Preparation and characterization of high load‐bearing needled composite preform based on novel ordered short fiber network needling method

Abstract Needled preform and its composite using felt and base cloth stacked needled have small fiber volume fraction and relatively weak mechanical properties, which are difficult to meet the service requirements of structural and functional integrated components of high‐speed aircraft. Responding to this issue, this paper proposed a new method for preparing high load‐bearing needled composite preform based on ordered short fiber network needling. The high load‐bearing needled preforms were prepared by designing different structural parameters of ordered short fiber network and forming process parameters, and then preform structure was characterized and mechanical properties were tested. The results showed that using ordered short fiber network as carrier of the short fibers, the formed needled fiber bundles were longer and denser, volume content of needled fiber bundles and mechanical properties of needled preform were greatly improved, and needled fiber bundles volume content of ordered short fiber network reinforced needled preform was 1.5 times and 46.3 times that of half‐cut cloth and felt respectively. Compared with traditional felt needled preform and half‐cut cloth needled preform, the interlaminar peeling strength of the ordered short fiber network reinforced needled preform increased by up to 246.4% and 49.2%, respectively. The tensile strength of ordered short fiber network reinforced needled preform was 12.9% higher than that of half‐cut cloth in X ‐axis direction. In addition, the effects of ordered short fiber network structure, short fiber length, areal density and needling density on the needled preform structure and properties were also revealed. Highlights High load‐bearing needled composite preform was prepared based on novel ordered short fiber network needling method. The needled fiber bundles formed by using ordered short fiber network were longer and denser, and their volume content was 46.3 times that of felt needled preform. The interlaminar peeling strength of the ordered short fiber network reinforced needled preform increased by up to 246.4%. The tensile strength of ordered short fiber network reinforced needled preform was 12.9% greater than half‐cut cloth in the X ‐axis direction.