저속충격에 의한 복합재료 적층판의 손상

다국어 초록 (Multilingual Abstract)

The study investigated the nondestructive characteristics of damage, caused by low-velocity impact, on symmetric cross-ply laminates, composed of [0o/90o]16s, 24s, 32s, 48s. The thickness of the laminates was 2, 3, 4 and 6 ㎜, respectively. The impact machine used, Model 8250 Dynatup Instron, was a drop-weight type that employed gravity. The impact velocities used in this experiment were 0.75, 0.90, 1.05, 1.20 and 1.35 m/sec, respectively. Both the load and the deformation increased when the impact velocity was increased. Further, when the load increased with the laminate thickness in the same impact velocity, the deformation still decreased. The extensional velocity was quick, as the laminate thickness increased in the same impact velocity and the impact velocity increased in the same laminate thickness. In the ultrasonic scans, the damaged area represented a dimmed zone. This is due to the fact that the wave, after the partial reflection by the deflects, does not have enough energy to touch the opposite side or to come back from it. The damaged laminate areas differed, according to the laminate thickness and the impact velocity. The extensional velocities are lower in the 0o direction and higher in the 900 direction, when the size of the defect increases. However, it was difficult to draw any conclusion for the extensional velocities in the 45o direction.

목차 (Table of Contents)

• ABSTRACT
• 1. 서론
• 2. 시험편 및 실험방법
• 3. 실험결과 및 고찰
• 4. 결론
• 참고문헌

참고문헌 (Reference)

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2 "시간-주파수 해석법에 의한 CFRP의 파괴 거동" 21 (21): 39-45, 2001

3 "Wave Propagation in a Plate with Defects" 17 : 121-128, 1998

4 "The Impact Resistance of Composite Materials - A Review" 22 (22): 347-362, 1991

5 "Modeling of Impacts on Composite Structures" 51 : 129-138, 2001

6 "Impact on Laminated Composite" 47 : 517-544, 1994

7 "Impact Response and Elastodynamics of Composite Materials" 116. : 1990

8 "CFRP적층 형태에 따른 파괴시 음향방출 신호특성" 16 (16): 67-71, 2002

9 "Advanced AE Techniques in Composite Materials Research J. of Acoustic Emission" 14 : 1-11, 1996