The Delamination and Fatigue Crack Propagation Behavior in A15052/AFRP Laminates Under Cyclic Bending Moment

반복-굽힘 모멘트의 진폭에 따른 A15052/AFRP 적층재의 층간분리 영역과 피로균열진전 거동

Song, Sam-Hong;Kim, Cheol-Ung

  • Published : 2001.08.01


Aluminum 5052/Aramid Fiber Reinforced Plastic(Al5052/AFRP) laminates are applied to the fuselage-wing intersection. The Al5052/AFRP laminates suffer from the cyclic bending moment of variable amplitude during the service. Therefore, the influence of cyclic bending moment on the delamination and the fatigue crack propagation behavior in Al5052/AFRP laminate was investigated in this study. Al5052/AFRP laminate composite consists of three thin sheets of Al5052 and two layers of unidirectional aramid fibers. The cyclic bending moment fatigue tests were performed with five different levels of bending moment. The shape and size of the delamination zone formed along the fatigue crack between Al5052 sheet and aramid fiber-adhesive layer were measured by an ultrasonic C-scan. The relationships between da/dN and ΔK, between the cyclic bending moment and the delamination zone size, and between the fiber bridging mechanism and the delamination zone were studied. Fiber failures were not observed in the delamination zone in this study. It represents that the fiber bridging modification factor should turn out to increase and that the fatigue crack growth rate should decrease. The shape of delamination zone turns out to be semi-elliptic with the contour decreased non-linearly toward the crack tip.


Cyclic Bending Moment;A15052/AFRP Laminate;Crack Bridging Effect;Delamination Zone;Fiber Bridging Modification Factor;Crack Growth Rate;C-Scan;Stress Intensity Factor Range


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