Impact damages induced by a low-velocity impact load on carbon fiber reinforced polymer (CFRP) composite plates fabricated with various stacking sequences were studied experimentally. The impact responses of the CFRP composite plates were significantly affected by the laminate stacking sequences. Three types of specimens, specifically quasi-isotropic, unidirectional, and cross-ply, were tested by a constant impact carrying the same impact energy level. An impact load of 3.44 kg, corresponding to 23.62 J, was applied to the center of each plate supported at the boundaries. The unidirectional composite plate showed the worst impact resistance and broke completely into two parts; this was followed by the quasi-isotropic lay-up plate that was perforated by the impact. The cross-ply composite plate exhibited the best resistance to the low-velocity impact load; in this case, the impactor bounced back. Impact parameters such as the peak impact force and absorbed energy were evaluated and compared for the impact resistant characterization of the composites made by different stacking sequences.

Abstract
 1. Introduction
 2. Experimentation
  2.1. Materials and specimens
  2.2. Experimental setup
 3. Results and Discussion
  3.1. Analysis of impact damage
  3.2. Force-time data
  3.3. Absorbed energy
 4. Conclusions
 References

• Furqan Ahmad(Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-338, Korea)
• Jung-Wuk Hong(Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-338, Korea)
• Heung Soap Choi(Department of Mechanical and Design Engineering, Hongik University, Sejong 339-701, Korea)
• Soo-Jin Park(Department of Chemistry, Inha University, Incheon 402-751, Korea)
• Myung Kyun Park(Department of Mechanical Engineering, Myongji University, Yongin 449-728, Korea) Corresponding author