Effects of Stacking Sequence on the Application of the Single Specimen Technique to CLS Specimen

단일시편방법의 CLS 시편 적용시 적층성이 미치는 영향

Lee, Gyeong-Yeop;Yang, Jun-Ho

  • Published : 1999.11.01


The work factor approach, so-called single specimen technique could be used to determine energy release rate from a single test record for unidirectional CLS specimen. In the present study, the work factor approach was extended to determine the mixed-mode fracture toughness of multi-directional graphite/epoxy laminated composites. Multi-directional CLS specimens were used for fracture tests. The stacking sequences used for the lap and the strap were $[90_2/0_2]_s/[0_4/90_4]_s$ and $[0/\pm45/0]_s/[0_2/\pm45_2/0_2]_2$, respectively. For both cases, the fracture toughness determined from the work factor approach was compared with that determined from the compliance method. It was found that both methods produced fracture toughness within a maximum 15% difference for each stacking sequence. The fractography analysis also showed that the fiber bridging occurred for$[0/\pm45/0]_s/[0_2/\pm45_2/0_2]_2$ case while it did not occur for $[90_2/0_2]_s/[0_4/90_4]_s$ case.


Fiber-reinforced Composites;CLS Specimen;Energy Release Rate;Mixed-Mode Fracture Toughness;Compliance;Elastic Work Factor;Fiber Bridging


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