Abstract
In the present paper, residual strains in matrix resin were monitored by embedded FBG sensors during room-temperature cure and post-cure processes by applying various temperature profiles. From the experimental results, it was found that final residual strain became smaller if post-cure process started faster. In order to investigate the strain behavior of resin during all cure processes, a viscoelastic FE analysis of resin in which an FBG sensor was embedded was conducted. The strain behavior calculated by the FE analysis agreed very well with the experimental results quantitatively. The FE analytical results showed that strain behavior of the embedded sensor is governed by thermal strain, cure shrinkage strain and viscoelastic properties of resin. Since cure shrinkage strain and viscoelastic stiffness are functions of degree of cure, it can be said that a relationship between degree of cure and heating profile plays the most significant role in generation of the final residual strain. The present technique is useful to predict residual strain of inserts embedded in resin after molding process.
