Estimation of Mechanical Characterization of Woven CFRTP Under Tensile Loading Based on Acoustic Emission

The demand of carbon fiber-reinforced thermoplastic (CFRTP) materials is increasing, however, much less work has been done on CFRTP which contains matrix having high formability such as polyamide. We evaluated the mechanical characterization of damage development in CFRTP by conventional tows and spread tows. The quasi-static tensile tests were carried out with using DIC (digital image correlation) system to estimate the full field strain and AE (acoustic emission) sensors for measurement of the acoustic emission features. The CFRTP specimens were also investigated with optical microscope to clarify the difference of damage. The fiber debonding and delamination were shown in CF (with spread tows)/PA composites and the damage in weft yarn covered a wide range of test specimens. It is suggested that the mechanical characterization of damage is affected by fiber opening. This may also be explained by AE events. In weft yarn of CF (with conventional tows)/PA composites, we can observe transverse cracks and cracks which propagate in parallel with loading direction. From these results, the damage development of woven composites is sensitive to the form of fiber bundles and the properties of the matrix.