Composite Materials

· Three modes of crack formation due to transverse loading are illustrated.
· In (a) the bonding between the fiber and the matrix fails and the crack results from the stress induced delamination.
· If the matrix is weaker in tension than the matrix-fiber bond, the stress concentration near the fiber may initiate a matrix crack (b).
· The fiber may also fail under transverse loading, and (c) shows such a crack propagating into the matrix from the fiber.

From: Hull, "Introduction to Composite Materials," Cambridge (1992)