Micro-CT analysis of internal geometry of chopped carbon fiber tapes reinforced thermoplastics

Adequate characterization of the internal geometry of random fiber composites for prediction of their properties requires acquisition and analysis of vast amount of data. The present work proposes a method to measure and quantify the internal geometry of ultra-thin chopped carbon fiber tape reinforced thermoplastics (UT-CTT), a kind of randomly oriented strands, using the X-ray micro-CT. The two-scale fiber orientation distributions (orientation of the tapes and of the fibers inside the tapes), tape morphology, 3D structure and orientation misalignment were characterized using a specialized image processing methodology. The results indicate that the applied method can provide detailed information like primary orientation directions, tape waviness and splitting of the internal geometry of UT-CTT. UT-CTTs produced with different molding pressure were studied to confirm the capability of the methodology in distinguishing subtle structure changes caused by different molding conditions.