2D microstructural modeling of transverse cracking during pyrolysis process of carbon fiber reinforced plastics

Kurzfassung

During the manufacturing process of carbon fiber based C/C-SiC composites, the phenolic resin of prepreg is converted to carbon through high temperature pyrolysis treatment. This step induces a high amount of porosity within the microstructure. The pore morphology varies from fine pores throughout the composite up to large crack channels with block-like, pretty dense C/C fiber matrix areas. The different crack formations during pyrolysis strongly depend on the fiber/matrix interface strength and temperature. In the present study, the formation of crack pattern is simulated in a FE-model with consideration of effects of fiber/matrix interface strength, fiber volume fraction, temperature change and other essential microstructural properties. The presented models are successfully able to simulate the material behavior and the consequent generation of cracks during pyrolysis process. Microstructure of the material has been then analyzed and compared with simulation results with the help of image segmentation techniques using Python. Based on the crack area distribution obtained from the SEM-analysis, microstructures can now be compared qualitatively as well as quantitatively.