Monitoring the effect of post-cure on the performance of RTM processing composites

The performance of composites manufactured by resin transfer molding (RTM) processing can be monitored by fiber Bragg grating (FBG) sensor during post-curing procedure. The effects of post-curing on the strain free temperature, glass transition temperature, residual strain, coefficient of thermal expansion of the composites are monitored by the temperature/strain double-FBG sensors. The effect of mould material on the coefficient of thermal expansion is also discussed. The test results indicate that the strain free temperature and the glass transition temperature change from 189.0°C and 189.4°C to 200.2°C and 204.0°C, respectively, the outer residual strain changes from -597.7 μΕ to -671.5 μΕ, the outer coefficient of thermal expansion changes from 5.248×10-6/°C to 4.275×10-6/°C after the post-curing process. Therefore, post-cure can improve the performance of composites.