Elastic properties and multi-scale design of long carbon fiber nonwoven reinforced plane-based isotropic composite

Abstract

Carbon fiber reinforced composite is considered as a potential substitutes used in the lightweight of automotive engineering. Nevertheless, the high price and complicated manufacturing process remain challenges for the large-scale application of conventional carbon fibers. In this study, a novel plane isotropic composite reinforced by long carbon fiber non-woven is introduced, which overcomes the obstacles in the application of carbon fiber at present. A multi-scale optimization method is proposed to realize the performance optimization and lightweight design of composite components. The linear elastic properties of long carbon fiber non-woven composite (LCFNC) were studied experimentally and analytically. The predictions of homogenization theory were found to be very similar to the experimental results within an interval of volume fraction. Then the relationship between microstructure and material performance was evaluated in detail. The results showed that there is a critical point for the influence of aspect ratio to the material properties. Thirdly, thickness of LCFNC at macro scales and the fiber parameters at micro scales were simultaneously optimized by Non-dominated sorting genetic algorithm-II (NSGA- II) to enforce multi-objective optimization design. Finally, the lightweight design of automobile hood was performed by the LCFNC and the proposed method. The results showed that the weight of automobile hood was reduced by 37%, while exhibiting better stiffness and strength performance compared with the conventional steel.