About this Abstract |
Meeting |
2024 ASC Technical Conference, US-Japan Joint Symposium, D30 Meeting
|
Symposium
|
2024 ASC Technical Conference, US-Japan Joint Symposium, D30 Meeting
|
Presentation Title |
Evaluation of the Permeability of Carbon/Carbon Composites to Characterize the Pyrolysis and Re-Infiltration of the Carbon Precursor During Densification |
Author(s) |
Tania Lavaggi, John W. Gillespie, Suresh Advani |
On-Site Speaker (Planned) |
Tania Lavaggi |
Abstract Scope |
To manufacture fully densified Carbon/Carbon composites it is necessary to iterate in several cycles the processes of pyrolysis and infiltration of a high char yielding thermoset polymer as carbon matrix precursor. During pyrolysis the matrix precursor degrades generating gas, and porosity is created within the composite. Successful pyrolysis occurs when the generated gas is vented through the open connected pores. Permeability is an effective measure of open porosity and is the critical property governing the pressure and time for re-infiltration of resin into the Carbon/Carbon composite during densification iterations. Correlating porosity and permeability is necessary for numerical simulations of the densification processes to reduce production time.
In this work, benzoxazine-based Carbon/Carbon composites are pyrolyzed following thermal cycles designed from kinetic analysis of the degradation reactions of the carbon precursor. The permeability of the material is measured via a pulse-decay experiment and it is correlated with the porosity development during degradation, which is characterized by pycnometry and X-ray computed tomography. The X-ray images of the samples are used to generate a numerical model of the microstructure. The measured permeability serve as inputs of a finite element/control volume software called Liquid Injection Molding Simulation (LIMS), which allows the selection of gate and vent locations and applied pressure and viscosity of the resin to simulate the infiltration of the fiber preform and predict the pore regions that are occupied by the resin. The output is the unfilled pores. Sensitivity studies on the injecting parameters help identify the best strategies for the re-infiltration process. |
Proceedings Inclusion? |
Definite: Post-meeting proceedings |