Understanding friction and wear properties of carbon fiber/epoxy stitched composites

Due to its low friction coefficient and wear rate, and good self-lubrication, carbon fiber reinforced polymer (CFRP) composite is used as friction material. The easy interlaminar delamination and low impact damage tolerance of conventional CFRP laminates lead the friction materials to wear seriously, which causes the early-stage failure. Here, carbon fiber/epoxy stitched composites were prepared by the resin transfer molding technology. Effects of load and stitch parameters on the friction and wear properties of stitched composites under dry conditions were investigated through experiment and simulation. The coefficients of friction (COFs) of composites increase linearly at the initial stage, and then decrease from a maximum peak to a relatively stable state value. Samples with a high stitch density and a small stitch spacing along the sliding direction has low COF values and wear rates. With the increase of the normal load, COFs and the wear rate both decrease first and then increase. The wear tracks on the surface of CF/EP stitched composites are generated by comprehensive effects of cutting, adhesive and fatigue wears. This study provides comprehensive characterization and deep understanding of friction and wear properties of carbon fiber/epoxy stitched composites, which will broaden the CFRP application as frication material.