Experimental investigation on the quasi-static penetration behavior of curved multi-axial warp-knitted composites

The quasi-static penetration tests of the curved glass/phenolic multi-axial warp-knitted (MWK) composites with two types of preform structures and in three different curvatures were implemented. Three phases — elastic deformation phase, progressive damage phase and tension-shear phase were identified to present the different damage behavior stages of curved glass/phenolic MWK composites under quasi-static penetration. Several types of damage modes including matrix cracking, tension-shear of the materials, fiber fracture and interlayer delamination were revealed based on the load-displacement curves and morphology analyses. The results showed that the reinforcement structure and the curvature of the specimens did provide obvious influence onto the quasi-static penetration behaviors of curved glass/phenolic MWK composites and they could be utilized in pointed purposes according to the different mechanical features.