Design of carbon fiber-reinforced composite laminates with near-zero coefficient of thermal expansion and extension-twisting coupling

Abstract

Composites exhibiting zero coefficient of thermal expansion (CTE) demonstrate substantial application prospects in engineering. This investigation develops a novel lamination paradigm for near-zero CTE laminates using carbon fiber-reinforced epoxy prepreg single-ply. A thermomechanical analytical model was developed to investigate the coupled deformation mechanisms and hygrothermal interactions. A design method for laminates based on geometric factors has been proposed, which can simultaneously achieve the hygro-thermal stability, near-zero CTE characteristics, and extension-twist coupling. Crucially, the designs of near-zero CTE asymmetric free-layup laminates and standard-layup laminates have been implemented. For near-zero CTE asymmetric free-layup laminates, a distinct inverse linear correlation was identified between the minimum required ply number and carbon fiber volume fraction; and maximum extension-twisting coupling demonstrate weak dependence on fiber volume fraction but strong negative correlation with ply numbers, showing gradual decline with increased layer numbers under constant fiber volume fractions. However, for standard-layup laminates, only when the number of layers is a multiple of 4, there exists a feasible solution for hygro-thermally stable near-zero CTE laminates with extension-twist coupling. And the coupling of the asymmetric free-layup laminate is significantly higher than that of the standard-layup laminate, with a maximum increase of more than 300 times. Robustness analysis confirms optimal stacking sequences’ effectiveness, and finite element simulations validate near-zero CTE properties, hygro-thermal stability, and extension-twisting coupling behavior. Intriguingly, the proposed methodology has extensible applicability for near-zero CTE thin plates and shells with arbitrary geometric configurations.