Optimization of microstructures and mechanical properties of composite oriented strand board from reused prepreg

A prepreg strand layup method (mat-stacking) is presented to enhance the microstructure and mechanical properties of composite oriented strand board (COSB) produced with re-used prepreg scraps. Eight COSB panels were produced using two layup methods and four prepreg strand aspect ratios (1:1, 2:1, 5:1, and 10:1). All COSB panels were compression molded with the same carbon/epoxy system and process parameters, including cure cycle, temperature, and mold pressure. COSB void content, morphology, and distribution were characterized using microscopy and X-ray computed tomography (XCT). Tensile properties and failure modes of COSB panels exhibited a strong dependence on the strand layup method and the strand aspect ratio. Results demonstrated that COSB with lower coefficient of variation and useful mechanical properties can be produced with the proposed layup method and judicious selection of strand aspect ratio, yielding stiffness similar to continuous quasi-isotropic composites with up to 50% of the strength.