DocumentCode :
2352370
Title :
5K-1 F.E.M. Simulation of Lamb Wave Propagation: Application to the Thermo-Oxidative Ageing of Carbon-Epoxy Plates
Author :
Gelebart, Y. ; Duflo, H. ; Duclos, J. ; Morvan, B.
Author_Institution :
Lab. d´´Acoustique Ultrasonore et d´´Electronique, Univ. du Havre, Le Havre
fYear :
2006
fDate :
2-6 Oct. 2006
Firstpage :
1165
Lastpage :
1168
Abstract :
Thermo-oxidative ageing of carbon-epoxy plates has been done for up to 9000 hours at two temperatures (160 and 180degC). Non-destructive evaluation by means of non contact ultrasonic methods has been tested to characterize the aged plates. It is shown that the phase velocity of the A0 and S0 Lamb modes is decreasing when ageing duration increases. Micrographs reveal the presence of oxidation cracks propagating from the free surfaces of the plate. The plates thus become inhomogeneous in the thickness. The propagation of the Lamb waves, in the aged plates, is simulated using a finite element model of an inhomogeneous and anisotropic plate. The excitation of several modes in a frequency range (chirp excitation) or a single mode at a chosen frequency (burst windowed excitation) is applied. To simulate the ageing of carbon-epoxy composite plates (8 plies), the elastic parameters are decreased in the two external plies. The results are then compared with experiments. Using this FE model, we demonstrate that this phenomenon is related to an important decrease of the C55 elastic parameter of the plate
Keywords :
ageing; anisotropic media; composite materials; cracks; finite element analysis; inhomogeneous media; plates (structures); surface acoustic waves; ultrasonic materials testing; 160 C; 180 C; 9000 h; FEM simulation; Lamb modes; Lamb wave propagation; anisotropic plate; burst windowed excitation; carbon-epoxy composite plates; chirp excitation; elastic parameters; finite element method; inhomogeneous plate; noncontact ultrasonic methods; nondestructive evaluation; oxidation cracks; phase velocity; thermo-oxidative ageing; Aging; Fatigue; Finite element methods; Frequency; Laminates; Nondestructive testing; Ovens; Oxidation; Surface cracks; Temperature;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Ultrasonics Symposium, 2006. IEEE
Conference_Location :
Vancouver, BC
ISSN :
1051-0117
Print_ISBN :
1-4244-0201-8
Electronic_ISBN :
1051-0117
Type :
conf
DOI :
10.1109/ULTSYM.2006.299
Filename :
4152155
Link To Document :
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