Grant-in-Aid for Scientific Research (A)
|Allocation Type||Single-year Grants|
Materials/Mechanics of materials
|Research Institution||Osaka University|
NAKANO Motohiro(1999) Graduate School of Engineering, Osaka University, Associate Professor, 大学院・工学研究科, 助教授 (40164256)
岸田 敬三 阪大, 工学(系)研究科, 教授 (00029068)
YAMAUCHI Yoshiaki Graduate School of Engineering, Osaka University, Research Associate, 大学院・工学研究科, 助手 (00252619)
TANAKA Kazuo Graduate School of Engineering, Osaka University, Associate Professor, 大学院・工学研究科, 助教授 (70171741)
中野 元博 大阪大学, 工学研究科, 助教授 (40164256)
|Project Period (FY)
1997 – 1999
Completed(Fiscal Year 1999)
|Budget Amount *help
¥33,200,000 (Direct Cost : ¥33,200,000)
Fiscal Year 1999 : ¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1998 : ¥2,600,000 (Direct Cost : ¥2,600,000)
Fiscal Year 1997 : ¥28,300,000 (Direct Cost : ¥28,300,000)
|Keywords||Laser / Shock wave / Orbital debris / CFRP / Spallation / Interlaminar delamination / High-speed flaming camera / Finite element analysis / 航空宇宙材料 / 層間はく離 / 破壊 / スポール / 超高速カメラ / 状態方程式 / 超高速ガメラ|
We examined hyper-velocity impact tests of CFRP (carbon fiber reinforced plastics) laminates using laser-accelerated Al flyers. Al flyers were accelerated to 6〜9km/s by irradiation of a short-pulsed intense laser beam. We succeeded in observing the deformation and fracture processes of the CFRP targets with a high-speed framing camera. It was found that the CFRP was splashed out from the collision surface of the targets. The deformation velocity of the back surface of the targets was about 100〜700m/s.
After the impact experiments, we investigated damages of the CFRP target with a optical microscope, a scanning electron microscope (SEM) and a laser microscope. We found fracture surfaces of mode I type exactly on the back of the flyer impact. Damages of mode II type were observed in the back where it came off the impact point a little. Multi-interlaminar delaminations were discovered by observation of the section of the targets.
The following fracture model of CFRP laminates under hyper-velocity impact loading is proposed as these results.
1. A crack is initiated by spallation (Mode I)
2. Then, the crack is propagated along carbon fibers by shear force (Mode II)
3. Finally, fibers at the back surface were broken by tension
Three-dimensional simulations of the hyper-velocity impact were performed using the Dyna3D. We introduced the fracture mechanisms presumed from the framing images at the experiments and the damage observation of the CFRP targets. Impact deformations with spallation agreed with the experiment results qualitatively.
Research Output (6results)