2015 Volume 64 Issue 12 Pages 1010-1017
In order to evaluate the effect of carbon fiber reinforced thermoplastic (CFRTP) forming temperature on the flexural strength in a non-destructive inspection, the relationship between the flexural strength and the hardness using pendulum hardness tester was investigated in the CFRTP laminated sheets molded at some different temperatures. Carbon fiber of plain weave and acrylic resin (PMMA) were used as reinforcement and matrix, respectively. The laminated sheet was formed by hot pressing. As a result, the flexural strength increased with increasing forming temperature. The new damping hardness (HDH) measured by the pendulum type hardness tester showed a good correlation with the flexural strength. In the laminated sheet formed at low temperature, the damping hardness measured at different position exhibited large deviation. This variation is due to the random array of fiber bundles. Therefore the homogeneity and the mechanical properties of CFRTP can be estimated in a non-destructive testing by the damping hardness measured at a number of positions.