The Evaluation of Interlaminar Fracture Toughness and AE Characteristics in a Plain Woven CFRP Composite with ENF Specimen

ENF 시험편을 이용한 평직 CFRP의 층간파괴인성 및 AE 특성 평가

Woven fabrics composites are used as primary structural components in many applications because of their superior properties that offer high specific strength and stiffness. However, the complexity of the fabric structure makes understanding of their failure behavior very difficult. Also, laminate woven fabrics CFRP have unique failure mechanisms such as fiber bridging, fiber/matrix crack and so on. In particular, the delamination phenomenon of the composite materials is one of the most frequent failure mechanisms. So, we estimated interlaminar fracture and damage in composites using as ENF specimen by a 3 point bending test. And AE characteristics were examined for crack propagation on plain woven CFRP. We obtained the following conclusions from the results of the evaluation of the 3 point bending fracture test and AE characteristic estimation. AE counts of maximum crack length were obtained as $85.97{\times}10^4\;and\;93{\times}10^3\;for\;a_0/L=0.3$ and 0.6, respectively. Also the maximum amplitudes were over 80dB at both $a_0/L=0.3\;and\;0.6$. $G_{IIc}$ at that's $a_0/L$ ratio were obtained with $1.07kJ/m^2\;and\;3.79kJ/m^2$.