In this paper, the vibration performance and damage types of carbon fiber composite materials were investigated based on FBG sensing technology. The free end of a carbon fiber composite cantilever beam was hit by a falling ball to generate a resonance in the cantilever. The resonance frequency was measured and the damping loss factor was calculated based on which the vibration characteristic of the carbon fiber composite was analyzed. After that, a man-made damage (a small hole) was introduced into the cantilever and the resonance frequency was measured again. The result was compared with the frequency without damage, so that the damage type could be judged. The result provides a reference to the study of the vibration performance and damage monitoring of carbon fiber composite materials.
Dispersion-induced radio-frequency (RF) power degradation in the optical true time delay (OTTD) module implemented
by a broadband light source (BBLS) and a dispersion element is studied in this paper, both theoretically and
experimentally. Theoretical results indicate that compared with that using a tunable laser source (TLS), OTTD using a
BBLS suffers from extra power degradation, and that when the transfer function of the tunable optical filter (TOF) can
be approximated to be rectangular, at additional frequencies besides the power-vanishing frequencies in the case of using
TLS, the phenomenon of electrical power-vanishing can also be observed. Experiments using a TLS and a BBLS are
performed for comparison, and TOFs of different bandwidth are used. The electrical transfer functions are measured and
prove the conclusion of the theory. The electrical power-vanishing frequencies are provided and in good agreement with
the theoretical values.