method was used to signal analysis of burst acoustic emission signals recorded during three point bending test.

Evaluation of Friction Phenomena of Brake Pads by Acoustic Emission Method

2014 ◽  
Vol 7 (2) ◽  
pp. 703-709 ◽  
Author(s):  
Kazuho Mizuta ◽  
Yukio Nishizawa ◽  
Koji Sugimoto ◽  
Katsuya Okayama ◽  
Alan Hase
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Brake Pads

scholarly journals Characterization of Fatigue Damage in 304L Steel by an Acoustic Emission Method

2013 ◽  
Vol 66 ◽  
pp. 651-660 ◽  
Author(s):  
A. Ould Amer ◽  
A.-L. Gloanec ◽  
S. Courtin ◽  
C. Touze
Keyword(s):  
Acoustic Emission ◽  
Fatigue Damage ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
304L Steel

Development of Corrosion Depth Evaluation Method in Steel Pipe by Acoustic Emission Method

2021 ◽  
Vol 70 (2) ◽  
pp. 40-46
Author(s):  
Takuya Kurihara ◽  
Matsuo Takuma ◽  
Taro Kono ◽  
Kaori Numata
Keyword(s):  
Acoustic Emission ◽  
Evaluation Method ◽  
Steel Pipe ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Corrosion Depth
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