Laser scanning vibrometry (LSV) is a non-contact technique for precise measurements of elastic wave parameters. In particular, the measurements of the wave velocity and dissipation deliver information on a material’s stiffness and imperfections. In this paper, LSV was applied to monitor the stiffness and density of defects in composite laminate specimens cured at various exposures to microwave radiation. The specimens were supported by nylon wires and excited by a loudspeaker. Its driving frequency was swept and the frequency response of the specimenswas measured by a laser vibrometer. The frequency shift of the fundamental flexural mode due to stiffness variation was measured as a function of the microwave exposure. To evaluate the dissipation factor, which is related to the density of defects, a short pulse was used for acoustic excitation. The temporal decay of the vibrations (reverberation) was measured by LSV and interpolated with an exponential function. The results obtained enable monitoring of the deterioration of the composite properties with the increase in the microwave exposure.

A laser scanning vibrometer for the monitoring of stiffness and density defects in fibre-reinforced plastics

VISCO, Annamaria;TORRISI, Lorenzo
2010

Abstract

Laser scanning vibrometry (LSV) is a non-contact technique for precise measurements of elastic wave parameters. In particular, the measurements of the wave velocity and dissipation deliver information on a material’s stiffness and imperfections. In this paper, LSV was applied to monitor the stiffness and density of defects in composite laminate specimens cured at various exposures to microwave radiation. The specimens were supported by nylon wires and excited by a loudspeaker. Its driving frequency was swept and the frequency response of the specimenswas measured by a laser vibrometer. The frequency shift of the fundamental flexural mode due to stiffness variation was measured as a function of the microwave exposure. To evaluate the dissipation factor, which is related to the density of defects, a short pulse was used for acoustic excitation. The temporal decay of the vibrations (reverberation) was measured by LSV and interpolated with an exponential function. The results obtained enable monitoring of the deterioration of the composite properties with the increase in the microwave exposure.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11570/1906657
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? 0
social impact