Characterization of Mechanical Performance of Composites Fabricated Using Innovative Carbon Fiber Wet Laid Process

Abstract

Recent innovation in production of optimized nonwoven wet laid (WL) carbon fiber (CF) mats raised the question of optimal translation of the performance and isotropy into composites formed through these dry preforms. This work explores the mechanical behavior of composites produced from WL-CF mats in conjunction with the microstructure predicted through Object Oriented Finite Element Analysis (OOF). The mats used for the composites were prepared in two dispersion regimes using 25.4 mm long CF. The mixing regimes discussed in the author’s previous work, are identified as Method 1 for the traditional processing regime and Method 2 for the innovative regime that provided optimal nonwoven WL-CF mats. Composite panels from Method 2 mats showed a normalized tensile strength increase of 52% over those from Method 1 panels. Reproducibility analysis of composites made from Method 2 mats demonstrated a standard deviation of 2% in fiber weight content, 2% in tensile modulus and 9% in tensile strength, while composites made from Method 1 mats demonstrated a standard deviation of 5% in fiber weight content, 5% in tensile modulus and 17% in tensile strength. Systematic study of the microstructure and its analysis through OOF confirmed the isotropy translation of mats produced through method 2 to the composites. This study validated the hypothesis that optimal nonwoven mats lead to a well-balanced composite with optimal performance and that non-optimal nonwoven mats do not pack into a well-balanced composite.