Orthotropic elastic constants and tensile strength of extrusion-based additively manufactured carbon/carbon composites after polymer infiltration and pyrolysis

Abstract

This study was aimed at obtaining orthotropic elastic constants and tensile strengths of extrusion-based additively manufactured (EDAM) carbon/carbon (C/C) composites. Micro-computed tomography (µCT) data was coupled with impulse excitation data and Mori-Tanaka homogenization- based microstructural modeling to analyze 50 wt% short carbon fiber-loaded polyphenylene sulfide (PPS)-based C/C composites. After five polymer infiltration and pyrolysis cycles, the elastic constants and average tensile strength were found to be E₁ = 30.48 GPa, E₂ = 17.85 GPa, E₃ = 12.34 GPa, G₂₃ = 5.57 GPa, G₁₃ = 6.65 GPa, G₁₂ = 9.19 GPa, ν₂₃ = 0.28, ν₁₃ = 0.25, ν₁₂ = 0.26, and σ_T = 12.71 MPa, respectively. The results were unique to the fiber orientation induced during 3D printing and pore volume fraction achieved with densification and highlights the Mori-Tanaka- based microstructural modeling as a beneficial tool for capturing the fiber architecture- and process- dependent behavior of C/C composites.