Abstract: Needled carbon felt reinforced resin-based carbon composites was prepared by liquid impregnation-carbonization process (LPI) using non-woven cloth/web needle carbon fiber felt with different needle-punching densities as preform, and phenolic resin as precursor. Three-point bending and compression tests were employed to study the influence of needle density on the mechanical properties of resin-based carbon composites. The damage and failure mechanisms of needled carbon felt reinforced resin-based carbon composites were also discussed. The results show that the needle-punching density has a great influence on the pore size distribution of preform, it affects the impregnation-carbonization process, which consequently result in the mechanical properties of the resin-based carbon composites when the density of needled carbon felt is 0.4 g/cm3. In the meantime, when the needle depth is 13 mm, with the needle density increasing from 20 to 50 punch/cm2, the flexural properties of composites increase firstly and then decrease. When the needle density is 40 punch/cm2, the flexural properties of composites reach the highest. The main failure mode of bending is cracking failure of the bottom inverted “V” type. In addition, with the increase of the needle density, the transverse compression performance of the composite is basically unchanged, and the longitudinal compression performance is gradually improved. There are three failure modes of transverse compression such as stratification and interlayer failure, interlayer shear failure and resin-based carbon crushing failure. With the increase of needle density, the failure mode of longitudinal compression of composites is changed from interlayer delamination and shear failure to fracture failure of multilayer fibers.
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