143 雨滴によるGFRP衝撃の損傷機構に関する研究(OS5-2 異物衝突損傷)(OS5 材料の衝撃強度・損傷に関する最近の知見)  [in Japanese] 143 Damage Mechanism of GFRP Subject to Raindrop Imapct  [in Japanese]

When being subjected to high speed-low density particle impact such as a raindrop impact against the FRP aircraft in flight, FRP may be damaged. To evaluate the integrity of the structures, the damage mechanism caused by such impact must be clarified. GFRP disks of 100 mm in diameter were exposed to repeated impact of nylon balls in the experiments. Observation of the disk specimens during and after the experiments revealed that a white zone caused by nylon ball collision spread through the disk thickness. Sectioning of the disk specimen enables to observe the de-lamination between the second and the third layer. The close observation of the white zone indicated that the damage inside the zone consists of micro-cracking, and de-bonding of the fibers and the matrix To understand mechanisms of the observed damage modes, dynamic stress analysis was carried out by ANSYS FEM code. The analytical results indicated that shear stress component plays a dominant role to cause the white zone damage.