High-Velocity Impact Damage in CFRP Unidirectional and Cross-Ply Laminates
Keiji OGI, Takaaki TANAKA, Shigeki YASHIRO and Akinori YOSHIMURA
Abstract:This paper aims at characterizing the high-velocity impact damage behavior in carbon fiber reinforced plastic (CFRP) unidirectional (UD) and cross-ply (CP) laminates. First, the surface and internal damages of CFRP plates impacted at a velocity of 200 and 430 m/s were observed by using optical microscopy together with radiography. Next, dynamic finite element analysis was performed to simulate the damage process. Cohesive elements were introduced to express the delamination and splitting cracks while the maximum stress fracture criteria were employed to express the intralaminar failure. Finally, the simulations were compared with the experiment results to verify the reasonability of the analysis. The damage process in both laminates was as follows: 1. A crater accompanied by splitting cracks is generated at the impact point on the front surface while splitting cracks due to bending are observed on the back surface. 2. Cone-shaped matrix cracking is observed in the UD laminate while few matrix cracking is generated in the CP laminate. 3. The shape of the delamination in the UD and CP laminates is a galaxy and a circle, respectively. Delamination size is larger in the CP laminate than in the UD laminate, which results in higher energy absorption capability in the CP laminate. Simulations are in qualitatively good agreement with the experiment results. Key Words:CFRP, High-velocity impact, Delamination, Matrix cracking, FEM, Cohesive element