Detection and suppression of transverse cracks in composite laminates with embedded FBG sensors and SMA film actuators

摘要

A small-diameter FBG sensor was embedded in 0°ply of a CFRP cross-ply laminate, and reflection spectra from the FBG sensor were measured at various tensile stresses. As a result, it was found that the small-diameter FBG sensors have a potential to detect the occurrence of transverse cracks in 90°ply through the change in the form of the spectrum, and to evaluate the crack density quantitatively by the spectrum width. On the other hand, pre-strained SMA films were embedded between laminas in CFRP laminates and heated. The effects of recovery stresses were demonstrated in the experiments and well predicted using the shear-lag analysis and the nonlinear constitutive equation of SMA films.