INVESTIGADORES
CHAPETTI mirco Daniel
artículos
Título:
Analysis of Breathing Cracks Using Vibrations
Autor/es:
G.E. CARR; L.F. JAUREGUIZAHAR; M.D. CHAPETTI
Revista:
EXPERIMENTAL TECHNIQUES
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2013 vol. 37 p. 32 - 40
ISSN:
0732-8818
Resumen:
The influence of half-ellipse-shaped fatigue cracks and machined throughthickness
cuts on the impact response of cantilever beam samples were
analysed using the Finite Element Method and compared to experimental
data for different crack depths. The effect of sample width was analysed for
geometries with fatigue cracks (aspect ratio a/c = 0.45) and through-thickness
cuts (rectangular cracks). The differences between both types of damage were
analysed numerically and experimentally. The effect of sample width was
studied and it was found that the behaviour of the cantilever with a fatiguecrack
approaches that of the saw cut sample when the fatigue crack reaches
the edges of the test piece. Acceleration data were analysed using the Fast
Fourier Transform algorithm and Power Density Spectra (PSD) were obtained.
For fatigue-cracked samples, harmonics of the frequencies of natural modes
of oscillation were found. Analytical modelling was done using a mass-springdamper
system for studying the bilinear behaviour of the stiffness element.
Harmonics found were assigned to the breathing behaviour of the crack. The
detection threshold using frequency shifts inspection was twice as high as using
spectral analysis. This would allow crack detection at half of the fatigue life of
the specimen.