Compression after multiple low velocity impacts of NCF, 2D and 3D woven composites

This paper investigates the effect of the fabric architecture and the z-binding yarns on the compression after multiple impacts behavior of composites. Four fiber architectures are investigated: non-crimp fabric (NCF), 2D plain weave (2D-PW), 3D orthogonal plain (ORT-PW) and twill (ORT-TW) weave. The specimens were subjected to single and multiple low-velocity impacts at different locations with the same energy level (15 J). Non-destructive techniques including ultrasonic C-scanning, X-ray CT and Digital Image Correlation (DIC) are employed to quantitatively analyze and capture the Barely Visible Impact Damage (BVID) induced in the specimens. Although the absorbed energy was approximately the same, damage was the least in 3D woven architectures. In the case of compression after impact, 3D woven composites demonstrated a progressive damage behavior with the highest residual strength (~92%) while 2D plain weave and NCF specimens showed suddenly catastrophic damage and the residual strength of ~65% and ~55% respectively.