If the energy release rate G during delamination growth exceeds the critical value G_IC or G_IIC, what is the predicted outcome?

If the energy release rate G during delamination growth exceeds the critical value G_IC or G_IIC, what is the predicted outcome?

• A. The laminate will automatically recover and heal the delamination.
• B. Delamination will propagate and grow.
• C. The laminate becomes more resistant to fracture.
• D. The material will instantly melt.

Answer: (B)

The energy release rate G represents the driving force for creating new surface as a crack grows. When G exceeds the material’s fracture resistance for delamination—G_IC for Mode I opening or G_IIC for Mode II in-plane shear—the energy available to drive crack growth is greater than what the material can resist. This causes the delamination to propagate and enlarge. The other options don’t fit this physical picture: healing is not driven by exceeding G, increasing resistance doesn’t occur when G is high, and melting isn’t relevant to this fracture-mechanics criterion.

The energy release rate G represents the driving force for creating new surface as a crack grows. When G exceeds the material’s fracture resistance for delamination—G_IC for Mode I opening or G_IIC for Mode II in-plane shear—the energy available to drive crack growth is greater than what the material can resist. This causes the delamination to propagate and enlarge. The other options don’t fit this physical picture: healing is not driven by exceeding G, increasing resistance doesn’t occur when G is high, and melting isn’t relevant to this fracture-mechanics criterion.