Application of acoustic emission technique to monitoring of degradation of fiber reinforced composites

Tomasz Lusa, Krystian Paradowski, Marcin Ciesielski, Danuta Witemberg-Perzyk, Krzysztof J. Kurzydłowski 1, 2, 3, 5 Politechnika Warszawska, Wydział Inżynierii Materiałowej, Zakład Projektowania Materiałów, ul. Wołoska 141, 02-507 Warszawa, Poland 4 Politechnika Warszawska, Wydział Inżynierii Produkcji, Instytut Mechaniki i Konstrukcji, ul. Narbutta 85, 02-524 Warszawa, Poland

Quarterly No. 4, 2008 pages 379-384

DOI:

keywords: acoustic emission, degradation, fibre reinforced composite

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abstract The paper presents investigations of tensile strain rate influence on structural degradation of glass fabric reinforced polycarbonate composite with acoustic emission (AE) technique. Tests were carried out with two different types of applied load. AE characteristics of signals acquired during tensile tests showed differences in types of phenomena occurring in material’s structure during deformation. These phenomena are related to an effect of material deformation history. Causes of this effect are processes taking place with different rate and with different value of stresses in microscale. Analysis of AE parameters in three ranges of the material plastic deformation showed an occurrence of two damage mechanisms which is clearly visible as high peaks at different frequencies. Samples under tension load according to A scheme showed large amount of signals with frequencies 150205 kHz. In the case of samples under tension load according to B scheme showed, domination of signals with frequencies 150250 kHz, moreover there occur much more signals with frequencies from range 300550 kHz. Based on differences in frequencies of acquired signals, was found that that for investigated material occur two damage mechanisms related with type of load scheme. Analysis of Acoustic Emission signals for samples related to different types of lad scheme, showed that effect of material deformation history has significant influence on it tensile strength. Estimation of Acoustic Emission changes for composite materials produced by plastic deformation give possibility to assume temporary stage of microstructure degradation. These results confirmed possibility of structural degradation monitoring of fiber reinforced composites using AE technique.