Transition between Cohesive and Interfacial Failure in a Laminate
Abstract
A theoretical condition has been derived for deflexion of a Griffith crack meeting a plane perpendicular interface in a thick plate of uniform elastic properties. The theory suggests that a short crack should be diverted along the interface when Rad<Rco/4π (1-ν 2),, where Rad is the adhesive energy of the interface Rco the cohesive energy of the bulk material and ν the Poisson ratio. This deflexion criterion has been checked by direct observation of a crack travelling through brittle transparent rubber to meet an adhesive interface with identical material. By varying the adhesive fracture energy during the rubber crosslinking process the crack was made to branch off and the theoretical criterion verified. Crack speed was shown to have a profound influence on the deflexion phenomenon. The effects of depth and modulus changes along the crack path were also investigated.
- Publication:
-
Proceedings of the Royal Society of London Series A
- Pub Date:
- June 1975
- DOI:
- 10.1098/rspa.1975.0102
- Bibcode:
- 1975RSPSA.344..287K