Two- and three-dimensional finite-element analyses have been carried out to investigate interlaminar crack growth in composite double-cantilever beam (DCB) specimens. The results revealed that crack-tip bluntness causes multiple stress concentrations along the crack contour. By increasing the bluntness, the highest stress point moves from the tip towards the corner along the crack contour. This increases possibility of crack growth towards the fibre/matrix interface. The results also show relatively high tensile stress along the interface near the insert film, suggesting that for DCB specimens with a weak fibre/ matrix interface, a crack is likely to start at the interface, not from the insert film. Experimental evidence supporting the analytical results was obtained by scanning electron microscopy of the fracture of glass-fibre composites. The study concludes that crack-tip bluntness has an important role in initial crack growth in DCB specimens, and should be considered for design of interlaminar fracture testing of composites.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites