Composite Materials

· When the load applied to a composite increases, the system can enter the plastic deformation range and finally fracture.
· A generic constant strain-rate stress/ strain curve for a composite is shown. Stage I is the elastic range, stage II shows matrix plastic deformation, in stage III both the matrix & fiber are plastic, finally fiber fracture occurs, the matrix continues to deform, and the composite fractures when the matrix fractures.

From: Courtney,
"Mechanical Behavior of Materials,"
McGraw Hill (1990)