Composite Materials

· The diagrams below illustrate the failure features of a uniaxial composite loaded in tension and with V_f > V_f^'
· In (a) the material is in the elastic range, for (b) ε^*_f > ε^*_m and the matrix has fractured but the fibers able to take the load transfer, (c) shows the same situation with multiple matrix cracking , in (d) the fibers fracture first since ε^*_m > ε^*_f . The matrix is stable after load transfer.

· The multiple resin cracks in (c) result from the continued strong coupling between the fiber and the matrix after an initial matrix failure. The increasing strain in the fibers causes additional strain in the matrix which then develops additional cracks.

From: Hull, "Introduction to Composite Materials."